Is your bottom blistered?

[Boatsb]

No gelcoat is safe from blistering. The change was probably due to the addition of barrier coats from the factory or with the first bottom paint. I see new boats with blisters all the time and most of them do not have a barrier coat applied. Some dealers save money by not preparing the bottoms properly before painting. It bites the customer in the but later but the dealer doesnt care.

[captddis]

Alot of the problem is/was because builders used cheaper polyester resin for lay up and put a coat of Vinylester on as the last coat. Once the vinlyester was sanded through or otherwise compromised, the polyester blistered.

Anyone ever notice that the cheap boats built with chopper guns rarely blister? That is because there has to be a void or un wetted out section of glass for the blister to form.

The new boats built using vacuum bagging or any of the new systems and using more vinylester, will probably not blister. Because of the lack of voids and a complete wet out.

[bobk]

Blistering is a very complex subject. The best information I'm aware of was generated by a couple of acedemics at U Mass if memory serves. You can google the topic and find the reports.

A large factor in this is the use of ortho phthalate resins. The chemistry of these is such that they are prone to hydrolysis.... but they are the cheapest of the polyesters. Iso phthalate resins are more costly but resist hydrolysis better. Vinyl esters are the best and most expensive. They also make an excellent, weatherable gelcoat. NPGI (neopental glycol isophthalate) polyesters make a super weatherable gel coat. If I were fortunate enough to build a new boat, I'd use an NPGI gelcoat and VE for the underwater fiberglass.

Bobk

[saltshaker]

Jack,

Our 1988 Hatteras 65C has a few dime size blisters in localized areas.
Not worried about it though, our 1972 48 Yachtfish had some blisters, but they never grew or multiplied over the 5 years we owned her.
Btw, what's your hull number? Ours is HADAT319K788.

Pete

Pete,
Sorry I missed this before. my hull HID# is HATDA330D888. Hope your enjoying the new toy.