: I am trying to complete one of Nick's Microbootlegger kayaks, my
: first strip build. My plan is to fair the
: interior by filling gaps with epoxy thickened with phenolic
: microballoons, level everything adequately,

: My question: leaving cosmetic concerns aside, just how smooth and
: flawless does the interior surface need to be in order to
: properly apply the fiberglass?
: result?

Your plan sounds just like the right thing to do if a little more than you need. I do not fill the inside of my boats and I only sand with 60 grit to level and smooth the surface. You can sand with finer grit around the cockpit and hatches to increase the bright finish were it can be seen. The most important part to me is getting a nice smooth surface to allow the glass to lay flat against the wood and not allow for any epoxy to pool or air bubbles to collect. Adding micro-balloons sounds like a great idea to fill gaps and keep the epoxy weight down.

I suggest you look at this website to read up on glassing methods to get a perfect wet out. Lots of good tips here. If you have taken your hull off the forms then you must put it back on before glassing. Yes you MUST put it back on before you glass to maintain the shape of the boat as the epoxy cures.

Robert, Visionary