They make wood stabilizers . One is called cactus juice I've use wood hardener some by min wax some by Varathaine . I use it on knife scales were I can soak them in it on big pieces you need a sealed vat to put it in, a piece of threaded metal pipe works if you get it big enough . I don't use a vacuum but some of the commercial guys do . It sucks the air out and the stabilizer into the pores of the wood . Some guys just paint it on several coats it soaks in and dries fast . it kind of makes it like it has been impregnated with a plastic and makes it resident to cracking , moisture , ect.