Required Materials: Some thin walled plastic tubing (1 foot is plenty), Piezio Ignitor (from a spent lighter), 6 inches of #316 Stainless Steel TIG Welding Wire (any welding shop will give you a piece of scrap #316 stainless TIG wire), 9 volt battery connector with wires, Acorn Shaped plastic container (from any gumball junk machine), Soldering Gun, Plastic Cup, Casting Resin, needle nosed pliars

I would definitely read over the SciToys.com website before you begin this project with your child. They offer a LOT of good information and my version is just an attempt to simplify that project which they originally posted.

1. Tape your piezio ignitor up so that the casting resin can not enter the unit. Simple scotch tape around the openings should be all you need to apply. Some ignitors have no openings except for the top, so you're OK there if they don't.
2. Cut 2 small lengths of the TIG wire to be just long enough to push through your reaction chamber. Make them about 1/2 inch longer than necessary.
3. SMASH the 1 end of the TIG wire on a metal surface, with a hammer. You need to rough the end up so you can solder your 9 volt connector wire to it.
4. Solder your 9v connector wires to your TIG wires where you hammered them flat.
5. Trim the piezio wire tips. Make 1 wire very short. I recommend the bottom wire comming off of the ignitor. Keep it about 1 inch. Let the other one at about 4 inches.
6. Strip about 1/8 inch of the tip of each piezio wire and apply solder to keep the wires smooth and coated.
7. Drill your holes... 8 total. All holes should allow the thing going into them to fit SNUGLY!
8. The 2 large ones in the bottom are to accept the tubing.
9. The 4 small holes, are for your TIG wire. Push your TIG wire through one and out the other side. Use the needle nose pliars for this, don't touch the soldered spot or you may break your solder joint. SEE PICTURE!
10. The final 2 top holes are drilled at an angle to accept the piezio wires. SEE Picture. NOTE: you want the piezio wires to remain as far apart as possible. The closest point between the 2 wires anywhere, should be your spark gap. Keep it small enough to ensure the spark jumps, but not too small that a drop of water may get caught between the 2 wire tips.
11. The piezio ignitor is the last thing you adjust. It should be supported by the heavy piezio wires. I in fact pushed my piezio wires into the holes a bit, this is necessary for a snug fit. Don't just put the soldered part into the holes, push the wire's plastic coating in a tiny bit as well.
12. Insert your plastic tubes. These holes should be tight. Just push your tubes in a tiny bit, you don't want them into the case very far at all.
13. Now put your finished project (it should look just like mine) down into the cup. Center it all up and be sure that all holes are sealed. You don't want any resin getting into your explosion chamber or into your piezio ignitor.
14. Mix up your casting resin. I used 4 drops of catalyst per ounce of resin. Pour carefully and let dry overnight.