Questions on blister repair

[Capt. Rodbone]

Blister repairs on our new to us 1978 Grand Banks 42 Classic have begun. I’ve only dealt with a couple of blisters on prior boats, so I’ve beat the law of averages however this time I’m dealing with what I’d call a significant amount of them. I feel the seller and a I reached a fair agreement in that post survey, the purchase price was reduced by the average of the three estimates from 3 different boatyards I obtained.

Although many of these are rather large, I was shocked to see that even with the size and depth of those shown, (starboard grinding yet to be done) nothing has been ground to a point where any structural members are exposed or is there any moisture. Although I wasn’t there to witness, I’m told that the ground out areas were dry almost immediately, and have remained so.

My question is am I correct in thinking I allow the repair phase to begin as soon as all are ground out as long as there is no water seeping out?

 

[dsharp]

Hard to say without seeing the damage up close. It looks like someone got carried away with the grinder. I’ve never seen blisters go that deep. You can wash out the voids with acetone or denatured alcohol depending on the type of resin they use for the repairs. Some of those blisters are going to need more than chopped strand mat to fill them. Are they going to remove all of the bottom paint and apply a barrier coat?

 

[BruceK]

They don`t look unduly deep to me. If they are not weeping the grinding depth is probably enough. The Yard should know how to clean them pre repair. On my boat they used graduated concentric circles of mat in epoxy, filler on top, and peel cloth(I forget the real name). If it`s the first repair on the 1978 boat, you should be able to tell if it`s been done before, you might get a good and permanent fix. Barrier coat for sure.

 

[syjos]

I'd check the hull for moisture before proceeding.