Hot foam cutter newbies

[edwisch]

So two friends and I are messing around with hot wire cutting and will then start messing with resin infusion, just to give it all a try.

Today was the maiden voyage of the hot wire cutter and it worked reasonably well on our first three cuts. However, often we would get spanwise grooves, usually on the flat portion of the airfoil-ish section we were experimenting with. That's probably a common phenomenon, but we don't know what causes it, nor have I found and videos that show how to make airplane-size foam sections. I've found lotsa decorative things with vertical wire cutters, and some model airplane stuff, but nothing to help us come up to speed.

IIRC, we were using nicrome wire at 24 V, but for longer pieces will probably go to 48 V and let the dimmer reduce the voltage.

Thanks for comments, suggestions, and links!

[Kent Ashton]

Spanwise grooves— sounds like a jazz ensemble.    The templates need to be very smooth.   File or sand the edges smooth.   Scrap Formica makes pretty good templates.    If the wire stutters or hangs on the edges, it burns a little deeper into the foam.   The wire will usually be hot initially, then cool off after an inch or two of cut.    Also keep the rate of movement consistent  after the wire temp stabilizes.    If one person hesitates, it will burn a groove.

Edited December 6, 2020 by Kent Ashton

[charlesreily]

The type and quality of foam can impact the cutting process. Some foams may have uneven densities or may not be well-suited for hot wire cutting. Experiment with different foam types to find the one that works best for your needs.