On Wed, 24 Mar 2010 19:54:19 -0700 (PDT), Frogwatch
wrote:

I had forgotten about Marine-Tex, great stuff and they are right, it
does not run. Basically it is epoxy with a thickener.
However, when making repairs, I like to use thin epoxy first to have
it soak into the surrounding area and then while it is still soft I
fill in with thicker stuff. That way it is bonded all the way into
the surrounding area instead of relying on a mechanical bond to the
surface. That's my theory at least.

It's a good strategy but it is important to let the thin epoxy start
to cure before overcoating with the thickened top layer. Otherwise
the thin epoxy will start to sag from the weight of the top coat and
take everything down with it.