DIY Hot Wire Foam Cutter

**Super** · **Super** 01-18-2019, 05:24 PM Track Engineer

If you have ever gone through the mess of cutting white foam board you know what this is about. I have tried everything and the best (least mess) I could come up with is using a hack saw blade or a serrated kitchen knife. But even then the cut edges would still crumble pieces away. I always wanted a Hot Wire Foam cutter that would cut the foam easily and seal the edges at the same time but could not justify spending the money for the few times I would use it each year. Now, with the help of this amazing DIY Video I can make one myself for penny's. I have ordered the wire and already have the rest of the materials on hand to make one.

Off The Rails · Off The Rails 01-19-2019, 05:14 AM Posting Freak

That’s pretty ingenious. I’ve seen other DIY foam cutters but many of them were a bit more complex than I thought I would need. I’ve also considered buying one from Foam Factory or another hobby manufacturer but I always ended up spending the money on other things. This looks totally “do-able” and fairly inexpensive.

**Super** · **Super** 01-19-2019, 08:32 PM Track Engineer

I will Post back on my experience once I build it. My initial question is how long the battery would last connected across the positive and negative like that. I am thinking that a mini momentary button switch might help. One that needs to be held down to make connection and when released turn off.

chrisjo · chrisjo 01-20-2019, 08:53 PM Investigations Dept.

In my experience you need to have a quick and easy way to adjust the tension in the wire, which changes markedly when you apply the current. With this design I suppose you can turn one of the bolts, but I didn't see mention of that on the video.

**Super** · **Super** 01-20-2019, 09:03 PM Track Engineer

Do you have a retail one C-Jo? If so, how do they adjust the wire tension? Do you think that tension is much more affected by what gauge wire is used?

chrisjo · chrisjo 01-20-2019, 09:28 PM Investigations Dept.

No, I have a (rather over-engineered) home-made one:

**Super** · **Super** 01-20-2019, 09:59 PM Track Engineer

Thats a good looking DIY item C-Jo. How do you add tension in that one?

chrisjo · chrisjo 01-20-2019, 10:05 PM Investigations Dept.

You turn the screw in the close-up picture, between your forefinger and thumb. That acts on the hinge.

**Super** · **Super** 01-20-2019, 10:09 PM Track Engineer

I see...brilliant. That wire looks thin, do you know what gauge it is?

chrisjo · chrisjo 01-21-2019, 02:18 PM Investigations Dept.

No, I'm afraid I don't. I made this maybe 20 years ago, and obtained a stock of wire then, but the details are lost in the mists of time. However my trusty micrometer tells me it's about 0.22mm diameter, which would make it closest to AWG31. It works with a 12VDC PSU.