�Is there a solution to this?��I'm experiencing a similar issue. The end grain is easily exposed by even light sanding. Should the fillet between the lapstrakes cover the end grain? Or do I need to add more layers of epoxy? Thanks for any help.

   Remember that you're looking at the hull upside down. Under most circumstances, those edges will be facing down so they'll be hard to see.  Maybe try turning it right side up and rolling/spreading the lightest of coats, tipping, repeating, and then the very lightest of hand sands w/ 220 grit. I wasn't nearly good enough a craftsman to do a varnished showpiece, so my canoe and the skerry were both painted inside and out.

And yes, the epoxy is supposed to completely fill the angle so there's a "meniscus" of epoxy in each corner.  I had to go back over mine w/ a syringe of slightly thickened epoxy to get a few dips filled on each strake.

Thank you. I am going to make the fillets wider to cover the end grain and then cover the general area with flag.

I agree with Mummichog: thicker fillet. 

I also think you may need to go a little easier with the sander, try not to get that roundover on the edges. I used 120 grit and a random orbital, just to lightly scuff it, not to remove material.

Once the first coat of epoxy goes on you should not normally see bare wood again. The purpose of sanding between coats of epoxy is purely to scuff it up to give a mechanical adhesion for the next coat. 

If the epoxy is so bumpy that you think it needs smoothing then maybe find a way to apply it more carefully. I always found it better to apply it as thin as possible. Worst case you have to do another coat. Put it on too thick, on the other hand, and you end up with drips, sags, wasted epoxy, sanding work, dust, and all that stuff. 

Disclaimer: I'm on my first build, only slightly ahead of you, about to apply paint :) So if anyone more experienced wants to jump in, please do!