Cutting Under Water

[Joseph Shawa]

So I took a baking pan and filled it with about 3mm of water.

Test fire 100% and hold > boils water instantly and crackles.

1mm thick copolyester. (PETG)

Cuts great under water believe it or not. So long as the water isn't more than a a couple of mm or so over it AND there is less smoke.

What I did learn though is that the "Flashback" that was supposedly causing the discoloration of my material was in fact still occurring even under water. It seems that the material is actually blackening internally and not removable.

So I did a bunch of speed/power trials and found that copolyester actually cuts MUCH cleaner at slow speed. Normally I have been cutting it a 80mm/sec and 100% power.

When I got down to below 20/20 there was only a haze near the cuts and it was almost completely removable with alcohol.

I'm now going to try cutting at lower Hz to see what that will do. Quick edit. No difference

[Joe Pelonio]

Inyteresting idea! I never tried that, but for nice clean cuts on nastier materials, I put transfer tape on both sides and mist the top with water before cutting. My biggest regular job is 2,000 pieces of 1/16" ABS and it cuts without any discoloration.

[Kev Williams]

What transfer tape do you use? The stuff I use, once it gets wet it loses adhesion and falls off-- it actually works great for AFTER cutting, rather than all the peeling I just put all the cut pieces in a sink of water. 10 minutes later all the paper is off :)

[Rich Harman]

What I did learn though is that the "Flashback" that was supposedly causing the discoloration of my material was in fact still occurring even under water. It seems that the material is actually blackening internally and not removable.
If the part you are cutting is against the baking pan, I think you still with have "flashback".