Fill your favorite nerd's stocking with Make's holiday gift guide

I've built a number of kits from Make and they're a great way to learn and hone your DIY electronics skills, with super-clear instructions. After the jump, I add my five additions to their list, with an eye toward encouraging the young hijinks-prone Makers-in-training on your list.

1. Super TV-B-Gone kit
$21.99
Okay, it's $2 over an Andrew Jackson, but if there's any way to get kids interested in electronics, it's with guaranteed mischief, like secretly turning off any TV in the area just before The Biggest Loser is revealed. But maybe give it to him after

2. Fire Piston kit
$20
I was just talking with our resident mad scientist Theo Gray about doing a column on fire pistons, a very cool way to start a fire with basically nothing but pressure.

3. MAKE: Warranty Voider - Leatherman "Squirt" E4 (electronics version)
$39.95
I just traded a Swiss Army Knife for one of these for my keychain (I got the non-branded pliers version, but a laser-etched Make logo is easily worth the extra dough) and already I want to void a warranty with it. And yes, I'm advocating giving a pocket knife to a kid—just teach him or her not to stab living things with it and they'll be fine. Pocket knives, like fire, are a crucial tool for encouraging tinkering.

4. Barrage Garage Vo1. 1 DVD"
$19.99
You can't go wrong with anything from DIY crazy man Bill Gurstelle, whose other projects feature titles like Backyard Balistics and Absinthe & Flamethrowers.

5. ReMake America T-shirt
$8
Remind everyone that tinkering, building, making and unmaking are part of the American spirit. Barack Obama himself says so.

Some of it I really do plan to use. Some of it I can't even identify.

Am I supposed to just assume my local Radio Shack will have my back? Not likely.

I was doing better, I really was, and then I visited the DeAnza flea market in Cupertino last year, and it all fell apart again. I don't know, maybe I'm beyond help. Check the photo gallery for some electronics-nerd eye candy, the detritus of my demon.

Some of it I really do plan to use. Some of it I can't even identify. And some is just fun to have around.

Fun with pressure vessels

There are several ways to put NPT (National Pipe Thread, which is a tapered, sealing thread used in plumbing; it is the US standard for pipe threads) in a drum, tank, or pressure vessel. The obvious is, of course, to use or adapt any threads already provided on the vessel. Another is to drill and tap a pipe-threaded hole, although this only works if the wall of the vessel is sufficiently thick to create enough threads; often it is not. A third is to use what's known as a through-wall fitting, which assembles around a hole drilled in the tank and does not require welding. These are rated for mild pressure and can be useful. And finally, there is the item pictured, a weld-on tank bung.

Assuming that you can weld an airtight seam, these are a great way to add threads to a tank or vessel. However, a strong note of caution applies: Do not even think about using these fittings unless you are a competent welder and versed in the risks of welding on pressure vessels. A pressure-vessel failure is not an event you want to be around.

If you are building a pneumatic cannon, you can pick a suitably sized pipe and weld a tank bung into one end of the pipe to create the perfect firing chamber. All of the pressure vessel risks and warnings stated above apply as well as the new risks of exploding windows, police, etc...

Again, the first to tell us in the comments what it is we're looking at here with the highest level of precision will win a Stanley FatMax 24-inch Level. Good luck!

UPDATE: It seems as if our use of the word "part" was misleading here. Think part as in "part used in the making of stuff" as opposed to part as in "part of a machine." Also, in reference to @GTO's comment, the hole in the center and the threads go all the way through. Keep up all the good guesses!

The motorized flyer packs into a compact package that can fit easily into an SUV or an airline's luggage compartment, and reassemble quickly. The ten-liter gas tank keeps Steinmetz aloft for 2 to 3 hours.

Visit Georgesteinmetz.com for more remarkable photography and details about the man and his craft.

[National Geographic, via The Awl]

The motorized flyer packs into a compact package that can fit easily into an SUV or an airline's luggage compartment, and reassemble quickly. The ten-liter gas tank keeps Steinmetz aloft for 2 to 3 hours.

Visit Georgesteinmetz.com for more remarkable photography and details about the man and his craft.

[National Geographic, via The Awl]

The best way to finish your steel and a link to my chemist ancestors

Paint hides all of the personality of the steel's mill finish and the details of the fabrication. Polyurethane adds a shiny layer that often doesn't look quite right. Wax presents a beautiful dull finish that looks a part of the metal itself and keeps moisture out. Since the wax is only a coating and doesn't actually bind with the steel, it must be periodically reapplied. But unless the piece is in a particularly brutal environment—like outside—the wax will typically last at least a few years.

People use all sorts of different waxes and concoctions for finishing steel, but I prefer Butcher's Wax for most of my projects. There are two versions, an amber wax and a clear "bowling alley wax."

The first step in applying a wax finish is to clean and dry the steel. I typically use mineral spirits to cut any grease or oil on the piece. We don't want to trap in any contaminants with the finish.

Gasses can be dissolved in metals, and water vapor is no exception. Before applying the finish, that moisture must be driven out or rust will form underneath the wax. I use a Mapp gas torch for this. As you heat the metal, a haze will appear. This is the moisture coming to the surface. As it evaporates, the haze will clear up. Move over the entire surface of the steel ntil it goes through this cycle.

It is best to apply the Butcher's Wax while the steel is still warm, but not too hot. The ideal temperature will melt the wax quickly, but will not boil it. If the part to be finished is large, start while the steel is still on the hot side, so that it will still be warm enough to melt the wax by the time the entire part is waxed. I use either a rag or a cheap paintbrush to apply the wax. Work the wax over the entire part and make sure everything is covered, but don't apply too thick of a layer. If you put down too much wax, you will pay for it in the next step.

After the piece cools, the wax will appear dull, which means it's time for buffing. Using a clean cloth, buff out all of this dull wax as if you were waxing a car. Thicker applications will take serious elbow grease while thin layers will buff out easily. When the wax has been sufficiently buffed, the dullness will be gone, replaced with a slight shine. The finished wax should feel smooth and slippery to the touch.

With that application of wax and just a bit of work, you will have applied a finish unrivaled by polyurethane that brings out the warmth, color, and texture of your metal work. When the finish begins to look thin, or if any surface rust appears, just clean (and abrade if necessary) the surface and add a new layer of wax.

The wax finish only forms a surface layer that adheres to the metal. Interestingly, oils will actually soak into metal and gasses will dissolve into metals. Here, from the June 27, 1930 issue of Time magazine, is a description of my chemist great-grandfather's research on the topic:

Speck of Gas. Engineers long ago learned that metals contain absorbed gases. Recently they learned that in lubrication the oil soaks into metal, oozes out when the machine operates (TIME, June 13). How deep into the metal does a gas go, skin-deep or throughout? Dr. Abraham Lincoln Marshall proved—with special heating, evacuating and analyzing devices —that gas thoroughly permeates metal. From a piece of molybdenum he extracted a speck of gas one-eighth the volume of a common pin, one 100-millionth of an ounce. Dr. Marshall found it a mixture of 43% carbon monoxide, 57% nitrogen.

Learn how to weild a plasma cutter like a pro and you can slice through steel like butter

In a previous Tool School post, we looked at oxy-acetylene cutting. Oxy-fuel cutting is great for thicker materials. But when it comes to thin materials, especially 0.25-inch and thinner, the plasma cutter shines. For the record, plasma cutting shines on thicker materials as well, but requires a bigger, more expensive machine. For the shop on a budget (and who isn't?), stick with oxy-fuel for the thick stuff and keep a small plasma cutter for thin materials. Also, while oxy-fuel cutting is limited to steel, plasma cutting can cut through any conductive material.

The plasma cutter works by using sophisticated electronics and a bit of hafnium, which releases electrons into the air very easily, to create a superhot plasma (ionized gas) at the tip and compressed air to blow that plasma through the material being cut. (Here's a good video on how plasma cutting works from machine-maker Thermal Dynamics.) Because of that, the heat applied to the part being cut remains far more localized than with oxy-fuel cutting. In practical terms, this means that thin metal is less likely to warp when plasma cut than when cut with oxy-fuel methods.

Safety:

As with the oxy-acetylene Tool School post, we need to address safety first. Plasma cutting generates hot sparks and slag (hot bits of melted metal), which means that all of the apparel guidelines that apply to welding and gas cutting apply here as well.

1. Apparel: Wear a protective jacket designed for welding. Wear pants made of a natural fiber without cuffs. Wear gloves. Protect any part of your body you don't want to touch hot bits of melted metal.

2. Eye Protection: Plasma cutting generates intense light. Wear shaded eye protection in the range of #7 to #9. Thicker materials call for a shade on the darker end of the range.

3. Environment: Hot sparks and slag will rain down from the cutting area. Make sure they can't fall onto anything they can ignite.

4. Ventilation: Plasma cutting produces gasses and airborne dust; have a way to evacuate them from the work area in short order.

5. Remember that no quick post online can convey all of the safety points needed to operate complex and dangerous tools. It is your responsibility to do your own research and to educate yourself as to the safety best practices. What is provided above is only a primer. Always make use of the best tool that you have available: common sense.

Cutting:

Plasma cutters are far easier to setup and use than oxy-fuel setups. There are really only two variables and they are related: The power level (the single dial on the machine) and how fast you move the torch. Given the same thickness of material, you can cut at a lower power level if you move the torch slower. Conversely, the torch can move faster at a higher power level. Unless the situation calls for a very narrow kerf (the width of the actual cut), it's generally easier to lean toward higher power settings, especially while still getting a feel for the equipment and the process.

I made a few sample cuts on 1/8-inch mild steel plate to show some common beginner problems. Comparing these cuts to yours should help to dial in your power settings and cutting speeds.

1. The power level was set way too low for the material, especially at the cutting speed used. The cut did not even penetrate all the way through the material. Remedy: Turn up the power and/or move the torch more slowly (probably both).

2. The power level used here was the same as that in cut #1, but the torch was moved very slowly. This is still not a good cut. The power level is just too low for the thickness of the material, as indicated by the buildup of slag on top of the piece next to the cut. I didn't put enough energy into the cut to blow the slag out the bottom. And slag on top of the cut is much harder to chip off than the slag on the bottom. Often it has to be ground off. Remedy: Turn up the juice.

3. The power level used here was higher. Technically speaking, it was too high for the material and cutting speed used. It works fine, but leaves a very wide kerf. The great thing about plasma cutting is that you don't really need to be that precise with the dial—just vary the torch speed accordingly. Remedy: Either do nothing, or turn down the power slightly.

4. This is the cut you want. The power was set higher than on cut #1 and lower than on cut #3. Approximately the same cutting speed was used in cuts 1, 3, and 4. The kerf is a reasonable size and there is no slag on top of the cut. Once you have dialed in the amount of power and the cutting speed to this point, all that is left to do is practice your hand eye coordination and learn some of the finer details. (Experts may want to share some of the tricks they've picked up over the years in the comments below.)

5. This cut was made with worn out consumables—torch tips, electrodes, cups—in the torch head. The cut is a bit rougher and, although it is hard to see in this picture, is angled rather than straight through the metal. The plasma jet has a tendency to go wherever it wants as the torch tip begins to wear. Remedy: Replacing the worn out parts will bring the cut back to the point of cut #4.

Cleanup:

After cutting, there will be slag on the back side of the cut, as in the picture below.

Resist the temptation to grind this off! If the cut was well executed, with the proper power settings and cutting speed, this slag should easily chip off with a cold chisel and hammer. Using the cold chisel will leave a far cleaner edge than grinding ever would and will also take far less time.

Cuts # 1-4 have been left untouched. The slag has been chipped from the back side of cut #5 to show the result. It took about 10 seconds.

While this may seem oversimplified, plasma cutting, like wire-feed welding, really is something you can pick up in an afternoon and start building your first project. Of course, like any DIY skill, there's almost no limit to how good you can get with enough practice and, if you're lucky enough to know some, tips from old pros. In the meantime, check out Miller's extensive plasma-cutting resources to learn more.

An old-school metal shaper makes it look easy

When the metal is flat, all is well. As in the tissue paper example, once a depression that constitutes a compound curve is made, the metal is going to form ripples. That extra metal needs to go somewhere. Through a specific way of supporting the work and hammering, sheet metal shapers drive the extra metal forming those ripples back into the sheet itself, making the surface area slightly smaller and the metal slightly thicker in the area being hammered. If this technique is done incorrectly, you'll simply chase the ripples all around the work piece, eventually flattening it back out, having wasted a lot of energy hammering. When it's done correctly, hammering actually makes the metal get thicker in the area being hammered, counter intuitive as that may seem.

Making bowls may not be all that interesting in and of itself, but this technique and the ability to form these compound curves is at the core of all sheet metal hand forming. This fellow makes it look easy: