Hi,

I recently skinned a plastic bonnet trim in CF using XCR resin.

Didn’t have any issues with applying the resin and then sanding the part to a flat finish. Once flat i applied a lacquer to add to the finish and provide protective layer as it was on the exterior of the car.

The part was on the car for a week and not noticed any issues but today was a slightly warmer day and i had also been out in the car for about 2 hours so the bonnet area had some heat soak from the engine.

When i parked up at home i noticed the finish was no longer flat but looked like a ripple effect, like the resin had sunk into the CF weave.

Took it off the car to try and sand it flat again but its clogging the sand paper almost like its still not cured?

When i sanded the part before lacquer i had left it over 24 hours at room temp and it sanded fine, no clogging.

Any advice is much appreciated... thanks.

What it sounds like is the resin has softened due to being relatively recently made and not fully cured prior to its first exposure to heat.  An oven postcure can help massively with this issue, especially for parts subject to a lot of sun and/or engine bay temperatures.  Epoxy's in general have quite a long tail end cure. 

As you say with a cheap lacquer it could be the same issue but with the lacquer - it needing more time to off gas all the solvents.

Warren Penalver
Easy Composites / Carbon Mods - Technical Support Assistant