J/30 Class Association Forums J/30 Forum The Boat, Sails and Equipment Blister Repair

I'm on my second season of owning Hullabaloo, Hull #443. After hauling Hullabaloo out of the water last season, I discovered a blistering problem with the hull. As I'm a glutton for punishment, I've decided to take on the challenge of the repair myself. For those that might be interested, I'll be posting the progress of work on a blog at http://j30hullabaloo.blogspot.com/.

Good luck with the blister repair, and thanks for putting the progress on a blog. I added your blog to the class website team pages at this link

It may be a good idea to use a moisture meter on the hull once the gelcoat is off to insure the core is not wet. If the core is wet, your efforts will be for naught as your new surface will likely blister again.

I concur with Al on wet core driving blisters.

I recored Rhapsody from the inside on stbd aft quarter. External barrier coat was good (stripped and reapplied 2 years earlier). The wet core was my source of blisters (look at my blog link). Since I left the outer skin that may have some residual moisture in the glass, 8 blisters reappeared when I hauled the boat this year - nowhere near what it was before I did the core work. I'm grinding these out and refairing those areas. I suspect there may be more that appear next year, but they'll eventually go away. I'll just live with the inconvenience of doing these blister patches for a couple of years since I know the core is now dry.

Note that a moisture meter is a relative reading, not absolute. It also doesn't tell you if you have rotten core. You'll need to take samples. Again, see my blog where I used a circle cutter.

Thanks for the advice. Bill, did you purchase a moisture meter or borrow? If you did purchase, any advice on type/manufacturer? I'll probably ask around to see if someone has one I could borrow, otherwise I'll need to purchase.

The one I used is an older Electrophysics (made by JRC - Japan Radio Company) with traditional analog meter that I borrowed from a friend who is a Marine Surveyor. It pretty much nailed where the moisture was and the boundaries. I think it is model CT33. Check out this link on using the moisture meter.

I picked up the GE protimeter when I bought MADCAP. Pricey, but well worth it. I have been able to monitor a couple problem areas in my deck. The meter reads 0-900. I found that 500 or 600 plus is really wet or rotten and needs repair.

Under 500 I have successful just rebedding the hardware and in some ares drilled 3/4'' breather holes under the deck where I can hide them. The core is still light in color and does slowley dry.

John
Madcap
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