Post #650670 by MadDogMike on Tue, Sep 4, 2012 8:59 AM

Will, I have carved some foam and experimented with some coatings, here's what I know in order of cost;

Monster mud is interesting. 1 part of latex paint and 3 or 4 parts premixed wallboard compound. It helps smooth out rough foam surfaces but would need a couple of coats of latex to seal it better for a more permanent application.

Latex paint is easy to work with, it does a fair job if you put several coats on. But as common as it is, it's not cheap - about $30/gallon. You can buy mismatched paint for cheaper as your base coats and then put your color coat over that. You can even use spray paint after several coats of latex if you don't get carried away. Latex dries fairly hard after a couple of months.

I tried water based polyurethane on a project a month ago and was not impressed. I put several coats on and when I sprayed it with spray paint, it bubbled.

I used some Steve's Coating for Foam ($55/gal). It's a one part cross linking polymer liquid that is brushed on. It took several coats to get a decent thickness but it seemed to have worked OK

The latest one I tried was StyroSpray 1000 ($32/half gallon) and it's the best I have found so far. It's a 2 part (epoxy?) product, has a pot life of about an hour and make a hard shell. It's not cheap but it's only $30 more per gallon than latex paint and much better. Plus it cures to full strength in a few hours instead of a few months. It can be sanded, machined etc.

EDIT - there's one more I haven't tried called Rosco Foam Coat at $70/gal.

"Some days its not even worth chewing through the restraints"

[ Edited by: MadDogMike 2012-09-04 09:01 ]