SuperCat Stove

There are many reasons why you might want a lightweight stove that's powerful enough to boil water.  I carry one on backpacking trips, but one would also be handy if the power goes out at your home (hurricane or other natural disaster).

Andrew Skurka has a page showing you how to make the awesomely simple and very efficient SuperCat stove, so called because you make it from a cat food can.  Seriously.  I can vouch for this design because it's the exact same stove I use when camping.

Check it out.

Building A Model Rocket - part 6

We're ready to play with paint!

If you want to, you can spend a little time with some extra-fine sandpaper to smooth the glue fillets we applied along the fins. Like anything other paint job, prep is 90% of the way to getting a great finish.

First step is the primer. Use Krylon or Rustoleum, grey, white, or ruddy brown, whatever you can find as long as it's sandable.

You'll need to make a simple tool to hold the rocket while spraying paint. The easiest way is to roll up a sheet of newspaper into a tight cone, and then slip it into the motor mount. You can use a couple strips of masking tape to hold it together. Then you hold the 'wand' with one hand while spraying paint with the other.

The key to getting a nice finish using spray paint is to use light coats. By light, I mean you should still be able to see through the paint until after your third coat.

The primer dries quickly, so this doesn't take a long time. You want to spray many light coats instead of one or two heavy ones. Once you've got complete coverage (up to 4 or 5 coats), let it dry - read the can, it's usually less than an hour - and then lightly sand the entire rocket with that extra-fine sandpaper. Let the rocket sit and dry for at least 24 hours.

It's possible to get near-professional results with this method, but you're going to put in plenty of sandpaper time and effort. If you wanted to, you can repeat the entire priming/sanding process two or more times, running a tack cloth over the surface in between each sanding session.

Next comes the color coat. Once again, I tend to stay with Krylon or Rustoleum. Since the Fat Boy has white decals, I'm going to use a dark color so they show up well. If I were going to paint the rocket a lighter color and I'd used a dark gray or brown primer, I'd then spray a couple of light coats of white first, just to lighten up the final finish coats.

The same spray techniques apply with the color coat. Spray multiple light coats to prevent runs and drips. Read the can carefully and follow their directions for drying times. Sometimes you have to wait a minimum of time between coats, or put the next coat on within a certain time frame.

I suppose I should mention that you should always paint outside. Even if it's cold out, you can go out, spray the coat of paint, and then bring the rocket inside until it's time for the next coat of paint.

Once you get the rocket completely painted with the color coat, let it dry. Because of the many coats used (or if you got impatiant, the thick cover coat), the rocket needs to sit for at least 24-48 hours, and longer is better.

Now, specifically for this rocket, here's what I did: I used Rustoleum sandable primer, and Krylon gloss white, gloss banner red and gloss regal blue, all in spray cans.

Step one was applying four light coats of primer, sanding with 320 grit sandpaper between coats. Then I let it sit for several days.

Next up, an all-over coat of blue, applied in 4-5 light coats, followed by one fairly heavy 'finish' coat. I let the rocket sit in the sun for about ten minutes between coats. The nice thing about Krylon is you can recoat anytime.

If I were going to be masking this rocket off to paint different colors, then I would have let it sit for several days for the blue paint to fully dry. Instead, I decided to 'fade' the colors together. Starting at the top, I sprayed several coats of white over the blue, making sure I never went as far down as the joint where the nose cone meets the body tube. I concentrated more paint towards the top of the rocket to completely cover the tip of the nose. The nice thing about this 'fade' technique is that you can just do it by eye and stop when it looks good to you.

I also did a light fade of white in a band near the top of the fins so that the red and blue would contrast better and to brighten up the red a little. Once that had dried a few minutes, I sprayed the red in the same manner as the white. Concentrate the color more towards the ends of the fins and bottom of the rocket to create the 'fade' into blue. I was careful to not completely cover the white band.

The best tool for painting a rocket like this is a 5/8" dowel about 18" long (or you can use a rolled-up newspaper like described above). Slide it up into the motor mount and you have a wand to hold and manipulate the positioning of the rocket while you spray.

Several hours later (I got impatient, you should wait a day or two), I cut out the decal and put it on the side of the rocket. I didn't use the fin decals. I normally don't like the newer self-adhesive kind, but this worked ok.

I also thought about cutting out the "FAT BOY" letters to write something like "OY BATF", but it's been done before, so I stuck with the original.

So that's it! We now have a completed rocket. If you build and fly your own, I'd love to hear about your experiences and the maiden flight!

Building A Model Rocket - part 5

Parachutes.

Technically, what comes with your typical model rocket are parasheets, and real parachutes aren't measured in diameter, but in square inches (or feet) of canopy. Model rockets have been doing things their own way since the beginning, and it works just fine. The Fat Boy has a purple and white chute, which is 18" across. For reference, Estes 12" chutes are orange and white, and 24" chutes are red and white.

Lately, Estes has been including pre-assembled parachutes in its kits. If you have one, all you really need to do is make sure that the knots are tight. If you want to make the parachute better, follow along as I explain the steps to construct one of the Estes chutes, and re-do a couple of simple things.

Lay out the plastic sheet and, using an x-acto knife and metal straightedge, cut it out on the outside lines. It's a hexagonal shape, and the parachute shrouds will be tied into each corner.

At this point I always stick a binder reinforcement onto each corner. These little self-adhesive paper rings are available in the stationery section of most stores, and keep the strings from tearing through the plastic. Alternatively, you can use a small square of duct tape (about 1/4" square). Whatever you use (if you use anything) make sure it lays flat so the strings can't catch on it.

Stretch the string out and fold it back on itself twice. You're going to cut it into three equal lengths. While we're at it, we'll start calling them "shroud lines" too instead of the "strings".

Using a sharp pencil point or thick needle, punch a hole in each corner of the chute, inside the reinforcement ring or tape square. Thread an end of a shroud line through, then tie a double knot and pull it tight. Tie the other end of the shroud line to the corner immediately to either side. Do all three shroud lines in the same way, so that each corner has one line attached and you have three loops of line coming off of the chute.

While it's flat, decide whether you'd like to cut a spill hole. This is a hole in the apex of the canopy that lets the air out from underneath. The reason for it is that without it, a chute will tend to oscillate in the air as the air spills out from the edges of the canopy. If you remove enough, it's also a good way to increase the speed that the rocket comes down beacuse you're removing a part of the canopy. On real chutes, adding a spill hole can actually increase the efficiency of a canopy, which can decrease its descent rate (make it come down slower). Parachutes are subject to the same laws of aerodynamics as rockets, airplanes and birds.

Estes chutes have the optional spill hole already marked. Just use your xacto knife to cut out the dotted lines around the center logo. I do recommend doing this for the Fat Boy, because that 18" chute is awfully big for the weight of the rocket.

If you ever want to make your own model rocket parachute, it's easy to do. Any plastic bag material will work, or you can use the heavier plastic from those rolls of picnic tablecovers. Whatever you use, add some color if needed with permanent markers or hilighter marker because a clear plastic chute will be invisible at altitude.

For shroud lines, you can use heavy carpet thread, braided nylon, dacron or kevlar, or a brand of dental floss called Glide. The Glide is made of teflon and is fire resistant, which is a good thing for our purposes.

To attach the parachute, gather all of the shroud lines and thread them through the plastic loop on the nosecone. Pull the lines through and open them enough to slip the canopy through. Keep tightening the lines by lightly pulling on the canopy until the shroud lines snug up against the nosecone loop.

Alternately, you can attach the chute to a fishing swivel using the same steps. This way, you can move the chute from one rocket to another just by opening the swivel and reattaching it to another nosecone loop. You might need to use needlenose pliers for this. There's a picture of fishing swivels in part 2 of this series. The shroud lines go through the small loop at one end, and the big end opens like a safety pin so you can attach it to the nose cone.

Now a little bit about aerodynamics and what makes these rockets safe to fly. For the Fat Boy kit, it should be perfectly stable as built, assuming you didn't add a bunch of weight at the aft end. Not all kits are naturally stable, so if it comes with a chunk of clay in the kit, you'll need to put it inside the nosecone as the kit instructions direct. In any event, you should at least do a quick check on a completed kit. The following tells how and why.

On standard rockets - fins at one end, nose cone at the other, nothing really odd going on in between - there are two places on the rocket that are critical to stability. First is the Center of Gravity (CG) and it's the point where the rocket weighs the same in either direction, like a fulcrum of a teeter-totter, or perfectly balanced scales. In the exact same way as a teeter-totter, you determine the CG by balancing the rocket on a pencil or some such (I use my finger - it's close enough). The point where it balances is the CG. Put a little pencil mark there.

I talked a little bit about the CG here without naming it (the bit about the hand out the window). The CG is the point that the rocket will rotate around as the fins correct the flight path.

The second place is called the Center of Pressure (CP). This one is a little harder to explain, but just like the Center of Gravity is where all the weight of a rocket balances, the CP is where all the various aerodynamic forces balance. These forces include thrust, drag and gravity, as well as the roll, pitch and yaw of the flying rocket.

To determine the CP, the easiest way is to make a cardboard cutout of the rocket outline, then balance it on something like you did for the CG. The difference here being that the cardboard is only two dimensional. It also represents the rocket flying through the air sideways (90 degree angle of attack), since it's presenting the largest possible cross-section to view. What this does is give the most conservative CP of the airframe. This CP will be farther forward - toward the nose - than any other angle of attack.

Your rocket will be stable if the Center of Gravity (CG) is in front of the Center of Pressure (CP) by at least one diameter of the main body (caliber). So if the CG is twice as far in front of the CP as the body diameter, then the rocket has two calibers of stability.

All this is great for regular rockets, but the Fat Boy is rather short and squatty, so the margin for stability is shortened a bit, and you'll find you probably have around 3/4 of a caliber stability, which is fine for that kit.

To move the CG forward, you can add weight to the front of the rocket, or add length. To move the CP backwards, you can either add length to the rocket, or increase the size of the fins, or the number of fins, or sweep them backwards.

Having the CG too far ahead of the CP is called 'overstable', and can cause the rocket to be overly sensitive to wind gusts. It can behave like a weathervane and cock sharply into a breeze, just like a... uh, weathervane.

One last thing, you should measure the CG when the rocket is prepared to fly - motor, chute and the works, because that's how the rocket will actually fly. Sounds dumb, but it's not. The motor can shift the CG significantly backwards.

A simple test for stability is called the 'swing test'. Find the rocket's CG (remember, ready to fly configuration), and tie a long piece of string around it at that point - use a spot of tape to hold it in place. Then take the string and swing the rocket around your head like you were using a rope lasso. The rocket should settle into place and look like it's flying horizontally around you. Sometimes it will settle in tail first, that's ok. And for certain weird cases, a rocket will tumble as unstable, even though in actual flight it'll be fine. But for 99% of the time, this is a good test, and even scale models of real rockets have been checked this way by engineers in informal testing.

Or you can trust the kit. :) Knowing where the CP and CG are become critical when you design and build your own rockets.

The math to determine the CP isn't that difficult, and was worked out in general form by Jim Barrowman in 1966. Known as the 'Barrowman Equations' (duh - and the link is a .pdf document), they simplify the process by making several assumptions about the rocket and aerodynamic environment. They're still a useful approximation and are still frequently used.

So what kinds of practical use is all this CG and CP hocus-pocus?

Well, for our rockets, we want them to be stable so that they fly straight and safe, especially since model rockets are unguided, and rely on fins to keep it going straight up.

In general, an airplane (real or model), wants the CG and CP to be closer together, so that they're neutrally stable. That way, the plane is easy to steer because the airframe isn't fighting to keep itself pointing in the same direction. A military fighter is going to be closer to unstable, and thus more nimble, than a passenger jet.

Military missiles, especially air-to-air versions like the Sidewinder, are purposely designed to be unstable. They can turn-on-a-dime, figuratively speaking, and the only thing that allows them to fly straight at all is the onboard guidance computer, and controls like fins that rotate, tiny steering rockets along the sides, or thrust deflection. Larger missiles without fins steer by changing the direction that the engine bell is pointing, using the rocket thrust itself to steer.

Next up: Paint!

Building A Model Rocket - part 4

Cardboard tubes, balsa, paper and plywood all fall into the category of wood products, and the best adhesive for these materials is wood glue. A well-fit joint will be stronger with wood glue than even epoxy or industrial grade cyano-acrylate (CA) - aka 'superglue'. The technique to make these indestructable glue joins is called the 'double-glue method'.

That 'indestructable' claim isn't exageration either, because the materials being joined will break before the glue bond fails. It's not unheard of to have a fin break just beyond the glue.

So what's this secret way to glue rockets together? It's simple.

1. Lay a light bead of glue along the root of the fin.
2. Put the fin into place so the glue gets onto both parts to be joined. In this case, the fin root and the body tube.
3. Pull the pieces apart. There should be a light coat of glue on both pieces. Let it dry almost completely.
4. Put another bead of glue on the fin root, then press the two pieces together for good.

The reason this works is because the first coat of glue penetrates the materials to be joined, and the second coat chemically bonds with the first, locking eveything together. This makes for an incredibly strong joint.

For the Fat Boy, I suggest just sliding the motor mount assembly into position without glue (the metal motor hook will be sticking out the bottom), then gluing the fins into position. Use plenty of glue on the fin tabs which go into the slots of the body, and less on the parts of the fin root that don't fit into the slots.

It's fairly important to get the fins straight, but vertical alignment is more important that being perfectly spaced or perpendicular to the body tube. Since the Fat Boy has slots that the fins fit into, this is taken care of for you. When gluing the fins into place, take the nose cone off and set the rocket body upside down on your work surface so that you can look down at it and better gauge alignment. Looking from above, all three fins should point to an imaginary spot directly in the middle of the motor mount tube. Wipe excess glue away with your finger, smoothing it into the joint where the fin meets the body tube.



Tip: If you've already bought motors, put one in the motor mount because it's easier to 'aim' the fins at the small nozzle than it is at the imaginary point in the empty tube.

Leave that be and let's assemble the shock cord mount. Hopefully you've taken my suggestion and picked up a package of 1/8" sewing elastic, because the length supplied with the kit is just too short.

In the instructions is a diagram for the standard Estes shock cord mount, sometimes called a 'paper sandwich'. If you're building a different kit then follow whatever directions you've got, or use the following diagram to make one like ours (click it and it gets bigger). At the end, you should have a truncated pyramid shape folded twice with one end of the elastic embedded inside. Here, you should be generous with the glue, yet squeeze it out so that it's as flat as possible.



Let everything dry. Be patient, give it a couple of hours.

For each side of each fin, run a small bead of glue along the edge where the fin meets the body tube. Then take your finger and smooth the glue into the crease. Don't wipe too much glue away, just try to leave a smooth rounded fillet. If you're using brown carpenters glue, the gel formula will keep the glue from running and you can do all the fin fillets at one time. Otherwise, just do one or two at a time and let it dry before moving on to the next. These glue fillets add lots of strength to the fin joint and you should always do them.

We didn't glue in the motor mount before attaching the fins, so lets do that now as well. Apply the glue fillet to the seam where the centering rings meet the body tube, just like you did with the fins. Smooth it with your finger, and since we're using wood glue I recommend putting a second coat on after the first is dry. Do this for both ends of the motor mount. The top fillet is deep inside the body tube, so what you can do is take a long scrap of the balsa that the fins came from, and use that to apply the glue. Don't worry about being perfectly neat, the important thing is getting the joint glued.



The instructions tell you to mark a line between the fins to help you align the launch lug. Instead of that, I usually install the lug in the corner where the fin meets the body tube. This way the lug is automatically lined up vertically (the pre-cut fin slots help), plus it's stronger for the extra surface to glue against.

Finally, it's time to glue the shock cord mount into place. You should have a "paper sandwich" which has the elastic coming out of one end. Use a good bit of glue, and attach the mount to the inside of the top of the body tube, with the elastic pointing up towards the nose cone. Make sure you get it far enough down inside the body so that it doesn't interfere with the shoulder of the nose cone.



You can trim the elastic to a length of about 24" or so before or after gluing the mount into place.

The reason for making the shock cord longer is a phenomenon known as the 'estes dent'. What happens is that during the flight, the nose cone is propelled forward by the ejection charge. If the shock cord is too short, then the nose cone stretches the elastic until it zings right back at the rocket, crunching the top of the body tube. Using a longer shock cord prevents this from happening. A good rule of thumb is to make the shock cord 2-3 times the length of the body tube.

Once the shock cord mount is dry, use more glue to make sure it's firmly glued into place. This part is going to keep your rocket attached to the parachute and nose cone, so use some care here. You also want to make sure it's as flat as possible, so that there's nothing to snag the parachute on it's way out.

When everything is dry, tie the end of the elastic shock cord to the plastic loop of the nose cone. Use a double knot and make sure it's tight.

At this point, the rocket is ready to fly except for the parachute. Next Friday we'll put up the next part talking about the parachute and discuss flight stability a little more. We'll also get ready to paint the rocket.

Building A Model Rocket - part 3

It's time to spread some glue! I know, finally, right?

This is a series of posts where we're building a basic model rocket online. Each post shows part of the process step by step, including pictures and passing along tips and tricks I've learned along the way. To learn more about what model rocketry is about, see this Q&A.

Follow along and when we're done you'll have built and flown your first model rocket. Questions asked from previous posts are answered too, so if you have questions, please leave them in the comments or email me.

This time we're going to put together the motor mount. It's a simple process. If you're building the Fat Boy, then the motor mount consists of the motor tube, two cardboard centering rings, a metal engine hook, and the black engine holder ring. Every model rocket has this setup, with minor variations. I'll talk about that after assembly.

Test fit the centering rings on the motor tube first. I had to widen the inner holes a little bit by reaming it out with a pair of scissors. The rings should slide on easily, don't force it.

Mark the motor tube (it's not quite 3" long) according to the instructions. Carefully push the tip of your x-acto knife into the tube at the proper mark to make a small slit. The slit only has to be wide enough to accept the width of the motor hook.

Push the "L" shaped end of the motor hook into that slit, so that the motor hook lays flat along the length of the tube. Then slide the black engine holder ring onto the tube and over the motor hook. Don't glue anything yet.

Now slide the rings onto the tube. If one ring has a notch in the inner cutout, then that notch fits over the squiggly end of the motor hook. The idea here is to allow you to lift the overhanging end of the motor hook out of the way to insert and remove the rocket motors.

I recommend putting a couple of wraps of masking tape around the motor tube and hook right where the hook goes into that slit you cut. It's not strictly necessary, but it's simple insurance to prevent a potential problem later.

Now it all looks like this. Nothing is glued yet, but we're ready to go.



Put a bead of glue all the way around the place where the motor tube goes through the centering ring. If you're using the gelled stuff that won't run, do both sides of both rings all at once, otherwise just set the motor mount on end and do the 'top' surfaces. When dry, flip it over and do the other sides.

You don't need a ton of glue here, but use enough to completely circle the tube. Use your finger to lightly smooth it into the corner of the joint and then straighten out the centering ring again if needed.

Set it aside to dry.

While's it's drying, I'll explain how this whole assembly works. The rocket motor goes into the motor tube and rests against the hook (the one through the slit). When the motor ignites it pushes against that hook, which is secured to the motor tube, which is glued to the centering rings, which will be glued to the airframe. Simply put, the motor takes off, and everything else goes along for the ride. That's the reason for the wraps of masking tape I recommended earlier - to keep the hook end in place. If the hook slips out of the slot, then the motor will just thrust straight up through the rocket and blast off by itself, knocking the nosecone out of the way on it's way through. Entertaining, but not in any way a successful flight.

Some kits use a 'thrust ring' to prevent this instead of, or in addition to the motor hook. It's just a cardboard ring that is glued inside the motor tube where the hook enters, to give the motor something substantial to push against.

The other end of the motor hook (the squiggly bit), has an important function as well. Besides letting you move the hook out of the way to extract an expended motor, it also keeps the motor in place when the ejection charge goes off, which deploys the parachute.

Isaac Newton's third law of motion states that for each action there is an equal and opposite reaction. The ejection charge of a model rocket motor fires forward (towards the nose, which means that the body of the motor is forced backwards. Without the motor hook in the way, the motor would eject out the back of the rocket and the nosecone would stay in place (meaning no chute). Lawn dart.

If your rocket doesn't have a motor hook, then you can do a couple of things. First off is what they call friction fit. This is simple and wonderfully effective. Use pieces of masking tape (I use enough for about a half-wrap) around the end of the motor case closest to the nozzle end, until the motor is a very snug fit in the motor mount. The idea is to make it easier for the nosecone to come off than it is to expel the motor, 'path of least resistance' style. Another method that I've used is to put the motor into place, and then use a couple wraps of masking tape around the motor and motor mount tube. You can also do both, but that's usually overkill.

Next up will be the shock cord mount, and putting the motor mount into the body tube. Maybe a little bit about the chute too.

Building A Model Rocket - part 2

This is a series of posts where we're building a basic model rocket online. Each post shows part of the process step by step, including pictures and passing along tips and tricks I've learned along the way. To learn more about what model rocketry is about, see this Q&A.

I hope you follow along because when we get done you'll have built and flown your first model rocket. Questions asked from previous posts are answered too, so if you have questions, please leave them in the comments or email me.

The instructions for most model rocket kits are wonderful. Estes has been doing this for years, and their experience shows. Let me stress one point right up front: always, Always, ALWAYS follow their suggestions for glues to use. You can sometimes use an alternate (I have almost 20 different kinds of adhesives for various situations), but their recommended glue will give you the strongest bond.

Looking at the Parts

Almost everything that needs assembly tells you to lay out the parts and make sure you have everything, and also to read through the directions first to understand things. This is a simple kit, so do it if you'd like, but it won't be a problem if you don't. For more complicated kits, I do recommend doing it.

Lets look at the various parts, most of which are obvious. The biggest tube with the slots cut in one end is the body tube. In a simple rocket like this, it's main purpose is to hold all of the important bits in their correct places. The nose cone is straightforward, as are the fins. The parachute is the plastic sheet with the strings attached. So much for the obvious bits.

The tiniest tube (it looks like a drinking straw) is the launch lug and it's used to steady the rocket on the launch rod. The length of elastic is the shock cord, remember I recommended replacing it with a longer piece bought at the store. The two cardboard disks, the medium sized tube and black ring will be put together with that little metal strip and become the motor mount.

Pre-Assembly

Using your x-acto knife, carefully cut the fins out of the balsa sheet. They're die cut and held in by just a few short bits of wood. If you want to, you can gently sand the fins (with the grain) with the fine sandpaper before freeing them. Make the same kinds of cuts to remove the smaller middle circles from the cardboard disks. Finally, you may need to open the inside of the squared-off loop at the bottom of the nose cone (see the picture). Do all of these carefully, and watch for the sharp knife.



Make sure the fins fit the slots in the body tube. Sand them lightly if needed to ensure a smooth fit.

The following steps are completely optional.

Using the sandpaper, sand the seam on the plastic nose cone until it disappears. This isn't a quick process, but it does make for a much nicer looking end result.

Lightly sand the entire body tube until you've scuffed the shine off. Don't sand too much, the purpose here is to remove the glassine layer, which will make for a stronger bond between the glue and the paper tube underneath.

Take some of the Fill'n'Finish and thin it with water until it's about the consistency of pancake batter. Slather it on the body tube (I use my finger) and work it into the spiral groove. You won't need much, and most of what you use will be sanded away. Let it dry (it's pretty quick) and then lightly sand. The Fill'n'Finish sands easily, and when you get done there should be no spiral groove left. Repeat if you need to.

Use the same thinned Fill'n'Finish to fill the grain of the balsa fins. Keep the coats very very light, and sand between coats when dry. When you do the fins, do both sides at once, because the balsa will warp slightly and this will help even it out. The warp will straighten out when both sides are dry.

The reason for all this filling and sanding is because the smoother the surface, the less drag which makes for a higher flying rocket. I don't do it for every rocket, but I do take the time for most of them. The paint job looks much nicer on the smooth finished surface too.

Questions Answered (from previous posts)

What is a "fishing swivel?" Also known as snap swivels, they're used to prevent the fishing line from twisting. They have a small loop on one end and a large loop on the other end that opens like an old fashioned safety pin. Here's a (not great) picture of a few, and like I said, you'll only need one, and it's optional. Also in the picture you can see the package of sewing elastic, the glue and Fill'n'Finish, and an x-acto knife.



This is our rocket so far, after sanding the nosecone seams smooth and filling the spiral grooves on the body tube. Total sanding time was maybe 20 minutes. If you did those steps, you'll notice that the tube is a little fuzzy. Don't worry about that, because we'll smooth it out when we spray primer. I also had to spend a few minutes sanding the tabs on the fins so that they would slide easily into the slots. Nothing is glued together yet.



You may have noticed that the fin tabs have a small slice trimmed out at the bottom. This shallow notch fits over the black ring of the motor mount. This particular rocket boasts a nice bit of engineering because everything fits together and reinforces itself, making for robust construction. In fact, although we'll be flying this bird stock on B and C motors, I've seen the same kit strengthened and modified to fly on I motors (128 times more powerful)!

Now, I'd like to talk about what actually happens during the flight, and some of the basic aerodynamics involved.

Model rockets are set up on a 'launch rod', which ensures that the rocket stays straight until the rocket is moving fast enough for the fins to keep it stable. A good way to picture how the fins work is to compare it to a weathervane, and how it always points into the wind. When a rocket is moving through the air, its flight through the air provides the 'wind' that the fins work with.

Everyone has stuck their hand outside a car window at speed and felt the rush of air. When you keep your hand flat to the ground, the air moves smoothly past it, but if you try to cup your hand against the wind, then the wind pushes against it. The fins work in the exact same way, and it's this push that causes the rocket to stay straight.

The main effect of this is that the straighter the flight, the less drag the rocket has to overcome and the higher it will go. I'll go into other aspects of this as we go.

Next time, we start gluing things together!

And as always, leave questions in the comments. Thanks!

Building A Model Rocket - part 1

We're going to start a series of posts where I'll build a basic model rocket kit online. The idea is to show the process step by step, including pictures and passing along tips and tricks that I've learned along the way, while you follow along and build your own rocket.

Please feel free to ask questions as we progress, and hopefully we'll see some pictures as folks build and launch their own rockets.

Introduction

The rocket we're going to build is the Estes Fat Boy (see below). You used to be able to get this rocket in the toy section of WalMart, look for model rocket kits near the car model kits. You can also find it in some craft stores and hobby shops, sometimes in other packaging like a bag or box instead of the plastic bubble-package pictured, but it will probably cost a little more. If you'd like to build along and can't find the Fat Boy, you can get something similar because the basic steps will be the same. The Baby Bertha or Alpha would also be good choices, although most any Estes rocket kit will do.



Materials

Now is also the time to gather building materials. If I mention a specific brand, it's because I've used it and know it works. There are all kinds of products out there that'll work just as well.

You're going to need an x-acto knife (or equivalent, you could get by with a single-edge razor blade). You'll also need some yellow or white glue. I recommend Elmer's carpenters glue, if you get the exterior stuff it's gelled and doesn't run and drip nearly as much (it's also brownish). You can also use Eileen's Tacky Glue, TiteBond, white school glue, or anything similar.

The only other must-have will be a pencil.

The following things aren't strictly necessary, but if you use any or all of them you'll have a nicer looking and better flying rocket. They're completely optional, and I'll note when to use them if you want to.

I highly recommend that you get a pack of sewing elastic. You want to get the flat 1/8" wide stuff, and it'll probably be 3 yards long. WalMart sells it for about a dollar, back in the sewing department.

Super-fine sandpaper, at least 220 grit (the higher the number, the finer the grit). You can find this in the hardware department in sheets, or small pads of it in the craft section. WalMart sells an assortment from 3M called 'wet or dry' sanding pack that contains two sheets of 220, two of 320 and a sheet of 400 grit.

Elmer's Fill'n'Finish. Also found in the hardware department, get the smallest tub of this. If they have more than one kind with similar names, hold a tub of each in either hand and pick the lightest weight one. We'll use this to fill the grain in the balsa wood fins and the spirals in the rocket body. You could use a lightweight spackle too.

Fishing swivel. This makes attaching the parachute easier. Don't buy a package of these, but use one if you can borrow it or already have one in your tackle box.

You can wait to get primer and paint, and I'll talk more about it later. Here's a little about it up front though.

Spray primer. I use Rustoleum sandable primer, it comes in white, gray, or even black. Get whatever they have.

Spray paint. Rustoleum or Krylon is what I use. Get whatever colors you want to use. The little cans of Testors paint near the models are cool colors, but very expensive for their size.

Masking tape. You'll need a roll of 1/2" tape if you want to paint your rocket with more than one color.

Next up, we'll take a look at the various parts of the kit and do some pre-assembly work.

Box Hockey - Part 4 (Final)

Here's the final part of our series to build your own box hockey game. If you have any questions, feel free to leave 'em in the comments and I'll answer them as soon as I can.

Previous Box Hockey posts:

Box Hockey - Part 1
Box Hockey - Part 2
Box Hockey - Part 3

Finishing Touches
Ok, in the first three parts we built the main part of the box hockey table, and all that's left is a few little finishing details and some rules to play.

Using the leftover scrap hardboard, cut out two paddles and six triangles as shown in the diagram below. Sand the edges lightly to smooth them out.



The paddles are what you use to hit the checker puck with. The triangles are a later addition because sometimes the puck slid directly into a goal, often hitting the back wall and then popping back out. When the puck is moving fast enough, it's hard to tell if a goal was scored or not, so the triangles deflect the moving puck and prevent arguments. Use white glue or hot glue to fasten them into place against the back wall behind each goal slot.



Use a yardstick or tape measure to figure out the center line of the board, and mark it with a sharpie or other permanent marker.

That's it! If you want, you can flip the board over and mark or paint a checkerboard onto the bottom, we usually add a simple backgammon board too.

Box Hockey Rules
These are all suggestions based on what works for us. House rules are common, and on the playground it's not unusual for the winner to call special rules for the next game. The terms puck and checker are used interchangably.

The two side goals (bigger) are worth 1 point each, the middle, smaller goal is 3 points. The puck doesn't have to completely go through the slot for it to be a goal. We score the point if it breaks the plane of the back of the slot (slide the paddle along the back of the slot board, and if the checker moves, then scoooooore!

Game ends when one player scores 11 or 15 or 21 (decide at the start). Skunks are 7-0 or 11-1 scores.

Decide who goes first by flipping the checker (heads or tails) or by putting the puck on the center line and both players trying to hit it on the count of 3. Or just let the younger player have it first.

You can only hit the puck if it's on your side of the center line.

You can't touch the puck with anything but your paddle.

Have fun. No getting mad.

Easy Peasy!

I'd really love to hear if you make a box hockey for yourself, drop me a line if you do.

Box Hockey - Part 3

Click on these links for part 1 and for part 2 of the series.

Now we'll start constructing the frame. Cut out the end and side pieces - two of each - and square up the ends. Test fit the pieces together and do a measurement from one corner to the opposite corner on the other side. Each diagonal measurement should be the same or nearly so. If they are, then your frame will be squared up correctly.

Here's where a drill will come in handy and save you some blisters. You should drill pilot holes for the screws that hold these bits together. Countersink the holes too if you want, it will look neater and you can use a little wood putty to fill the holes once the screws are in place. You can google 'pilot hole' and 'countersink' for details if you don't know what those are. The picture shows what I mean, for those two light colored dots on the end are where the screws and putty are. In it we're looking up from below and can see where the bottom will be nailed into place.



When you drive the screws, put a thin smear of the glue on the wood where it joins together, then finish tightening the screws. Use a damp rag to wipe up any glue that squeezes out.

You can also (barely) see in the picture that I used finishing nails to attach the goal boards into place (right side, three light dots). The goal board is positioned 3 1/2 inches in front of the end boards. Countersink the nails and use a little wood putty again to fill the holes. Let the wood putty dry.

This is what the finished frame looks like, looking from one end to the other.



Lay the assembled frame on top of the hardboard and, using a pencil, trace along the outside of the frame to mark the cuts needed for the bottom of the box hockey game. Make sure you use the corner of the hardboard as one reference point, because that will ensure that you get two straight edges - one end and one side. Set the hardboard aside for now, we'll get to that in a little bit.

Cut a length of leftover wood about four inches long, wrap a piece of medium grit sandpaper around it, and use it to sand the frame smooth. Lightly round the edges and corners too. Always sand with the grain of the wood (long ways along the boards). Once everything is sanded, do it again with a piece of fine sandpaper. Sanding by hand is a pain in the butt, but it really makes the finished project look much nicer. I suggest getting zen with it, grasshopper.

Before you attach the bottom, go ahead and apply the finish of your choice to the frame. You can paint it, use varnish or tung oil, or for maximum protection use polyurethane. You can apply the polyurethane with those disposable foam brushes, just keep the coats thin to avoid big runs in the finish. If you want, you can sand the frame between dried coats with fine steel wool, that will really smooth out the finish. Follow the directions on the can for timing between coats and cleanup. Let everything dry thoroughly.

Cut out the rectangular hardboard bottom. Save the leftover hardboard, we'll be using it for the rest of the pieces. Flip the frame upside down, then place the hardboard with the smoothest side down on top of the frame. Starting in one corner, fasten the hardboard bottom to the frame using the small nails (panelling nails work well for this), spacing them every four inches or so.

Next time, we'll finish up the game board, cut out the paddles, and I'll talk about the rules we used to use.

Box Hockey posts:

Box Hockey - Part 1
Box Hockey - Part 2
Box Hockey - Part 4

Box Hockey - Part 2

See Part 1 here.

Building a Box Hockey game is about as simple as it gets. As I said in the original post, the woodworking skills are basic and power tools are helpful but not necessary.

Here's what you'll need from the hardware store:
(3) 1"x4"x6' pine -or- (2) 1"x4"x8' pine
(1) 2'x4' hardboard (1 smooth side)
(16) 1.5"x#6 flathead wood screws
(1) pkg mixed grit sandpaper (we'll use medium and fine)
(1) box small flathead brads (~5/8" long)
(1) small can of polyurethane
(1) 1" paintbrush

Tools and supplies needed:
Saw
Screwdriver
Drill and 1/16" or 3/32" bit (this will make things so much easier)
Elmers white or yellow glue or equivalent (optional but recommended)
Hammer
Straightedge
Ruler, yardstick or measuring tape
Pencil

Buying wood
Look for straight pieces without splits or chewed up edges. A few knots are ok, as long as they're tight and won't readily fall out. It's ok to pick through the rack of lumber to find just the right pieces, so be picky.

When you're looking at a piece, rest one end on the ground and sight down the length of it as if you were aiming a rifle. This will make obvious any warping, bowing, or twisting in the wood. You don't want that, get the straightest pieces possible. Look at it on edge, then swap the board end-for-end and look again. It may be necessary to buy an extra piece or two in order to get enough straight wood, since some boards might be perfect for half or two-thirds their length and then get funky. Since the boards should only be a few bucks each, it's worth the money to get good wood right up front.

Measurements - Frame
The frame of the Box Hockey game is made of 1"x4" pine. You'll need to cut 2 sides (42.5" long), 2 ends (22" long), and 2 goal boards (20.5" long). Cutting rabbets and dados will make the frame stronger, and if you know what that means then you can adjust the measurements on your own.



The goal boards have three goal openings cut into them. The outer two are 3" wide and start 3" from the ends, the middle one is 2.5" wide and sits 3" from the side goals. Make them tall enough to let a checker slide through (at least 1/2"), ours are 1" tall. You can see what I'm talking about on the diagram above (it's not to scale).

Next up, part 3 - pictures and finishing.

Box Hockey posts:

Box Hockey - Part 1
Box Hockey - Part 3
Box Hockey - Part 4

Box Hockey - Part 1

When I was a youngster, one way we filled our summer days was by going to the local elementary school for "Rec". Rec was shortspeak for "Recreation Services" and it was a program sponsored by our school district. Basically, for a few hours a day, someone (usually a college kid earning some pocket money) would sign out kickballs and jump ropes and games. There would be organized activities like bike races and weenie roasts and marble tournaments. I fondly recall heading up to the school to find out who was there and what was going on. It was one of the 'mixing bowls' of the area, because otherwise groups of kids mostly hung around together based on what street they lived on.

Some days it was just too darn hot to do anything. Even marbles sucked, because the best dirt beds for that were in full sun, and nobody felt like frying their brains.

That's when the board games would come out. Alongside the playgrougd were several fixed benches, shaded by the buildings and close to the cool bricks of the school wall. Looking like birds lined up on a telephone wire, we were grouped up in various ways as we played the games. Parcheesi (ick), Sorry and Chinese Checkers, Mandala (we called it something else though), and my personal favorite: Box Hockey*.

Box Hockey was the low-tech version of Air Hockey. In fact, to that point we had never heard of Air Hockey. Play is similar, and so is the speed of it, if only because the 'rink' is smaller.

The puck was a regular ol' checker, and the paddles were wedge-shaped pieces of hardboard. Each end had three goals, larger ones on each side worth one point, and a smaller one smack in the middle worth three points. Games went to 11 or 15 or 21, and there was usually someone hovering nearby with dibs on the next game.

When my kids were that age, I built our own Box Hockey game. It proved to be a hit, and I built several more over the years to give away as gifts. On the underside we put a checkerboard and backgammon board, and just flipped the hockey rink to play those. We'd usually include a set of checkers, some dice, and if the child was old enough a set of chess pieces.

So that's what we're going to do this go-round of "Build It", we're going to build a Box Hockey set. It makes a great birthday gift, or save it as a surprise for those heat-wave days coming up. It's also a great family project, simple enough to have the little ones pitch in. It makes it more special when they help.

If you've never done any woodworking, no worries. The skills are basic, and power tools will speed things along but aren't at all necessary. The materials are readily available and inexpensive. I estimate the cost as around $40.00, which isn't bad for a from-the-heart gift that will last for years.

Next up, a detailed parts and measurement list.

*There are other versions of Box Hockey out there, including one that sits on the floor and the players stand on either side and use sticks to move the puck or ball into the opponent's goal. That variation may become a future "Build It" project.

Box Hockey posts:

Box Hockey - Part 2
Box Hockey - Part 3
Box Hockey - Part 4

Just 25?

A while back, Victor posted this quote:

A human being should be able to change a diaper, plan an invasion, butcher a hog, conn a ship, design a building, write a sonnet, balance accounts, build a wall, set a bone, comfort the dying, take orders, give orders, cooperate, act alone, solve equations, analyze a new problem, pitch manure, program a computer, cook a tasty meal, fight efficiently, die gallantly. Specialization is for insects.- Robert A. Heinlein

In that same vein, Popular Mechanics has listed 25 skills that every man (and in my opinion every woman) should be able to do. I can do all except CPR and clean a bolt-action rifle. The October issue tells you how to do each one - should you not know.

Personally, I think that Heinlein's list is more comprehensive (with some of JenLars's corrections.

Science at home: Build your own nanotechnology lab

Some of the problems with pursuing modern science at home - or in a school - (particularly electronics or the study of matter at the atomic scale) is that the equipment to be able to see the effects of that scale can cost so much!

Well, here are instructions on making two pieces of equipment used in modern science.
First, the oscilloscope (with a nice history of oscilloscopes to boot):

The oscilloscope is still one of the most important measurement tools of the electronic engineer. With the advent of the often very reasonably priced USB scopes, such an instrument is now within reach of every body.

Second, once you have the oscilloscope, you can build your own scanning tunneling microscope (a key tool in nanotechnology) that is able to resolve atoms:

The goal of this project is to build a simple STM that can resolve atoms, with a cost of materials less than $100.00 excluding oscilloscope. My real goal here is to provide a base of information so experimenters and students could build a simple STM. Typical piezo tubes used in tube scanners of commercial scanning probe microscopes cost in the range of $200 - $800 and operate with several hundred volts applied to the scanner. This design uses a unimorph disk scanner to reduce the cost and avoid using any high voltage. The Piezo element is commonly available and this particular one costs $1.80. The control voltages are so low that two 9-volt batteries can power the control electronics.

Simple Rubberband Guns

As kids, we used to make these as needed every summer, although occasionally someone would fashion a more elaborate one and keep it from year to year.

And no, none of us ever put an eye out with one of these. Then again, we were bright enough not to intentionally aim at the face. We also did a lot of target shooting with 'em. That's what I recommend: target shooting at cans or flies or plastic army men.

Materials
Wood - length of broomstick or dowel, or a 1"x2" or even a 2"x4". Whatever you use, you need a piece about 12" long (more for a 2"x4" rifle).
Clothespins - tradition says to use the wooden spring type, but the plastic ones will work just fine. The simplest gun uses one, we usually used at least two. They come in bags of 100 or more, so borrow from a neighbor if you don't have your own. Or make lots of guns, you politically incorrect brute.
Rubberbands - in our house, we kept rubberbands around the doorknob on the furnace closet, and had plenty because you got one with every newspaper delivered. They're cheap, so don't go mugging the paperboy for his.

How To
Take sandpaper and round off any sharp edges to eliminate wood splinters. Use a file to cut a shallow "V" notch in the end of the wood. Use one rubber band to fasten a clothespin to the wood on the opposite end of the wood from the notch. That's it!
Here's a picture of a fancy store-bought model that works exactly this way. It's a good view of the clothespin and notch setup.

To Use
Hook a rubber band around the end of the wood so it's in the notch. Stretch it back with one hand, use the other to open the clothespin and catch the rubberband. When ready to shoot, press on the clothespin and zing!

You can cut out pistol or rifle shapes from the wood, mount multiple clothespins (and make extra notches), and do all kinds of custom coolness with the basic design. Often we'd grab a piece of scrap wood, use a rock to gouge out the notch, grab a clothespin from the clothesline out back and a handfull of rubberbands from the doorknob. Within minutes you had something that worked, and sometimes the ugliest thing was the straightest shooter (my best was a piece of old yellow broomstick with two clothespins attached). Showing up with a store-bought rubberband gun was tolerated - barely - mainly because we'd closely examine it to see how they managed multiple shots if it worked that way.

Some of the most worthwhile ways to spend 5 minutes

A very excellent website where Popular Science is taking its HOW 2.0 projects and turning them into quick 5 minute videos. Up right now are a use for old, died out hard drives, how to make a coffee can cellphone antenna, and making a bottle cap tripod.

Enjoy!

Rattlesnake Eggs

Imagine showing a mysterious envelope to your friends. On the outside of the envelope are warnings about the contents, letting people know that whatever is inside is very dangerous. The envelope isn't flat, there is obviously something in there. You tell everyone that the envelope contains rattlesnake eggs, and if they're very careful they can take a peek. You lift the flap, you hold the envelope out, they bend close to peer inside, and you carefully open the envelope...

...and your friends jump like crazy when a loud rattling sound buzzes from inside the envelope!

When I was growing up, every few years I would make this simple practical joke and scare a brand new group of schoolmates. Nobody ever seemed to have heard of it, which made it all the better because they weren't expecting it.

(Yay! More of Ted's cheesy diagrams!)

Materials:

1. A mailing envelope.
2. A wire coat hanger.
3. A rubber band.
4. A large coat button.



The first thing to do is to cut the hook end of the coat hanger off, as shown in step 1 over on the right. The easiest way to do it is to use a pair of snips or dykes (cutting pliers), but if you must you can just bend the soft metal of the hanger hook back and forth until it breaks. Be careful, the edges might be sharp!

Next, thread the rubber band through the button holes as shown in step 2.

The only fiddly bit is the size of the button. Too small, and it won't spin right to make the noise, too big and you'll have the same problem. Look through mom's button box and find a few to try.

The ends of the rubber bands go over the ends of the wire hook. Then you just wind up the button until the rubber bands are twisted tight. If you let go of the button now, you'll see how it spins rapidly. Inside the envelope, the button will snap against the paper sides which creates the loud buzzing sound that startles people.

Don't forget to write dire warnings on the outside of the envelope! Things like "Danger: Rattlesnake Eggs" and "Do Not Crush: Rattlesnake Eggs" are good. Skulls and Crossbones are always fashionable.

To use, wind up the button and slip it inside the envelope. Hold the sides so the button doesn't move and give away the trick until you're ready. You can even peek inside yourself while holding the button. When everyone is looking inside, slightly open the envelope and let it buzz!

Drawing water up a hill

I like thinking about the world before electronics. Not that I'd like to return to those days, but the machines invented to perform tasks in the world of mechanics are sheer brilliance. Probably topping the list of really cool mechanical machines is the machine known as Archimedes Screw.

Archimedes Screw enables water to be drawn up hill (or to irrigate some Hanging Gardens that might be hanging around the city of Babylon). How does it work? Well, you turn the screw and the water flows up the screw. The simple machines that you learned about in elementary school? Well, here is where they matter. The screw is an inclined plane wrapped around a cylinder. As the screw turns, it scoops up water. This water is pushed up the incline (around the cylinder) until it finally pours out from the top, feeding an irrigation system.


Does such a mechanical system still have value in today's world? Of course! Not only is it fun to create your own irrigation system from the local creek (a fun weekend project), but such systems are of wide use in the world - from the developed world (where Archimedes Screws are used in sewage treatment plants - like the one in Memphis, TN, shown above) to the undeveloped world needing cheap, available irrigation (shown below)



For more on Archimedes Screw (and his other wonderful inventions), check this out.

How High Is That?

If you want to figure out how tall something is (like a house or tree), or how high it goes (like a rocket or balloon), there’s a simple and inexpensive way to get a fair estimate.

You’ll need a couple things for this, but they’re easy to find and you probably already have them around the house. Find a protractor and a rectangular piece of cardboard bigger than the protractor. You’ll also need a push pin, some string and a weight of some kind (I used a fishing sinker).

First, let’s make a simple theodolite, which is a tool used to measure vertical angles. Take the cardboard and using the push pin, fasten the protractor to it so that the flat edge of the protractor runs along the top of the cardboard. Tie the weight to one end of the string and the other end to the pin. This way, when you tilt the cardboard you can read the angle by seeing where the string hangs past the protractor.

The other thing you’ll need is a tangent table, which can be found in any trigonometry textbook. That’s right, you’re using trigonometry for this! Use the one below, or find one to your liking, they're all the same (click it and it gets bigger).

Still with me? Good! Believe me, this is simple. In fact, this explanation takes longer than the process. The figure below shows the basic concept of determining height or altitude:

Take the theodolite and stand a known distance from what you’re trying to measure. In the diagram, it's where the black and blue lines meet. This distance is the baseline, and the farther the better (as long as you can see the top of the thing you’re measuring). For instance, say you’re going to measure the altitude of a model rocket, and you’re launching from a football field. The tracker is on one goal line, 300 feet (100 yards) away from the launch pad on the other goal line. When the rocket launches, the tracker follows the rocket with the theodolite until the rocket reaches apogee (it's highest point). The angle is read (where the string marks it on the protractor), and this angle is written down.

Time for some simple math. The formula is on the diagram. Look up the tangent for the angle on the table, multiply that number by the baseline, and that is the altitude in feet. Simple!!!
An example: baseline is 300 feet and your measured angle is 40 degrees. The tangent for 40 degrees is .839, so 300 * .839 = 251.7 feet.

This technique works great for things that stand still or go straight up, but the measurement will be off if there’s any horizontal movement. Using our model rocket example again, if the rocket curves towards you on the way up, then your measured angle will increase and the calculated altitude will be too high. One way to compensate for this is to have two people with theodolites standing at 90 degrees from each other (imagine a rocket launching from home plate on a baseball diamond and trackers standing on first and third bases). You can average their measurements and get a pretty good estimate of the correct height.

You can also make a sturdier theodolite by replacing the cardboard with a length of wood or broomstick. Screw the protractor into the side of the wood, hold the theodolite like a rifle and sight along the length of it to get your measurement. You can drive a couple of finishing nails into the top of the wood to help with your sighting if you want, but it's not strictly necessary.

So, how high is the tallest tree in your neighborhood?

Spider Houses

People have houses. Dogs have houses. Birds have houses. Even butterflies and bats have houses. Let's learn how to build a spider house.

Why in the world would you build a spider house? Firstly, spiders are fascinating creatures and it's neat to be able to go outside and watch one doing its spider-thing in a frame that you built. Secondly, spiders eat a lot of pesky insects, including some that might be eating the plants in your vegetable or flower garden.


Materials Needed:


Thin wood such as grapestake. What you're looking for is wood about the size of what yardsticks are made out of, something about one to two inches wide and one-quarter inch or less thick. Grapestakes are cheap, come in bundles and are about six feet long. Perfect.

Wood glue. Waterproof or exterior is better, but even hot-melt glue will work.

Saw

Ruler

String or twine. You'll only need this if you want to hang your spider house instead of sticking it into the ground.

Directions:

Before you begin, cut out four pieces of wood about 12 inches long. Next, cut out two pieces about 3 inches long. A hand saw works fine for this. Save the rest of the grapestake, you'll use it later.

1. Put two of the 12 inch pieces next to each other as shown below. Put a good spot of glue on each end, where the gray circles are on the diagram.


2. Take the other two 12 inch pieces and lay them across the glue spots as shown on the left, to make a square. Clamp the corners or place something heavy on them (make sure to clean up any glue that oozes out!) and let the glue dry.



3. Those two short pieces that you cut will be attached to the square frame so they make a little nook for the spider. This gives the spider protection from the rain and a place to hide when it feels threatened.

4. Time for more spots of glue. The spot shown is where you'll put the glue on each side (front and back) of the frame.

5. Glue the two short pieces to the frame as shown. The front one is sideways and the rear one is on the other side of the frame and runs in the same direction. This creates the little hidey-hole. Clamp or weight down and let dry.


Next, decide how you want to display your spider house. You can glue the remaining length of grapestake to the bottom corner and stick it in the ground in your garden, or you can tie some string or twine through one corner and hang it. Either way, there should be some protection from the wind and elements or spiders will find it unsuitable and look elsewhere to live. Like inside your house.

This makes a fairly large frame, and all of the measurements are flexible. Make smaller ones if you'd like, even popsicle sticks can be used (although you'd likely have smaller spiders take up residence there). If you build something bigger than about three feet square, I don't want to know what decides to live there.

After you place your spider houses, wait a couple of days and you'll see webs being built inside the frames.

Leave a comment and let us know how your spider houses are doing! Or email us at DangerousBlog@gmail.com and send pictures, because we looooove spiders!