I hadn't thought about the vacuum sucking in water or cloth creep. Off-hand I would think if the wood is open to the vacuum it would get at least partially filled with epoxy. With low viscosity epoxy the trapped cavities should not remain at a vacuum. While the additional epoxy sucked into the wood may increase the weight, it should make an excellent bond.

While I agree that low viscosity epoxy should be used, I don't think there is much risk of the cloth moving far. Unlike in a traditional highly polished mold, the cloth is against relatively rough wood. There is quite a bit of friction not to mention splinters and snags.

> You would have to be very carefull about the vacume bagging sequence for a
> wooden boat because you don't want the hull/wood to be under vacume when
> all is said and done. Imagin developing a pin hole leak below the water
> line, you wouldn't simply have water wicking in, it would be sucked in at
> one atmosphere! It could potentially suck in enough water that you could
> never dry out again.

> What ever vacume method is used you want the to wood to be a ambient
> pressure.

> Having said all this I think that the best approach would be to not vacume
> bag but switch your glass to aircraft 181 cloth. This will allow you to do
> a hand layup that really snugs up to the wood and doesn't soak up as much
> epoxy due to the tighter weave.