barrier coat issues

[oldfauser]

The boat was soda blasted last fall; the yard did 3 coats of barrier and VC-17 bottom paint. Lifted the boat off the cradle to place on jack stands to finish the barrier/bottom paint - the straps "peeled" the barrier/bottom paint off in chunks! Not good. Not enough drying time?

Question: will it finish hardening with bottom paint over it?

 

[Loren Beach]

I have to wonder what in heck they used as a "barrier" coat and if it was applied properly.
All of the ones I am familiar with are epoxy based and cure hard in 6+ hours.

Then there is the all-important Surface prep, even tho it consists of grinding, still has to be solvent-washed with the right chemical.

 

[oldfauser]

i feel the same... not sure what was done.. I was also surprised that the finish was not smoother - kinda bumpy - i watched them sand it last Saturday (it was smooth then) - and it was all done when i got there today. So they had to do all of it in two days...

i did find this - it can be done in two days.. http://www.yachtpaint.com/LiteratureCentre/interprotect-guide.pdf

they did do three coats - grey/white/grey the VC-17

 

[EGregerson]

barrier

its a shame to have a problem like that after all the work; what were the outside temps like at the time the 1st barrier coat was applied? was it done inside ; like a temp controlled environment? When i did mine, i put on a barrier primer coat 1st; it was pure epoxy and very temp sensitive. I hate to say it but i'd consider insisting stripping the hull and re doing it entirely.

 

[Frank Langer]

Art,

In the attached Interlux guide they differentiate between using Interprotect 2000 for preventive purposes or for blister repair/osmosis. The former only requires a coat or two, the latter requires 4 - 5 coats with the paint tacky when applying the next coat, and then a specified time before applying bottom paint. Was yours a blister repair or mainly a preventive step after removing your previous bottom paint?

We had a full blister repair job done on our boat last fall, and I watched the yard staff pretty carefully throughout the weeks long repair. They applied five coats of Interprotect 2000 after removing bottom paint and gelcoat and grinding/filling blisters. They applied the next coat when the last one was tacky (the thumb print test) and then I applied three coats of Micron CSC bottom paint. We moved the jack stands to ensure all areas of the hull were done. When the boat was lifted from the stands for launching, I noticed that where the last stands were, a small amount of the bottom paint came off, despite having followed all the recommended dry times. I'm fairly sure that none of the Interprotect 2000 was affected, but it's hard to be sure. So depending on how much of your paint peeled, some of that may be almost inevitable. Others may have more expert opinions....

Frank

 

[toddster]

As I understand it, there is a short window of time (thumbprint test) when you can apply paint over IP2000. If you wait too long, additional surface prep is required, or you will not get adequate adhesion.
If the IP2000 peeled way, it sounds as if it was applied over paint, not over fiberglass, or something else was wrong with the application.

 

[Cory B]

Little bumpy

Its been a long time (10 years?), but I recall that when we had Interprotect applied it was a little bumpy, not slick-smooth like gel coat, when completed. The bumpyness wasn't noticeable once it was painted. The yard ground off all of the bottom paint and some of the gel coat and "long boarded" the hull to make it fair again before applying.

I think we had 5-6 coats applied to get to our desired thickness, and the yard did 2 coats a day (?) so it would adhere well. They also painted the bottom very soon after the final coat.

Our's has held up fine, although we still get a few tiny blisters.

The barrier coat peeling sounds like a prep issue to me.

 

[oldfauser]

done for prevention

We don't have any blisters - it was done for the prevention of blisters - yard did three coats (grey/white/grey)

my guess is that not enough time elapsed before they picked the boat up with the travel lift. (temperatures have been cooler than normal) The yard is fixing the spots that peeled away when they finish the areas under the cradle pads... We decided to give it more time before launching...

we'll see...

thanks for all of the comments!