Technically the EG can pass through the WBP Phenol Formaldehyde glues used in marine plywood construction. However, in the 'real world' where EG is applied by hand (not pressure) and is absorbed into the wood rather than forced into it, I doubt that enough of it actually reaches the core plies to treat them effectively against rot.
With multiple applications it may get into the core plies enough to poison them against rot, but who applies EG multiple times? I put it on once, then I let the wood dry thoroughly before I start gluing it. Even if it only treats the face plies that's fine with me. Epoxy will never get past the glue layers and into the core plies anyways, so by using EG I'm basically treating my face plies and possibly also enhancing the epoxy's bond to those plies.
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Note that Copper Naphthenate is likely to be longer lasting and maybe even more effective against rot than EG, but as far as I know no one has ever done any testing to determine CN's effects on the epoxy-to-wood bond ...
The guys at Merichem think that because the carrier in their water-borne CN formulation is based on amines (which exist in most epoxies) that a 'chemical affinity' might enhance the bonding of epoxy to the wood after a CN treatment. But they are just theorizing about this, and they haven't done any tests to confirm one way or another, so the effects might be just the opposite for all they know.
I would be interested in seeing some tests in this regard, but I cannot do them myself because as far as I've been able to determine they do not have any CN in this country nor do they allow it to be imported. Too bad because termites eat everything here and CN is an extremely effective (and inexpensive) termite pesticide too.
,,,man i had a headache for 3 days.
