Hotwire Cutting Two Pound EPS

How many of you are hotwire cutting two pound EPS. Never tried hotwire cutting one pound (not making a compsand) but I think two pound might be very different to cut than one. Any tips for the denser stuff to speed up turn around time. I’m on stainless leader wire with a 10amp 13.8v power supply. Much quicker than nichrome but still no speed demon.

I can’t really remember how it was like to cut 1 lbs EPS, but I’m pretty sure it was faster… It’s no big deal cutting 2lbs, just make sure the wire has good tension, use nice and even templates and take your time. An adjustable power source like a variac is helpful too.

regards,

Håvard

I watched a 2.5 lb. blank get cut on a machine. The wire moved slow enough that the foam never really touched the wire. The heat from the wire melted it before it touched. No residue. That was interesting.

I use inconel wire. It’s what is use by large EPS cutting houses. 3 pound EPS no Problem. My friend can cut 8 boards every three minutes on a hotwire cnc using inconel wire with a spring for tension. That’s with outlines and cut down the center for adding your stringer.

I bought a 100 ft roll of Iconel two and a half years ago and I’ll get two or three more years out of it.

Wow that’s fast! Doesn’t it cause alot of smoke at that heat/speed? I’ve tried to increase the heat & speed, but I always get smoke. However I think the smoke is mainly from residue on the part of the wire that is not in contact with the foam. That part of the wire is most likely considerably warmer than the wire inside the foam. Secondly if the wire is not in constant motion it starts to burn into the wood templates…

regards,

Håvard

Quote:

Wow that’s fast! Doesn’t it cause alot of smoke at that heat/speed? I’ve tried to increase the heat & speed, but I always get smoke. However I think the smoke is mainly from residue on the part of the wire that is not in contact with the foam. That part of the wire is most likely considerably warmer than the wire inside the foam. Secondly if the wire is not in constant motion it starts to burn into the wood templates…

regards,

Håvard

Havard, you’re right the smoke’s coming off the sides, and it’s nasty! We run a fan lengthwise to the block, this helps cool off the wire outside of the foam, hopefully keeping the wire hotter where it’s cutting the foam. Also, gets rid of the fumes so we’re not getting fumigated. As for leaving the wire sitting too long, a couple of my rocker templates are testimony to what you’re talking about, those notches are just sitting there waiting for the next blank and the wire to get caught during the pass leaving a weird spot in the blank!

Deanbo, we’ve been using 150 lb test stainless leader using a variac set at something like 18 amps on 2 lb EPS, kind of slow, but not any worse than the 1 lb block I cut before that, takes maybe 2-3 minutes per side (seems longer than that).

Deanbo,

Good 2# EPS at a heat/speed ratio that will cut clean and not drag usually runs at 12" in just under a minute. That was on CNC machine where we could fine tune the heat and speed down to the gnats ass. If we saw smoke (other than an puff here and there) we were checking to see what was wrong. The foam should just be “evaporating” just in front of the wire in a clean cutting rig.

Steve