Epoxy fibreglass on top of epoxy primer

I've got small hair cracks at fillet between the deck surface and
cabin side. It happened because there is a lot of putty with no
fiberglass layer on the top on it. It is painted with epoxy primer
(heavy coat) only. I like to add one or two layers of fiberglass using
epoxy. The deck, side cabin and the putty are polyester based.
My question is: should I sand the surface completely out of primer or I
can apply epoxy/fiberglass on the top of primer?
Thanks in advance
Adam

I've wondered about the same question when building cabinetry. It's be a
big time-saver to pre-prime sheets of plywood. I asked the Interlux tech
people and they were not willing/able to say that their 404/414 primer
(which is epoxy based) had any structural properties. Maybe the Gougeon
people might have an opinion. Let us know what you find out.


"seagoat" <adam DeleteThis @seagoatonline.com> wrote in message
news:1133370746.395473.261220@f14g2000cwb.googlegroups.com...
> I've got small hair cracks at fillet between the deck surface and
> cabin side. It happened because there is a lot of putty with no
> fiberglass layer on the top on it. It is painted with epoxy primer
> (heavy coat) only. I like to add one or two layers of fiberglass using
> epoxy. The deck, side cabin and the putty are polyester based.
> My question is: should I sand the surface completely out of primer or I
> can apply epoxy/fiberglass on the top of primer?
> Thanks in advance
> Adam
>