DIY Doctor UK DIY Forums

Hi.
Has anybody used old engine oil to treat plywood? I'm just about to renew the wooden panels and floor of my trailer with wbp plywood and I was about to go and buy some fence treatment, when my partner suggested using old engine oil instead. I know the plywood is water resistant, I just wanted to apply something so water doesn't cling to the wood. Could be a good idea but I'm concerned that the oil will have a detrimental effect on the the glue holding the plywood together. Any thoughts?

Yuck! I can't think of many less pleasant ideas to be honest!

I tried it about thirty odd years ago to rot-proof some fence posts and it was a pretty awful job then. I can't think of the slightest thing to recommend it now.

Rather than fence paint, get some wood preservative. It doesn't really colour, but does penetrate well.

Best of all would be to get proper marine ply which should last a long time untreated, particularly if you keep the trailer covered when not in use. In my experience WBP ply isn't!

Sounds disgusting!! Like oddbod said use marine ply. Slightly more expensive but should give you 10yrs. I use marine ply for the floor of narrow boats. I cut all the sheets before hand and bitumen paint the underside of the ply and all the edges. This keeps the moisture out and gives it a good long life. The same process can be used for your trailer. Dont buy bitumen paint from a specialised paint shop, its too expensive. Buy it from a builders center. Its the same stuff they use on roofs. Use a cheap roller to apply it with then throw it away. Hope this helps. Leo.

I highly recommend used motor oil for finishing exterior wood! I have done this very thing, with much success. I have a flatbed trailer that has a plywood deck. The plywood was getting very dry and beginning to crack and split. I tried coating it in used motor oil as an experiment. It soaked up the oil like a sponge and I actually liked the dark brown, walnut appearance. Then about a year later it started to look dry again so I gave it another coat of oil, this time a much thicker, liberal application. Now, 3 years later, it still looks great! And it's very waterproof as well. It looks like a railroad tie and like it won't need to be refinished for years to come! I can speak from experience, this works and works great if you don't mind the dark brown look.