You can go quite coarse, eg 240 grit, as long as you work your way back up the grits if you want to lacquer or polish it.  The XCR has a high level of UV resistance but is not 100% UV stable so in very sunny climates with high UV exposure, you may want to consider a UV stable lacquer.

Also remember you might want to do a post cure if said environment is warm too.  On a hot sunny day, the resin can soften if you don't do a post cure.

Warren Penalver
Easy Composites / Carbon Mods - Technical Support Assistant

Whilst trying to find the answer to my own question. I have come across a statement that generally I need to do a coat of lacquer over the top to ensure that I the parts do not discolour yellow over time. 

Is this the case with XCR resin? Will I need to lacquer it to keep it looking new?

Hi, I am skinning an item in carbon fibre.

I have laid the carbon and sealed it with 3 layers of resin which is fully cured. I always use 400grot paper here to completely flat out the surface before one final thin  coat of resin.

I have been unable to sand out some of the low spots with 400grit. My question is, how low can I go in terms of sandpaper grit here? Will a coat of resin hide the scratch marks of a 200grit or maybe even a 120grit paper?

Thanks in advance for any help you can give.