Acetone to Aid in drying wet plywood core

[team karst]

Originally Posted by Dalestr

Acetone can dissolve, soften cured polyester resin …..

Maybe, if given a tremendous soak time. The story changes using methylene chloride

[I14]

I'm not sure the builder would have used polyester, rather than epoxy, for the adhesive between the outer laminates and the plywood due to the rather random adhesive qualities of polyester onto wood but even if they did fully cured polyester would take a long time to soften with acetone. Acetone mixed with water form what's called an azeotope and boil as a mixture, the acetone will not separate from the water. The danger of explosion exists from the outlet of the vac pump so if it's in the open air as shown and away from any ignition sources then it should be safe enough

[Moosemiester]

Once plywood gets wet, and the bacteria goes to work, it’s structural qualities go to near zero. Dry it out, the bacteria goes to sleep, and what you have is so weak you can crumble it with your hands. Pump in a massive amount of epoxy and you have something brittle that doesn’t flex, in a stricture that’s designed to be a torsion box, not a rigid member.

It’s easier - and far better - to replace the core. Unless you are planning to get rid of the boat, fool a surveyor, and make it someone else’s problem.

When I restored my cored vessel I found blob after blob of epoxy floating in rotted wood from previous owners who attempted what you are doing.

It’s your boat, do what you want [emoji3]

[wyb2]

Originally Posted by Moosemiester

Once plywood gets wet, and the bacteria goes to work, it’s structural qualities go to near zero. Dry it out, the bacteria goes to sleep, and what you have is so weak you can crumble it with your hands. …

Depends how bad it’s gotten. My old boat had pretty badly saturated side decks. When I took a coupon of the inner skin to investigate, I was surprised how much I had to pry and fight to separate it from the wet plywood.

My current boat has a bunch of areas that peg the moisture meter, but no dripping brown liquid, and only one spot that has delaminated. If I can dry it out (I have succeeded on one large section so far) and keep it dry, no core replacement will ever be necessary.

[GordMay]

FWIW:
Acetone and pure water are soluble in all proportions; they are completely miscible.
The reason for this behavior is the formation of hydrogen bonding interactions between the oxygen atom of acetone molecules and the O-H bond of water molecules.
However, when salt is added to the mixture, the resulting Na + and Cl- ions interact very strongly with the water molecules through ion-dipole forces. These ion-dipole interactions are much stronger than the acetone-water hydrogen bonds. As a result, the acetone molecules are forced out of the aqueous phase and two layers are formed: a lessdense acetone layer on top and a salt water layer at the bottom.
Obviously, acetone and salt water are incompatible and therefore immiscible; they do not mix in all proportions.
➥ https://www.job-stiftung.de/pdf/vers..._Saltwater.pdf

[Chotu]

Originally Posted by GordMay

FWIW:
Acetone and pure water are soluble in all proportions; they are completely miscible.
The reason for this behavior is the formation of hydrogen bonding interactions between the oxygen atom of acetone molecules and the O-H bond of water molecules.
However, when salt is added to the mixture, the resulting Na + and Cl- ions interact very strongly with the water molecules through ion-dipole forces. These ion-dipole interactions are much stronger than the acetone-water hydrogen bonds. As a result, the acetone molecules are forced out of the aqueous phase and two layers are formed: a lessdense acetone layer on top and a salt water layer at the bottom.
Obviously, acetone and salt water are incompatible and therefore immiscible; they do not mix in all proportions.
➥ https://www.job-stiftung.de/pdf/vers..._Saltwater.pdf

Not to mention just pouring it into a hole in the deck is not exactly mixing it.

[team karst]

Denatured alcohol better? It mixes with water.
My ear beer uses alcohol as drying agent.