Hi guys & Gals.
I have a small problem, I'm repairing some damage to a pair of speaker cabinets for a friend. They were built using 16mm MDF with a 6mm Macrocarpa overlayed veneer. The finished surface (Macrocarpa) was then sanded to 400 grit and two coats of Traditional Oil

He now wants to know if I can put a coat of clear poly over the top to add some sheen to the cabinets. As this product is turps based and dries out hard over time, would this be possible with one of the Wattyl exterior polys?
My local Mitre 10 & Bunnings paint departments don't seem to have any idea, so thoughts from wiser folk here would be appreciated.