Last weekend I glued hull and deck together (Bear Mountain Endeavour). This weekend, I cut some ash rub-rails, and glued them on at the sheer, to hide some screw holes.

I wanted to glue on the rub-rail without using any fasteners (Moores method calls for more screws), so I hot-glued a series of guide blocks to the hull, to line it up properly, and hold it in position while the glue cured. That part worked fine, but after I removed the guideblocks, there was a milky-white discoloured patch underneath some of them.

This is not glue residue. Sanding has no effect on it, as if it is deep inside the glass/epoxy layer. In other spots, the hot-glue residue sanded off fine. This only happened under about half of the guideblocks. (If it was in a regular repeating pattern, I could at least pretend it was deliberate, but no such luck).

There is no glass weave visible. It is just a milky-white discoloration. The only thing I can think of is that this is heat damage. But I have never heard of this kind of a problem with using hot-glue? Anyone seen this before? Aside from peeling off a patch of glass in those spots, can anyone suggest a fix?

Thanks;
Ken