Hi Dean, My guess is that the darker area is where the epoxy saturated the wood a little more, hence darkening it more. The lighter blotches are probably places where the epoxy didn't penetrate as well.

To eliminate the possibility of splotches like these, you'd had to have sanded the entire hull (before glassing) with the same grit of sandpaper, and coat the entire thing in a single coat.

Sanding the hull with different grits would have caused the epoxy to saturate the wood at different rates. Coarse, rough spots absorb a lot, spots sanded with 200 grit and above hardly absorb any.

If it was a warmer day when you glassed the butt joints, the epoxy may have saturated more than if it were colder (was it a bit colder when you glassed the hull?)

My only other guess as to the light spots--look closely--are they tiny bubbles?

There's not much you can do at this stage, other than varnish your boat and go out and enjoy it. I promise, the average Joe will never notice the color variations, and even your fellow boatbuilders won't notice unless you point it out to us!

Sorry it doesn't leave you with many options, but look on the bright side--the boat's almost complete!

Shawn

> I have just completed (less varnish) a Pygmy Arctic Tern, which employs
> butt joints that are held together with fiberglass tape and epoxy on both
> sides of the panels. When the original gluing-to-length process is done,
> epoxy covers about 2 inches of either side of the joint. The problem is
> that after having built up the boat with a full covering of fiberglass and
> epoxy, there is a slight, but visibly dark swath about 4" at the butt
> joints. Is this just due to more epoxy in these areas or did I screw
> something up? Also in the butt joint areas I have a few irregular blotches
> that are a lighter color. Any clues on what this is?

> Dean