Check with your marina but that brown sruff might be easily and painlessly removed with one of the citric acid or like, products

 

Does it have blisters now?

 

Obviously a barrier coat is not a bad idea... it costs, takes time and adds some weight. But it will be a barrier that you don't presently have.

My boat had no blisters, but I "went to town" about 10 years ago... soda blasted... I was told 1,000# of old paint came off (25 years worth) YIKES... I did the fairing and the barrier coat... and the bottom paint.

 

I went through the exact same process as SanderO five years ago: soda blasting, light sanding to remove residual blush, fairing of the enviable pits, another light sanding, followed by 4 coats of Interprotect 2000 and then 3 coats of Hydrocoat. Like SanderO, there were no known issues (nor did we find any) with the gelcoat. Nonetheless, I was able to verify the sound condition of the hull and put the barrier coats on as a primer for the antifouling paint (and to feel good that the hull had a little more protection). This is not the first boat that I barrier coated and my experience is that the antifouling paint stays attached for many years with no flaking.

P.S. My 1990 hull had vinylester gelcoat, which was supposed to prevent osmotic blistering. From what I can tell, it certainly worked!

 

I have no blisters on the hull, but there is a small blister on the keel.

Is it possible that the brown coating on the hull that's flaking is an original barrier coat or just 35 years of VC17?

Rob

 

Correct me if I'm wrong, but isn't VC-17 supposed to be applied to a clean, dry, bare hull?

If so, don't you want to get all the old stuff off ? Certainly, anything flaking has to come off.

 

Typically I give the hull a quick sand and apply the VC-17. The issue is now that there are a number of spots where any bottom coating has completely flaked off. In the past i may have locally sanded those areas and just re-painted with VC17. Now I'm wondering if what is flaking off is VC17 and barrier coat.
If thats the case just painting over with VC17 is not going to cut it and I may need to completely strip the hull.

 

If that's the case, I had a similar problem with my lead keel several year ago. The hull was good, but the paint kept flaking off the keel each year, taking barrier coat with it. When I stripped the flaking paint, it exposed large sections of bare lead. However, much of the barrier coat still remained though, I decided to strip that too, much harder to come off than the paint. In fact, there was an area about an inch down from the keel joint and all around that was so difficult to remove, I just decided to leave it. I got everything else down to lead and applied 8 coats of barrier. Haven't seen peeling bottom paint there in years now.

You might want to sand all the old paint off, and see what you have under it. If there's intact barrier coat, it won't come off with normal sanding. Then you can decide what condition most of the barrier, if there, is in.

 

If your '85 hull hasn't blistered yet, it's probably not absolutely necessary. I would think that era would be on the bubble of the change to less osmosis prone glass hulls. I'd do it anyway, if you can't determine is was already done, but probably only a coat or two to fully cover, rather than the 2-4 coats recommended for blister prevention. I think it's a better prime coat for the anti-foulant.

Personally, I'm just a fan of knowing the bottom was done right and knowing every product that is on it. Chasing flaking, build up, adhesion issues, etc, is both frustrating and costly.

VC17 is probably the easiest bottom coat to remove. Solvent will do the job. I've not done it, but I imagine it's messy. Acetone, MEK, even Interlux thinner. However, I'm just imagining it running down one's arm, while reaching above one's head. Yuk.

A vacuum sander is as close to wiping it off as you can get and I have done that. Still a lousy job, but much faster than most other coatings.

Start bare, put all the work into proper preparation and build the coatings properly. Saves time and money in the long run.

 

I have a 1985 S2 27 that on the Great Lakes

Robert

Robert,

I am looking to buy an S2 27. I'm in Michigan. Any chance yours is for sale? If so please contact me at email: dhoffman888 @ gmail . com

Thanks!

 

There is more to it than just sealing the hull. There is bottom paint primer aspect to consider.