Wednesday, March 22, 2023

On EVA

We were working on a demo unit at work and there was a gap that needed to be filled...lots of discussion later the engineers found a solution, but we brainstormed through a bunch of different materials and processes before we got there.

I mentioned EVA foam. Which I'd mean meaning to experiment with for a while but never got around to. Well, I broke down and ordered a pack of 6mm sheets off a certain company named after a long river.



Tried cutting. A snap knife worked best. X-acto for fine work but the blades dulled very quickly. Hot knife made nasty smoke and was hard to control.

Tried detail carving. A Dremel sanding disk did best. Coarse Dremel grinding wheel, a bit, but it wouldn't cut into the foam unless it "grabbed" and then it took too much. Neither wood rasp or other Dremel bits did anything useful.

Sanding was hit-or-miss. Bending with a heat gun was fine, and could do a very slight compound bend without buckling too badly. Contact cement worked absolutely great at bonding.

Did my usual paint test by quarters; painted half with plasti-dip, sprayed half of those with plasti-dip spray, and painted chrome paint over everything. The only place where it coated smoothly was when there was painted plasti-dip as underlayment; neither raw foam nor spray plasti-dip was a good prep.

Then bent and prodded and otherwise abused it to see if the paint adhered. Some creasing developed, but no cracking or flaking.

And I'd say at this point I know what EVA foam does and how to work it.

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