To Blister repair or not??

[Mich222]

a

 

[Shoaldrafter]

Mick 222 & Blisters

Mick:

In the southeast, blister repair is routine maintenance. If you plan on keeping the boat or eventually selling it, I recommend yearly repair.

However, any blister repair should be done well and not half arse.

Blister repair ususally begins in the fall. The hull is pressure washed and blisters noted. If small number then they can be repaired individually.

If large number then hull should be stripped of any bottom paints and all blisters opened and then hull washed again. If the number of blisters is large then sand blasting is the easiest way to open all blisters for drying.

Then hull should be dried for several months and occassionally rewashed to keep removing acid residue from blisters. Acetone wash facilitates bad residue removal.

When hull is fully dried out, and all blisters ground out, then hull is again washed with acetone. There are several methods for filling blisters and fairing hull. Check archives of this site and get some good books on blister repair.

After all blisters properly filled and faired then the hull should be treated to a coat of penetrating epoxy, then barrier coat(s), then bottom anti fouling paints.

If this process is put off the result is larger blisters and more difficult to repair. The smelly stuff in blisters is acidic and causes deteriation in the FRP.

Lots of work.

Good Luck.

Ed K

My 87 Oday has the original gelcoat bottom with small size pox or blisters (all less than 1/2 inch and most 1/4 inch size or less and some having fluid when the pox is cut open). The hull was sounded with a phenolic hammer by a professional surveyor and the results were stated as “good/ normal for the hull”. The survey recommendations did NOT include any suggestion of repairing the blisters. The previous owner had the boat moored for the summers in a Wisconsin lake and stored on the hard during winter haulout.

For the previous two years that I have owned the boat, and for the foreseeable future, the boat will continue to be used exclusively in freshwater lakes in Wisconsin, stored on a boat lift during the summer (in other words, out of the water when not in use), and hauled out of the lake each winter for trailer storage on the hard. A good coating of wax (several layers) is put on the hull at beginning and several times during season, while boat is on boatlift.

1) Should I continue to just wax up the hull real good, monitor the blistering through the summer when boat is on the lift and if there is no change- don’t attempt to remove the blisters?

2) If I were to repair the blisters and replace the removed gelcoat with a barrier coat, would I also need to use an antifouling paint too?? Could I just use a good coat of wax instead of antifouling paint on the barrier coat? Because the boat is on a lift or stored on the hard when not in use, I am hoping to avoid the continual maintenance of antifouling paint.

All advice is welcome.