mdf usage

[Sean Hughes]

ALL,

I'm doing my second set of built-ins. They're going to be very similar to my first set that's shown in the picture. With my first ones, i used plywood for the carcasses and poplar for all the rails, stiles and trimwork. I only used MDF for the panels in the doors. On this second set, I was thinking of using MDF for the upper rails and stiles around the bookcase portions. Would this be a problem? If not, can you join the rails and stiles with pocket screw? If not pocket screws, what's the best option?

Thanks!!

[frank shic]

i thought i was clever a few years ago when i built several large closets using MDF for the rails, stiles and the panels but the dust was extremely annoying and the edges ding up really easily. great looking project btw!

[Joseph Tarantino]

mdf could be used, but it does damage fairly easily, especially sharp edges. and cut edges needs to be "sealed" before finishng, or they won't look the same as mdf's nice flat surface. sealing can be done with joint compound or a 50/50 mix of wood glue and water. "Nahm" has used pocket screws to join stiles and rails, provided they were wide enough to accept two screws. he's also used biscuits and mortise and tennons, and i suppose dowels would work also.

[frank shic]

i will say that it's nice to not have to worry about preparing stock apart from cutting it but ARGH the dust....

[Bill White]

You're gonna have probs using MDF for rails and stiles. Fastener retention, M&T construction. If you're determined to use it, try the moisture resistant MDF. Heavier but tough.
I'd use poplar for paint grade stuff. That's just my take.

[Sean Hughes]

Thanks all. I figured as much but thought I would ask the collective.

[Jim Rimmer]

Looks like you've decided bit I'll add my 2 cents. Don't argue with success. That is a nice looking built in that you already have and there is obviously a lot of work involved. You know it looks nice - just repeat it.

[Peter Quinn]

You might use MDF for that wide top rail, I'd probably edge band the bottom edge of it with 1/8" of solid poplar to make it tougher and easier to paint. This would save you from having to prepare a wide poplar top rail. I'd stick to solids for the stiles, more problems than its worth using MDF for that application IMO. I like biscuits for an MDF to MDF or solid stock to MDF connection, I prefer pocket screws for face frames using solid stock as long as they can not be seen. If they are visible I might go with biscuits or dominos or dowels instead. On open shelving I prefer the joinery be blind.

[Chris Padilla]

The screws to use with MDF are called confirmat screws. Check out McFeely's: http://www.mcfeelys.com/search/confirmat

That said, I'd stick with poplar as you did the first time. MDF will need sealed (shellac, Sealcoat) before painting to look right and I dunno about the durability. Put it this way, I will never used MDF for baseboards again...finger-jointed pine at the minimum with a hardwood working better (poplar, birch, etc.).