If you like working with foam you can easily carve up a large block of foam with a carving knife but that isn’t very accurate and will make a huge mess. The cuts won’t be very smooth and it will take a long time to make something look good. The solution is a hot wire technique, a hot wire will cut through the foam like butter allowing the user to easily carve smooth sections of foam. Hao Kiet shows us his DIY solution in the video above where he is using the 5 volt output from a computer power supply. He connects the 5 volts to a guitar string which has a resistance of 2 ohms, this means that the power supply isn’t working very hard since the draw will only be around 2.5 amps. Hao uses a small plastic pipe as the main structure of the tool, with the power lines running through the pipe and connecting to two bolts which are then connected to the guitar string. It looks like he has used a bolt length that will prevent the bolt from heating up which could damage the pipe or the wire insulation running through the pipe.