I recently made a structural repair and using west system epoxy and slow hardner. I think I read somewhere that you cannot apply white gelcoat over this system. Now what? Any ideas appreciated here.
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Grind it off and re-do it.
John: I just had the top of my water tank glassed into the liner. That is exactly what they needed to do. Removed the gelcoat from the liner and the lid. They they applied Fiberglass and resin. Then this area was re-gelcoated to make it look finished.
John: I just had the top of my water tank glassed into the liner. That is exactly what they needed to do. Removed the gelcoat from the liner and the lid. They they applied Fiberglass and resin. Then this area was re-gelcoated to make it look finished.
Polyester won't bond to epoxy.
At least that is what everybody says, but they are only partially correct. Polyester resins (gelcoat) won't chemically bond to epoxy, but they can make a physical bond. Clean the area real well with vinegar and acetone to get rid of any amine blush and other contaminants. Then rough it up real good with some coarse sandpaper - I'd use 60-80 grit. Clean it again and apply your gelcoat. Though the gelcoat won't stick as well as if you had done the repair in polyester, it should do the job. Besides, what do you have to lose by trying?
At least that is what everybody says, but they are only partially correct. Polyester resins (gelcoat) won't chemically bond to epoxy, but they can make a physical bond. Clean the area real well with vinegar and acetone to get rid of any amine blush and other contaminants. Then rough it up real good with some coarse sandpaper - I'd use 60-80 grit. Clean it again and apply your gelcoat. Though the gelcoat won't stick as well as if you had done the repair in polyester, it should do the job. Besides, what do you have to lose by trying?
gelcoat and epoxy
West Systems adds another caution: they maintain that gelcoat will adhere to epoxy IF... the epoxy is cured correctly. That is to say, the right ratio of hardener to resin is used and the catalyzing process is complete.
West Systems adds another caution: they maintain that gelcoat will adhere to epoxy IF... the epoxy is cured correctly. That is to say, the right ratio of hardener to resin is used and the catalyzing process is complete.
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