MDF for Painted Projects?

Medium density fiberboard (MDF) has some advantages over wood for paint-grade cabinetry. This discussion looks at when to use MDF and also at fastening and related issues. April 6, 2011

I have been using paint grade maple ply or paint grade solid maple for my painted projects, but recently began adding MDF, as there's less filling and sanding between coats and the final finish looks so much nicer. Some door suppliers, like Walzcraft, have added most profiles in MDF for a savings of a few dollars per square foot. I'm thinking of making the switch to all MDF on the next painted job. What do you guys use and what would be the best fastener for this material?

Forum Responses
(Cabinetmaking Forum)
From contributor O:
I use all MDF, except where a face frame is needed. I build frameless but when a bookcase, etc. calls for a frame, I use maple, poplar, alder, ugly cherry... whatever is on hand. I switched over awhile ago to all MDF doors and have not had the finish issues I had before with wood doors.

From contributor R:
I use MDF for painted doors with great success. I also use it for capping on pony walls and for stair hand rails. The one issue which drives me insane is that I can't seem to find a filler that works well. I usually use a latex spackle but it seems to sand a lot more than the MDF. Once painted, the joints sometimes show through. I usually have to roll the paint on, which hides it a little better, but takes longer.

From contributor J:
Contributor R, I use lightweight Bondo. It fills well and sands relatively easy.

From contributor S:
I'll use MDF for painted surfaces so long as the edges aren't subject to strike damage. Panels on doors, rails, stiles, panels on wainscoting, but not the top rail if it protrudes past the panels, and not for the baseboard. I build very little that is frameless, but when I do I use plywood. I feel like MDF will sag over time, even though I'll admit I haven't had the nerve to send a job out in it to try.

Where I have the decision left to me, I will use MDF for crown window casings. I cringe at using it for baseboards and door casings because of the damage I have seen done by vacuum cleaners and the like bumping it in normal use.

From contributor H:
We also use MDF. We use 1 1/2 staples and 1 3/4 inch zip screws to build the boxes. Bondo filler to cover holes. We use Blum Inserta hinges exclusively and they hold well in the MDF.