Even the ugliest jigsaw puzzles can be enthralling. When you find the perfect spot for that one piece, for a second it almost seems like life has meaning. Angsty existential musings aside, puzzles can also be goshdarned fun, and they present tons of creative possibilities (puz-3d,tesselated puzzles, etc), and so I wondered: why aren't puzzles more popular among crafters and DIY-type creative persons? It turns out the reason is simple: using traditional methods, they are super hard to make!

To render a good, sturdy puzzle out of wood or cardboard, you need either a puzzle-making die, a laser cutter, or a really nice scrollsaw, none of which are exactly affordable or kid-safe. Of course, you could just buy a "make your own puzzle" kit like the one advertised here, but with those kits you won't get to make your own shapes, the images won't turn out photo-quality, and besides, anything that comes in a pre-packaged kit will hardly be DIY.

Will man ever harness the crafty power of the DIY puzzle? (answer: yes)
I was in a bind for my own puzzle-intensive project, so I had to figure out how to crank out puzzles easily and on the cheap. So, after much experimenting, I stumbled into a way of making sharp-looking, tactile, photo-quality jigsaw puzzles using thick sheets of foamcore styrofoam and a hot-wire-cutter. Its so easy you could make one in a single afternoon, and its safe for ages 12 and up (so says the hot-wire-cutter packaging -- I would think younger than that is still ok). And since you can buy foam in thick sheets (up to 2"), the pieces always end up satisfyingly chunky.

If you follow along with this instructable, you will learn how to make cheap, slick looking puzzles that are also enjoyable to play with. Once you get the hang of it, you can decide if you want to step it up a notch and build your own more professional hot-wire foam cutter, like I did, or invest in your own cnc paper cutter to prepare the pieces, also a good idea if you plan to do this a lot.

Materials:
Here are the materials you will need, all of which can be found at AC Moore or Michaels:
Styrofoam-Safe Spray Adhesive (from 3M)
Zip-Ties (zip ties are the new duct-tape)
A thin piece of plywood or matteboard
X-Acto Knife and Cutting Mat
Styro-Wonder-Cutter from AC moore or Michaels (don't get the "styro-cutter plus" - its junk)
A single D battery.
A ball of aluminum foil.
Some photo paper and a printer
foam core (1/2" thick, white or black)
A roll of duct tape (duct tape is the new zip ties)

Step 1: Prepare the Image

Print an image on photo paper or draw a design on cardstock. If you drew the design with pencil or pen, use a spray fixative such as Krylon Preserve It! to prevent smudges on artwork. If you are printing an image out, you may want to find a printer that can do 11x17 prints -- most office buildings have these. (You can also print the image out on several pieces of paper, if you are smart about how they overlap.)

Now, cut out the puzzle shapes with an X-acto blade. Stay traditional or get creative. Cut out someone's name or trace shapes that appear in the image. In the images shown here, I'm tracing the outlines of the animals that appear in the image (I'm using an Escher print called "Mosaic II").

A word about child safety:
If the puzzle is intended for small children, A rule of thumb is that the finished puzzle piece should not come close to fitting into a double shot glass -- this is the size of a small child's windpipe. I wouldn't recommend this technique for very small childen, anyway, since they may chew/break the puzzle pieces into chokable chunks.

Step 2: Prepare the Raw Foam

The next step is to isolate the foamy goodness from the gooey center of a 1/4" or 1/2" thick sheet of foamcore. You need to remove almost all traces of paper, and do it without creating too many nicks and burrs in the foam material. The paper on black Elmer's Bienfang foamcore was very easy to peel off; while the paper on the white foam core I tried needed some coaxing: soak it in water till pulpy and then roll the paper pulp into wads with your finger tips.

You can also get raw foam, without the paper backing, at the hardware store in the insulation section. It comes in rad colors like baby-blue and pink, and in sheets up to 2" thick. These foams will also work for this project, but don't use yellow couch foam or any foam not explicitly labeled "styrofoam" "XPS," "EPS," or "polystyrene." You can also use Styrofoam brand styrofoam, but it is kinda brittle.

Step 3: Attach Paper Pieces to Foam

Spray some of the styrofoam-safe adhesive on to the foam (test a small patch first). While it is still wet, smear it around with the back of one of your paper puzzle pieces. After both the piece and the foam are evenly coated, wait a minute for the glue to get tacky, then stick the two together (design side up).

Next, I use a roll of duct tape as a rolling pin to smooth the pieces down. However, the duct tape will get glue on it unless you put a piece of scrap paper down first on top of your pieces, then roll on top of that. When you are done rolling, the glue will still be wet enough for you to peel the scrap paper back up and off your design.

I just described how to attach a single puzzle piece to the foam backing, but you probably are going to want to perform these steps on several pieces at a time. Note that the pieces don't have to be arranged in puzzle formation: ie the puzzle shards don't have to be touching, or even close to each other, for that matter; just slap them on there.

Step 4: Prepare the Wire-Cutter

Follow the instructions on the back of the Styro Wonder Cutter to assemble. I found that the Styro Wonder Cutter is a little too hot for my taste, so I replaced one of the D-cell batteries with a balled up piece of aluminum foil. This effectively removes one of the batteries from the circuit, and reduces the voltage across the cutting wire.

Another rule about the heat of the wire is: the shorter the cutting wire, the hotter it will get. I found that shorter was better. Make sure the wire makes a nice "plink" sound when you pluck it. If not, the wire is not tight enough.

Step 5: Create a Puzzle Cutting Jig

Theory of operation:

The jig for cutting out puzzles is the same setup as a scroll-saw, except a heated wire, not a blade, is the cutting element. The wire is hot enough to cut/melt through the foam, but not hot enough to pass through the paper puzzle pieces. So, the paper acts as a template to create perfectly shaped foam puzzle pieces, with your design on top.

Assembly:
Find a table with legs that are flush with the table top.  A perfect example is Ikea's environmentally-friendly and absurdly affordable Lack (it costs less than the foamcore!).

Attach the Styro Wonder Cutter to a leg of the table with zip ties. You want the cutting wire to stick up perpendicular to the table top. If it is not perpendicular, remove the wire and do some creative bending of the metal armature.  Use a box with square sides to confirm everything is square.

8. Next, drill a one-inch hole in a sheetof plywood or a matte board. This will be your worksurface.  Unhook the cutting wire from the cutter and thread it through the hole you made, then clamp the sheet to the table.  You should now have a sturdy (ish) worksurface with a hole in it, and a wire sticking up out of that hole at 90 degrees.

IMPORTANT:  Position this whole setup outside or next to a window, and use a mighty fan to blow away fumes.

Step 6: Cut Out the Puzzle Pieces

Guide the wire cutter through the styrofoam at a patient but steady pace, tracing out the paper shapes. The foam should resist, but cut smoothly. Don’t stall or the foam will melt. I find that a "support our troops" shape is best for negotiating sharp corners. Use a fan to control the ventilation -- definitely do all of this outside or near an open window. I wouldn't say the fumes are toxic, but I also wouldn't say that they are not not toxic, so be careful.

The fan can also be used as a fine adjustment of temperature. For example, if you find that the bottom of the foam pieces look melty and don't have sharp, clean edges, position the fan to blow more air underneath the cutter to cool down the wire there. Clean the wire with a paper towel if it collects debris.

If you for some reason run out of cutting wire (several spares are included with the kit) you can use guitar string, although I'm not sure which guage.

Step 7: Enjoy Your Beautiful Puzzle Pieces!

You are done
The pieces should now be cut out and should fit together easily... well, maybe not easily -- this is supposed to be a puzzle after all!

But wait! here is a hint to make your next puzzle even better:
(I left this step out of the original instructions just so nobody got confused that we were dealing with two different sets of identical puzzle pieces, but now that you know how everything works...)
Back in step one, we could have cut out two sets of puzzle pieces at the same time: one blank, one with the design on it. Then we could have had a second set of pieces to attach to the back of the puzzle pieces we just made. Man, that would have been nifty!

Step 8: Thanks

This instructable was written by Jack Zylkin from Hive76. Please visit www.hive76.org for some exciting upcoming events, and visit Jack's personal puzzle site, www.beeboobop.net, for items Jack hasn't quite got the nerve to sell yet (though you can make him an offer).

Thanks to Brian James Kirk and Holly Otterbein from Philadelphia City Paper for making an abridged version of this instructable for the folks in Philadelphia.

Also, thanks to my parents and my girlfriend Kelsey for their inexplicable patience with my puzzle obsession.

Thanks also to Far for supressing his DTs long enough to take some pictures.