I removed all the bottom paint, but...

[minaret]

Originally Posted by SVTatia

One further question:
It was easy to sand the rudder down to the fiberglass, looks like it was rebuilt and it did not have gelcoat.

I read somewhere that Interprotect 2000 should not be applied over bare fiberglass, and if so, would a coat of neat epoxy over the bare fiberglass be OK before the 2000?

Roll two coats of neat, apply 407/410 by chemical bond, tight sweep, to fill pinholes. Cure, sand fair, 2000, AF.

[SVTatia]

thanks much Minaret.
Thank you all who responded.

[Terra Nova]

What Min said.

It would be a huge mistake to skip applying a proper vapor barrier, now that the hull has dried so thoroughly.

[SVTatia]

Originally Posted by Terra Nova

What Min said.

It would be a huge mistake to skip applying a proper vapor barrier, now that the hull has dried so thoroughly.

Indeed. But... vapor?

[Terra Nova]

Yes, the epoxy coat is a vapor barrier to prevent water molecules from passing through your fiberglass hull. No?

[SVTatia]

Originally Posted by Terra Nova

Yes, the epoxy coat is a vapor barrier to prevent water molecules from passing through your fiberglass hull. No?

My apologies, I was never good in chemistry. I was just thinking of a kettle... never mind, I just haven't heard a barrier coat being named as such.

[capt jgw]

Fiberglass boats from the 1960s usually don't have blister problems. They changed the resin formulas during the oil crisis in the 1970s and that's when the problems started. This is one case where older is better. I'd just paint and go.

[Hudson Force]

Originally Posted by capt jgw

Fiberglass boats from the 1960s usually don't have blister problems. They changed the resin formulas during the oil crisis in the 1970s and that's when the problems started. This is one case where older is better. I'd just paint and go.

Good point! I noticed that many fiberglass boat manufacturers reduced the quality of their boats from 1973 to the 1974 year. That's when the cost of petroleum product resins increased by 500%. I remember that the 1974 Morgans had indoor/outdoor carpeting instead of the Teak & Holly and the rigging hardware was reduced,- smaller turnbuckles, etc. Production costs were difficult to manage.

[Hamish_ct]

I would try this before extensive sanding. Go to home depot and buy commercial grade tile cleaner. It will,state on the bottle,if you can use it for fiberglass.

Reduce it 50% and spray onto the blue coated,bottom. Let sit for a few minutes,than,wash it off with water and a sponge.

Worked on stain. For my boat...