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MDF interior doors--Should I make 'em?

Flash28's picture

So I'm finally to the point of finishing out our house and am wanting to use interior doors of an atypical design in terms of panel layout and proportion.  I also would love to have 1 3/4" doors, but funds are very limited.  I know that TruStile has been making MDF doors for years, so why couldn't I?  I'm a seasoned renovation contractor who's a finish carpenter at heart, so I'm confident in my skills.  I'll be building the entire kitchen and numerous built-ins.  My latest idea for these interior doors is to build frame and flat panel using a sheet of 1/4" MDF cut to size (say, 32" x 84") as the core, and then laminating strips of 3/4" MDF onto both faces in a frame and panel configuration.  I'd also machine both edges and glue in a solid strip of poplar, like TruStile does.  I could machine the inside edges of the frame members to make them look like cope and stick joints, or I could leave them square and apply a bolection moulding.  It seems like I'd end up with flat, stable, custom doors at an affordable price.  I should mention that part of what has spurred this train of thought is my need for some custom height doors in the upstairs bedrooms and the exorbitant cost of having those made (not that I wouldn't charge at least as much, but we're broke right now).


At any rate, any insight would be great.  I don't want to be short-sighted in doing this in terms of durability, especially with three young daughters in the house.  Would they clobber these things?

Thanks-- Flash28

Is 1/4 inch panel a bit thin? (post #207301, reply #1 of 6)

Seems like a 1/4 panel is thin.  Not sure, just sounds thin. 

Do you have kids?  I can see a hole in one of those doors as I sit here thinking about it.

Not sure what you mean by inlaying a popular strip.

interesting idea (post #207301, reply #2 of 6)

Sounds feasible, I've built countless doors out of far less stable materials including lots of sandwich doors... You might consider using 3 layers of 1/2"  

MDF glues up wonderfully but is rather expensive currently and at the end of the day you still have a sawdust plank door.

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thanks (post #207301, reply #3 of 6)

Thanks for the feedback.  I agree with the first response that a 1/4" panel sounds thin, but I'm thinking that the frame overlay will strengthen it and will actually leave the 1/4" panels no wider than 7 or 8" in most of the doors.  We currently live in a 1930 house with all its original doors which are 2-panel made with 1/4" plywood.  I realize it has much more impact resistance than does MDF, but the panels in these old doors are all at least 20" wide and all still fine. Incidentally, we got the full history of this house from the previous owner when we bought it, and I know that at least three boys were raised in it with all doors surviving.  As for the sawdust plank issue, I agree and am concerned about how much of a beating the door edges with incur, but I must also say that any of the MDF casing I have milled and installed here is wearing very well.  Plus, TruStile presents its MDF doors as a premium product, and many outfits are making cabinet doors of MDF.  I dunno...

I've several thoughts (post #207301, reply #4 of 6)

I've several thoughts regarding this idea:

By joining the "rails and stiles" you will add structural integrity to the assembly. The weakness of the 1/4" panel will then be moot.

You must take care to glue everything well. The rails and stiles must be well bonded to the 1/4" panel. A vacuum press would be invaluable here. 

It will be a lot of labor. 

You will create an unholy amount of nasty dust.

mdf is very heavy... I hope you realize this and are strong enough to work with it. 

You will need a really flat assembly table. Otherwise the doors will be warped beyond fixing. 

At the end of the project you will have mdf doors. And I don't care what any manufacturers brochures say or how much they insist that they create a "premium" product... you will have fiberboard doors, not wood doors. My advice is to go to the local salvage place and get some really cheap, and temporary, doors to make the bedrooms private. Then, as finances allow, make some quality wood doors using real rails and stiles and real wood panels. Outfit them with quality hardware. Doing these one at a time won't kill you physically or financially and at the end of the project you will have added real quality to your home. 

I know, I know (post #207301, reply #5 of 6)

Thanks for your thoughts.  I've been mulling things over trying to rationalize doing this rather than getting/making solid doors.

The weight of the MDF isn't an issue.  I work alone professionally, so am used to all the wrestling.  Plus, I always split sheets with a circular saw and long straightedge before I ever shove them through the tablesaw. 

I have had very good results in milling my own trim of MDF, so long as the critical areas are protected and the trim receives good coats of paint. 

I've figured out how to protect the vulnerable edges of the doors with solid wood panel molding and solid edges along the doors.  These solid edges would also give me good purchase for the hinge screws and lockset screws.  But then again, of course, how foolish is it to make doors of material that requires so much protection?  I keep waffling...

I'll ponder it a few more days, but I really do appreciate your dose of reality.  I'll take it into account.

 

Regards  --Flash28

 

Hardware: The Weak Spot (post #207301, reply #6 of 6)

The doors will be HEAVY. How will the screws hold? Pay extra care to this detail; I suggest, at a minimum, metal screw thread inserts ("thread-serts").