I think you guys have this backwards. ?It's the MEKP used to activate the catalyst in polyester and vinylester resins that reacts with polystyrene foams. ?My experience with Epoxy indicates it is relatively inert to polystyrenes, but it's easy enough to test with a polystyrene foam cup.
-Jeff Scott Los Alamos, NM > ----- Original Message ----- > From: Lawrence Bell > Sent: 02/27/14 10:24 AM > To: KRnet > Subject: Re: KR> Fiberglass rookie > > Hi Doran, > ?Been there done that. Epoxy resin will eat up polystyrene foam. As > John succinctly put it polyester resin won't and by the way doesn't gag > you with the smell. One other little thing I learned, polyester primer will > eat into it and produce gas bubbles, not good for the part. Use a 100% > acrylic primer after you have the surface smooth using polyester primer > mixed with micro to a peanut butter consistency you can mix a little > alcohol for spread ability . There is a lot to it, I have yet to get my > fiberglass parts to the finish I want. > Larry Bell
