My Hotwire Table

General Discussion
21
Quote:

Step 6: hook up power with alligator clips (roach clips) and DON’T TOUCH THE VOLTAGE REGULATOR YET!!!

ok, now “tug” just a little to make sure you’re on your crow’s feet, and down the center. The guides are coated in melamine that doesn’t burn, so pick a side on the handle-side guide and follow that side. Now:

Step 7: Hit the power and pull!! We’re using about 9’ of 25 ga. nichrome, takes 55 volts to go fast enough (and haven’t popped a wire yet) so DON’T TOUCH, 55 volts would def. light you up. The key is to follow the guide, and keep pretty good pressure. If you’ve attached it well enough on the handle and the other end, you can apply some pretty good pressure, now pull. Splitting generally takes us about a minute, slower or with a “loose” wire, it just drifts in the foam, no bueno…

Drew,

If you don’t want to spend the money on Nichrome wire; I use stainless steel liter wire that works well. Some things I have read about hotwire cutting even recommend against using Nichrome. I think it had something to do with the higher temperatures that it can reach damaging the foam. FWIW - Anyone else ever heard of this?

22

I found this online… not sure why he says not to use nichrome. Greg Loehr recommends it. I’m using stainless and it seems OK.

The 10 most common errors in foam core cutting are.

  1. Too much heat on wire.
  2. Not enough heat on wire.
  3. Using the wrong type of wire. NEVER USE NICROME WIRE.
  4. Not enough tension on wire.
  5. Too much tension on wire.
  6. Electrical short of the wire support arms on the cutting bow,
  7. Wrong template material.
  8. Moisture in the foam. (stored outside in rain)
  9. Never use a little wheel to support the bow during a cut.
  10. Wrong angle of the pull wire to the template.

If you avoid these problems your foam parts will be great. Your rejects will be low if at all. And you will enjoy the whole thing more.

http://www.public.iastate.edu/~orman/air/cutter/hotwire.html

23

Nate,

I tried many different wires, including piano wire, copper, stainless, the two types from ACP, just found nichrome works best. Might be the foam I’m using too. But we’ve been doing quite a few here and the nichrome is by far my favorite. As for cost, check Ebay. I’m getting it pretty cheap. I’ve also heard of a wire from Insulfoam in Ormond that a good friend recommended. He claims the temp range to be much higher, example if you can cut with the nichrome at 25 volts, and 27 is too hot, and 23 is too cold, this stuff has a MUCH larger range. Might be beneficial. I’m not sure why they tell you to stay away from nichrome? I’m sure there’s as many wires to use as methods to cut, so experiment and let us know what works for you.