How often do you need to repaint the barrier coat

[saurav16]

Hello,

I was wondering how often do you need to repaint your barrier coat, how do you know when you need to paint your barrier coat? Also I know to do this you have to sand off the antifouling paint but do you have to sand off the original barrier coat as well? Thanks!

[Sailormon6]

I've barrier coated 2 boats and have never needed to re-do the barrier coat. I don't think that, as a practical matter, you ever need to re-do it again, unless it is damaged. In that case, I'd just sand it smooth where it's damaged and re-coat that area. It's possible that it breaks down over a very long period of time, but I have no idea how long that might be. I believe barrier paints came into widespread use in the late 1980s, and there might not be a good record yet of exactly how long they last. If you want to do a bottom job on your boat, stop sanding when you get through the antifouling, so that you don't remove any of the barrier coat.

[bubb2]

Great thread! I don't know the answer myself. What I do know, is 9 years ago we purchased new a Beneteau witch has a iron keel. I applied 2 coats of Interprotect 2000 on the keel at that time. 2006 at haul out had 2 or 3 spots 2 to 3 inches round where you see rust weeping out under the bottom paint. I sanded until I had bright metal and recoated the Interprotect and bottomed painted. At the 2007 haul out, no rust was found. I don't know if the barrier coat is giving up the ghost or if I had just week spots. Time will tell.

[camaraderie]

Barrier coats don't need to be redone unless something breaches the barrier.

[sailingdog]

You shouldn't have to re-paint a barrier coat unless you've accidentally (or intentionally) sanded through it, or otherwise damaged it. That is one reason it is a good idea to use a barrier coat that is different in color from the hull.. so you can tell when you've screwed it up. Generally, two-coats of barrier coating isn't sufficient in thickness to really do the job right.

[halekai36]

It's kind of like asking how often should I re-gelcoat? Barrier coat is NOT a paint and is basically an epoxy resin. It should never need another coat as long as you built up to the proper thickness when you applied it..

Barrier coat is not a maintenance item unless you breach the surface of it then you simply touch up that area..

[BarryL]

Hello,

My boat was barrier coated some time ago.

Unfortunately, the hull must not have been properly prepared before the barrier coat was applied. The barrier coat developed what looked like cracks, and would flake off of the hull. Any antifouling paint would also fall off the hull.

It was very ugly. This past winter I had all the old paint stripped off. A good deal of the old barrier coat came off as well. The barrier coat that didn't is really on the hull.

Today I applied the first coat of new barrier coat. I was VERY careful to prepare the hull.

I don't ever want to do this again!

Pic of the old hull.

Barry

[saurav16]

Thanks all for your responses. I guess unless I get a blister or something or breach the coat I do not need to repaint it.