Epoxy that won't yellow?

[Dick Strauss]

I'm looking for a medium to high viscosity epoxy that won't yellow over time. I sometimes use epoxy to fill small voids and know not to apply it too thick to avoid thermal runaway issues. I also use it as an adhesive for wood and stone. For example, I turned some carrara marble and had a chunk come out during the process. I repaired the piece with epoxy (no colorant) but the repair turned yellow over time with no direct exposure and minimal room exposure to the sun (in hindsight a white colorant may have been the best choice). I also color the epoxy from time to time and want the color to stay as mixed over time.

Any suggestions would be greatly appreciated. Is there any one product that can meet my needs?

[Larry Edgerton]

West system with 207 hardener.

[Dick Strauss]

Thanks Larry. I'll try that next time.

[Dick Strauss]

I don't have a pony in the race but I just found this youtube video about some third party testing that was done for anyone else interested...

https://www.youtube.com/watch?v=MzIxcIqCNh8

[Wayne Lomman]

Epoxy just yellows over time with exposure to UV. It doesn't detract from its performance however. As Dick's link shows, some yellow less than others but they all do it. It's the nature of it and you have to work around it's limitations and manage your expectations. Cheers

[Larry Edgerton]

I should add that when using an epoxy that will be exposed to sunlight I use a clear with a UV inhibitor as a top coat. Can be bought at any marine supply house.

[Michael Costa]

Since epoxy is being brought up, I've seen sawmill type people use an epoxy that's very dark gray in color to hold slabs together. I'm assuming it's because it's cheap. Does anyone know what this stuff is called?