How to seal mdf edges? - festoolownersgroup.com
It dries very hard and is also sands to a powder. My steps would be: 1. Prime the edges with BIN (you don't have to be perfect as it will sand easily.) 2. Sand lightly with a soft sanding block or profile to reduce the fuzz and BIN. 3. Clean up dust and coat again. Do as many as you feel get you the edge you want. A couple of notes.