Thread: Bulletproof finish for plywood

G'day all,

Recently I find myself making a lot of fixtures and other components for various bits of machinery out of wood. These are likely to be exposed to oil, water and all sorts of other fluids from chloroform to toluene. I get a lot of cheap 19mm 5-ply (ex packing material) which is great to hack stuff together with, so most of this relates to cheap and nasty wood, although when I tried this on MDF it took about 9 coats to get the wood to stop absorbing the paint (without the sealer first).

I've been using White Knight Rust Guard Enamel over the top of Minwax sanding sealer. I don't mind the 24hrs between coats or any of the other baggage that slow curing enamel comes with because after a month it's cured to a point the wood is pretty well protected and takes all the abuse I can throw at it.

I started using the Minwax sanding sealer recently because I was finding I could lay 5 coats of the enamel on and the end grain would just keep soaking it up. I know its not the right product to use, but after hours at Masters and Bunnings it was about the best I could come up with, and it does appear to seal the wood nicely.

I just wonder for this kind of use (where it does not have to look pretty - all mine is Red because I got a good deal on a couple of litres) but needs to cope with both chemical abuse and the weather, what would be the right stuff to use? Once this stuff has cured, about the only thing that turns it to mush is Methylene Chloride (paint stripper or gasket remover) and thankfully I don't play with that much.

I guess I'd be pretty happy just being pointed at an appropriate sealer/primer I could use under the White Knight to stop the wood soaking up the paint. The Minwax seems ok, but it's water based and feels pretty soapy. On the other hand, it dries in an hour and is easy to brush on.