Sealing MDF Edges for a Clear Finish

How to seal the porous edges of MDF panels prior to applying a clear finish. March 9, 2008

I have a customer who needs me to finish MDF clear. How would I go about this? The edges are raw and will just suck in the finish.

Forum Responses
(Finishing Forum)
From contributor A:
Sand the edges with 320 and apply 2-3 coats of sealer to them, sanding between coats. You can also use a brush and brush the edges, as it fills them faster and better.

From contributor J:
ML Campbell has a vinyl sealer that you catalyze that has twice the solids as normal vinyl sealer. I think it's called leveler. Works good on MDF edges, which are very porous.

From contributor C:
I sand machined edges on MDF with 100 grit sandpaper (anything finer at this stage seems to be wasted effort), seal with Zinsser seal-coat shellac wiped on with a piece of lamb's wool. When the shellac is sandable, I sand with 150. I then random orbit the flats with 150 and am good to go. As with all other advice, give it a try before you commit an entire project.

From contributor M:
I sand edges with 320 and seal with ML Campbell's AC Sealer. It's a post cat sealer with really good build and sands quick and easy.

From contributor D:
Am I the only person on earth that likes the look of clear finished MDF? I've always thought that it looks good. I always finish all of my MDF shop jigs and fixtures and I think they look pretty good with a nice satin lacquer on them.