: I am preparing to epoxy the outside of my Coho hull, and would like to know
: if I should expect any benefit from sanding with a paper finer then the
: 120 grit called out for in the instructions. For most woodworking
: projects, I would end with 320 or 400 - why so course on the hull?

If you use a transparent epoxy/glass coating, so the wood is visible, there is a big advantage
to sanding to 220 grit. The wood will reflect more light and will have much greater depth
and luminosity.

Most of the epoxy companies, even the ones that build boats, don't use a transparent epoxy/glass
surface on many boats. And they don't have the wood finishing experience that furniture
makers do.

Any furniture maker knows why you sand wood to 320 or 400 grit. Because the wood will glow with
a even thin oil finish.

THE PROBLEM IS not in adhesion strength, but that the more you refine a surface the more every little
scratch you missed will stick out like a sore thumb. A bruise in the wood you didn't even see will pop
out when you finish or apply epoxy. Every ripple will be visually amplified.

You will have to really learn to fair a surface and sand to remove every scratch from the previous grit.

A lot more horsepower is involved the more you refine a surface and finish.

Take it up to next level!

Good luck!

All the best,
Rob