Epoxy or polyester for chopped strand matting repair?

[chamy]

Hi guys, i needing to repair a 50cm long fibreglass crack.

I was intending to repair it from the back, with chopped strand matting.

The panel im applying it to is fibreglass.

Should I use polyester (normal) resin or epoxy resin?

Ive heard that matting usually contains a release agent that is designed to activate when mixed with the polyester resin, however I know from previous research that epoxy is generally stronger and more flexible (literally) than polyester.

 

[marc.w]

If you want to use epoxy resin for the repair then you need to use a powder bound CSM and not the ordinary emulsion bound CSM that is used with polyester resins. This is for the reason you mentioned, epoxy resin does not break down the binding agent very well.