Fast heat Heating Panels kit build. The kits are great. Everything you need is in the box (except tools) and you don't have to know how many feet of wire at what wrap gives you the right resistance to make each one 1200 watts. And then how far to stretch it to make it fit and still keep the edges warm so there are no hot spots. All those calculations are worked out for you. That said they are still kits and have to be very carefully assembled so as not to break the ceramic fiber board or kink the wire. There are many hours in this project and this step is one that takes longer than it looks.
I note about the heating panels. This is the heart of the machine. If this doesn't work well you do not get good performance out of you vacuum former. The TK560 forum goes on and on about this topic. It all comes down to this. A vacuum form machine is an oven. A big oven. In fact by the time I have both zones of mine working it is twice as much power (in amps and watts) as a kitchen oven. A very good source said (see link below) that you need to heat the plastic from room temperature to forming temperature (about 350-400 F) in about one minute to keep the plastic plyable. Heat too slow and you change the plastic elasticity. This is like baking 15 minute rolls in one minute. It takes a lot of heat. This my second try to build a machine. The first I abandoned for lack of heating power. 110v was not enough. The kits are not cheap. Trust me, I know, but heating is king in this game and Doug has it worked out. For more, read down around page 16 of this document from one of the commercial heating element suppliers which talks about Estimating Power Requirements. It works out to just under 11 watt/in2. That's watts per square inch. So, if you have a 2' x 2' machine that's 24 x 24 x 11 or 6336 watts a minute you need.
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