Resin for glass fibre

[tigdlo]

I much prefer epoxy for everthing but wetting out chopped strand mat is a pain and it doesn't dissolve the binders so won't drape or conform to intricate shapes as easily.

 

[Kram]

The way I do it.. Place the mat on prepared part, apply excess resin on top. Wrap the mess with a polyethelene sheet/bag and massage it to ensure the epoxy/mat is fully wetted evenly.
When cured the PE bag will peel off easily without sticking, giving a smooth surface.

 

[Misterg]

I much prefer epoxy for everthing but wetting out chopped strand mat is a pain

You can get powder bonded CSM that will wet out with epoxy and can be laid up as normal. CFS, etc. can supply it.

The other potential ‘gottcha’ is that epoxy needs to be laid up wet on tacky. If you let the epoxy fully cure, it can develop an ‘amine blush’ on the surface that will reduce the adhesion of subsequent layers unless you remove it (using peel ply or giving it a scrub with Scotchbrite and soapy water).

 

[fixedfixer]

This is worth a read as regards applications Guide

 

[pedrobedro]

If it's for anything exposed to water then epoxy is more resistant, polyester is permeable and can crack up with frost and damp.

 

[Keith 66]

Its a plant pot, polyester will be fine, epoxy is overkill. Preparation is key, neither polyester nor epoxy will stick to dirty or greasy surfaces. Sand or grind the surface back with a coarse sanding disc on a grinder so clean material is exposed, wipe it over with acetone if you want to though it wont make a huge difference. Polyester will stick perfectly to such a prepared area.
Epoxy is good but as said you have to use the correctly sized glass or reinforcement otherwise it wont work as well.
Also Epoxy has virtually no UV resistance so if its going in the sun it must be painted over or it will fail.