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Does anybody use West System epoxy 105/207? Answered

In my quest for an epoxy/resin that won't yellow when baked for half an hour at 230F, West System 105 resin with 207 clear hardener seems to be the one everybody thinks *might* work.  When I contacted the company, I was told that...

"The cured 105/207 should remain clear to 200F.
Above 200F to 300F you may see some discoloration.
300 - 400F you will see some discoloration."

So I'm in the maybe range.  But seeing as it will cost me around $100 to try it (they don't offer any type of sample size), I'm a bit nervous to buy.  Does anybody here use this epoxy who'd be willing to bake a cured blop in the oven and let me know if it yellows?  I'd really really appreciate it.



I have been using Mirror Coat from System Three. It's about the same price point as the West epoxy, but I prefer it because it is crystal clear and has better self-leveling properties. I have left some projects in my car in the Texas heat and they have not yellowed.


7 years ago

I might have some of that stuff. I'll have to check the numbers...

Thanks for checking. *crosses fingers*

I use USComposites 635 with the 556 Hardener. I've used it to build everything from canoes, to crossbow, to a research watertunnel. It's similar in characteristics to the West. Slow and thin.

I took a block I had glued up with some visible drips, tossed it in a 275 oven for 30 minutes, no discernable difference in color, it's also cheap, you can get a 24 oz kit for $16 and shipping.

1st bulk color

2nd pre cooking

3rd post cooking

crossbow 033.JPGcrossbow 057.JPGcrossbow 064.JPG

It looks like it has a slight yellow tint in all of your pictures. I'm trying to find a crystal clear epoxy for art projects. Although it sounds like awesome stuff for applications like the ones you mentioned.