What type of material is flexible but not too much, water proof, and can tolerate 80°C temperatures? [closed]

Question

The idea is to build an electric pad with an non-coated heating wire (~1.3 Ohm/metter): the pad must be flexible under the bed sheet (like this one) but not too much (to prevent it being crumpled which would damage the heating wire and might create shortcuts that could dangerously increase the heat).

This tuto recommends using a PVC+fiberglass mosquito net, which is a good idea since it is flexible but can't be crumpled and on the same time does support relatively high temperature. But he used a coated wire (these wires are, for mysterious reason, not sold anymore). So it might be dangerous with on non-coated wired since mosquito net are not really waterproof and sweat/moisture might create interesting shortcuts...

Any idea of material(s)/fabric that would meet those criteria:

• flexible but not too much.
• non conductive (for electricity)
• tolerate 80 or 100°C (~180F) heat
• doesn't emit toxic particle in contact with heat. (It would be use under bed sheet...)
• relatively cheap

ps: I was thinking to use the mosquito net buy insulating those wire using heat-schrink tubing but I'm not sure they could stand the 80°C heat from the wire, and about toxic emissions.

ps2: notice that it's not a safety related question, but a technical one (I'm looking for specific material).

Answer 1

The project you linked is for a small heating pad on a chair, and uses insulated wire to prevent electrical shorts. This is relatively safe (though not as safe as just buying one) mostly because the person using it is awake and alert - if it starts arcing or overheating they will notice.

Building your own to heat the whole bed is a much riskier proposition. You (and potentially loved ones) will be asleep and may not notice such problems quickly enough. Using uninsulated wires just makes it that much more dangerous. If you start a fire, you will probably find your insurance won't pay out after the fire inspector determines the cause to be your jerry rigged heating blanket.

I am all for DIY, especially building my own electronics, but sometimes it is best to leave it to companies that can afford to do a lot of safety testing.

Heating blankets are easily available at many stores, and probably won't cost much more than the parts and material you need to build your own. They are tested for safety and usually include cutoffs to prevent overheating and shut off if more than the expected current is drawn (if a wire shorts inside).

The linked project says it is more durable than a heated blanket because it doesnt have to be cleaned. But I have had one for years, washed regularly, with no issues. If that is a big concern put it under a plastic sheet so it never gets dirty.

So just buy one, and use your heating wire for more interesting projects, like foam sculpting or building an awesome fog machine.

Answer 2

Probably ABS plastic fits the bill. But, as others have noted, this sounds like a terrible and dangerous idea. Don't set yourself on fire.