Some years ago I obtained some epoxy wood preservative products from a company in Seattle that specializes in preserving old wood boats (Doctor Rot). The stuff seemed to be really good. I eventually found the manufacturer of the stuff was right across the Bay from me, and visited his "factory". This guy is indeed a mad scientist. The products range from a deep penetrating liquid to a putty to a liquid that solidifies into something that can be sawn, drilled, tapped, etc.
Smith & Co.
For what it is worth.
JBWX