Asked on Nov 18, 2018
How can I clean my epoxy cabinet tops that turned yellow?
by Peggy Black
I did my cabinet tops in expoxy about 2 months ago, now they are turn? They have turned yellow in some areas, what can I do?
Suggested Project Book
Is the yellowing under something? Sometimes that happens because of lack of exposure to light. Also the opposite can happen if a spot has direct light on it. It's weird, had both happen. That's why I don't recommend it. Nothing to do but strip off and do it again or live with it.
You have likely applied a polyester resin that used peroxide as a hardener. This stuff is reactive to UV sources and does change color to a transparent yellow then eventually to brown especially if exposed to heat.
Note that polyester resin is a type of epoxy resin… it is just the cheapest version. The best and most expensive non-yellowing epoxy will be a urethane (NOT polyurethane) that often cures by exposure to the humidity in the air.
You can coat the epoxy resin with a polyurethane that has “UV protection” as one way to prevent yellowing after the resin has completely cured (that UV-protection characteristic should be indicated on the label).
Also check this out:
https://www.aeromarineproducts.com/polyester-resin-vs-epoxy-resin/