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

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.