I brushed a coat of West System epoxy on my MDF gantry sides. IMO, it seals far better than any paint wood and makes it much easier to get a nice paint job afterwards.
As for soaking any MDF in any water or waterbased fluids, only do this if you want to throw away you parts and make new ones. Unlike hardwood and some plywwods, which can sometimes tolerate getting aa litle wet, water and MDF don't mix. The MDF will swell up, and start to fall apart.
Here's West Systems recommendations for an epoxy moisture barrier, from their website.
Apply a minimum of two coats of WEST SYSTEM epoxy for an effective moisture barrier. Apply three coats if sanding is to be done. Moisture protection will increase with additional coats, up to six coats or about a 20-mil thickness. Additives or pigments should not be added to the first coat. Mixing thinners with WEST SYSTEM epoxy is not recommended. |