I have done this before but decided to share it this time; I'm always amazed how everybody thinks that polyester takes UV and epoxy
not. It is not that black and white. My polyester gelcoat
is completely shot after 19 years tropical sun on it, and I have the Rolls Royce of gel coats so often it'll be worse.
We never put polyester under the sun, we put polyester gelcoat
under the sun. That stuff has more than just resin and hardener.
So if we want epoxy
we use MarineTex. The small packges are a b^tch to work with as the paste is very tough, the hardener liquid, and the mix still too tough to use a syringe. I'll try to thin that with aceton next time, but sometimes I just make something up myself. There is no data on how well it weathers, it probably won't do well... but I have some spots where it has been for years and it's still good.
Okay, here's the recipe:
- West System 105 resin
- West System 206 slow hardener (this should be the UV resistant hardener that I don't have!!)
- A little cabosil / colloidal silica to make it like a thin ketchup
- A squirt of West System white pigment
First mix resin with hardener, then add pigment (max 5%), then add cabosil. I use a syringe to apply it on small cracks that I firsts grind out. Note: these are mostly under the hatch
frames that I am rebedding to with UV protection. But there are lengths that come out from under the flange and get UV. I will paint
that area one of these years and just hope it lasts until then.
Here is a picture from a piece that cured inside a syringe and popped out after that (West System syringes don't adhere to thin epoxy)