Coiled blow dryer heating filament (Nichrome wire) screws (2 FLAT, 2 PHILIPS)
pieces of scrap wood (2x4, 1/2"x1/2", L:11.5")
electrical wires Any switch you have laying around (I used a household switch)
laptop power supply (mine is 19v 4.7A)
Spring (about 1/4"-1/2")
Optional thin aluminum plate
I used it mainly to make custom acrylic boxes or plastics for 18650 power supply (3S or 4S BMS with buck). I need it for making small custom boxes.
First, you prepare your wood and cut to desired length, nail it and set set the screews as shown on the pic. There is a calculator to find the right size of nichrome wire size, length and power supply (http://www.jacobs-online.biz/nichrome/NichromeCalc.html).
BUT since this is so simple, I just did trial and error and got lucky on my first try. Nichrome wire tends to stretch longer when it is heated that is why I put a spring at the end. I used a blow dryer heating filament nichrome wire which is coiled type so it could adjust to your needs--pull, strech, or cut it based on the power supply you will be using. The goal is to make a very slight glow so you can leave it on without worrying that it will burn out. IF your power supply is too weak, stretch it a little and cut a little at a time. Remember, give it some time and let it cool down before you touch the wire. The end loop of the spring makes it handy when streaching, sliding, and cutting.
No need for detail instrutionssince it is so simple and the dimension is on the materials list. There is also no polarity since it is nichrome wire.
Measure the exact rectanglar bottom of the box you like to make, add 1/2" to an inch on each side and cut the corners of each end as shown on the picture, then you are ready to bend. Line-up the area of the arylic on the wire, It takes about a minute plus a few seconds for a 1/6" acrylic to flex and bend. You can actually feel it getting flexible when it is ready. Bend it and use the wood corner to make a 90 degree bend. Hold it just a few seconds for it to cool down and stay in the 90 degree shape.
I got lucky to have some acrylic scraps from an old projection TV screen that I dismantled because it was too heavy for me to bring down stairs and dispose of. It actually came with 2 clear acrylic and one kinda magnifying. Or just buy it at HD.