Blister Repair

[REBrueckner]

There are many posts here on blister repair, many of them NOT FACTUAL. That is, much of the information is inaccuarate!! There is only ONE way to insure a bottom is ready for repair after stripping, blister removal, or whatever: a moisture meter. Hotvac, while a potentially accelerated way to remove moisture, still needs moisture readings to determine when the hull is actually dry. And so does every other drying method.

Ask any reputable repair facility how they determine when repair may be undertaken. Or See instructions for products such a Interprotect. They'll specify a permissible moisture content. Well intentioned comments from owners such as "..I used a dehumidifier for three days", or "..I let it air dry for two weeks" are utterly ridiculous.

Also note, a moisture meter CANNOT be used to determine if a recently hauled fiberglass hull needs any work. Ask any reputable surveyor: 99% of bottoms, unless maybe brand new, will read at or close to 100% for weeks or months after haulout.

 

[Eufaula]

Why do blisters have to be repaired as NEW if the boater is not a speedster and not in need of a smooth hull? James

 

[67hat34c]

surface blisters do not need to be repaired. however structural blisters do. that is when the water soaks into the fibers. it will turn red, this is acidic and is the result of resins breaking down. i think it is a good idea to repair blisters to keep them in check. typicaly grinding them out, letting dry and filling with west system putty is all you need for minor ones.

also smoother bottom will make a little difference in performance. we just had ours sanded down to the gel coat, we gained a little speed. went from 17k cruise to 20-21k cruise, also changed props.

 

[MikeP]

Interesting comment re moisture meters and the opposite of Pascoe's view that moisture meters are essentially useless.

Life is so confusing.

 

[Genesis]

My view is that moisture meters are worthless as well. That comes from actually attempting to use them. They cannot sense what they cannot get to; moisture at the surface does not necessary mean that the laminate is saturated below the probe level, and in the case of fiberglass, saturation does not mean imminent failure - nor does it mean the boat WILL blister.

Blistering is a lot more complicated than that.

 

[Maynard Rupp]

I guess we do have a few advantages living in the Great Lakes area. We haul our boats in October, most go to heated indoor storage, and we don't launch until mid April. Last fall we stripped and ground our bottom. In late March, after having 5 months to dry, we checked the moisture content and were pleased that the meter hardly moved. Now the interprotect and VC-17. It sure helps to let it dry for months instead of days or weeks.

 

[REBrueckner]

Pascoe says moisture meters are useless for haulout survey purposes because almost all hulls are wet for weeks and usually months after hauling.

 

[REBrueckner]

Moisture meters are a tool. If you don't know hopw to use a tool you will be unable to get desired results. Don't blame the tool. If you doubt this advice, just ask experienced professionals. They cannot be used for survey quick out purposes-Pascoe is right about that. Virtually all hulls will be 100% wet for weeks and usually many months after haulout.

 

[Captned]

Interesting thread. Moisture meters have a great ability to help find wet core material in decking, cabin house sides, wet stringers, etc. I use one all the time. A JR Overseas model. It gives you a heads up, not a hard finding. You can follow that with a phenolic hammer or drill if you are brave! As far as blisters go, can someone show me a vessel that has suffered "structural blisters" or any amount of blisters and sank or was rendered unusable ? I have seen boats with thousands of blisters that are still quite seaworthy. Blisters should be repaired at annual haulout and condition monitored. Peel if you want. I do about 50 or so every year on my 78 46'. No big deal.

My 2 cents.

Captned