Primer or Epoxy barrier coat?

[Boatyarddog]

Originally Posted by Terra Nova

Barrier coats are applied over the gelcoat.

When addressing wet hull issues, you don't leave gelcoat on, as the glass underneath cannot dry effectively.
It is first removed and the Bare fiberglass is allowed to dry out to less than 10% moisture, this can take awhile depending on working conditions.
Then a barrier coat of some type is applied to seal off the glass.



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[Terra Nova]

Originally Posted by Boatyarddog

When addressing wet hull issues, you don't leave gelcoat on...

We are not addressing wet hull issues.

Where are you getting your info, Google?

[Boatyarddog]

Originally Posted by Terra Nova

Barrier coats are applied over the gelcoat.

You may benefit from this prep sheet for epoxy barrier coat from Interlux.
http://www.yachtpaint.com/Literature...tb-usa-eng.pdf


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[Boatyarddog]

Originally Posted by Terra Nova

We are not addressing wet hull issues.



Where are you getting your info, Google?

The post is about barrier coats, Interlux inter-protect is a barrier coat, applied over sanded gelcoat or bare fiberglass, to seal out moisture, that's it.
Don't really understand your continued rant, it was mentioned that to seal out moisture, a barrier coat may have been used, they aren't sure, the gelcoat could be removed or not.
I've applied barrier coating many times, zero failures. And I'm certain your not the only one that has used it.
You can lower your hackles friend.


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[Terra Nova]

Your misinformation was that you needed to remove the gelcoat before applying a barrier coat--simply not true. You just sand the gelcoat, not remove it.

[Mackaroni]

Thanks for all the information. I have two coats of grey that I guess is a barrier coat of some sort....not sure what kind. Underneath it is gelcoat. I have to be real careful though not to chew through the gelcoat. Even though I am using a finishing sander, it can go through the grey stuff and get to the gel coat quickly. I accidentally went through the gelcoat in one small area (3mm) or so when I was using 60 grit to get through the grey. I will have to put some fairing compound over that before I epoxy barrier coat it.

[mariner36bob]

Mackaroni that grey paint is your epoxy layer. Should sand harder than the ablative. Are you just removing the barrier coat where the moisture meter pinged on the keel or all over? Is the epoxy coat failing? Just wondering if it's intact. If it were, you could save time and $ by giving it a good light sanding and laying ablative right over it.


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[Mackaroni]

I've taken a some of the barrier coat off unfortunately. Not everywhere, but enough to where I think I am going to have to reapply the barrier coat. I have exposed the gelcoat in several places and might as well just strip the rest off and start from scratch.

My one thought while I have been doing all this is that I am glad I don't have a 50 foot boat. I can't imagine doing this much sanding on a bigger boat.

[Terra Nova]

Originally Posted by Mackaroni

...I have exposed the gelcoat in several places and might as well just strip the rest off and start from scratch...

What are you thinking!?

You want as thick a barrier as practical. Unless there is an adhesion or compatibility problem, there is no need to keep sanding and sanding.

[mariner36bob]

^ what he said. Yeah buddy I'd stop. Fair where you've gone too deep and start painting.

However, now is the time to remove all from that spot which pinged the moisture meter. You may find a wet spot or just a fiberglass repair that had been made, etc.


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