I have a lot of Rustins MDF sealer here actually.. I was just a little worried about applying it and the MDF swelling.. then needing to resurface it and undoing the work of the sealer by taking off the top layer.. I guess if I apply a few coats, it'll seep in a lot and then when I resurface it, I'll still have a good layer of protection. It's probably worth it for the T-slots alone anyway.