planing mdf

[Dave Brandt]

Is is possible (or wise) to plane MDF? I'd like to change the appearance of some vanity doors and drawers. I was thinking I could save lots of time by planing down the door fronts, cutting out the center, routing a rabbet into the back, and inserting a flat panel. Basically, turning a one-piece simulated raised panel door into a mission-type door. Seems a lot easier than bulding new doors and drawer fronts.

[Sam Yerardi]

I've never tried it but my guess is the glue in the MDF will at a minimum dull significantly whatever blade is being used.

[jason lambert]

drum sander is the way to go but mdf will kill the blades very fast if it is a good plainer and a few doors may be ok. But you will wind up with a very ruff finish that needs to be filled depending on the mdf.

[Ed Blough]

Is is possible (or wise) to plane MDF? I'd like to change the appearance of some vanity doors and drawers. I was thinking I could save lots of time by planing down the door fronts, cutting out the center, routing a rabbet into the back, and inserting a flat panel. Basically, turning a one-piece simulated raised panel door into a mission-type door. Seems a lot easier than bulding new doors and drawer fronts.

I think I would do everything but plane down the door fronts.
Either set the flat panel in deeper to make the door look thinner or find someplace that can handle the panels in a belt sander.

Planning MDF besides creating a dust cloud nightmare will quickly dull you blades.

That said it might be cheaper to buy some replacement sets of blades than pay to have the panels sanded down or make new.

If you do decide to plane the panels do it outside.

[Jason Beam]

No. don't even bother.

MDF Is not evenly dense throughout it's entire thickness. It's softer in the center than out near the faces by design. So if you plane away that top slick surface, you'll be left with a fuzzy mess and it actually reduces the structure of the panel as well.

[David DeCristoforo]

"So if you plane away that top slick surface, you'll be left with a fuzzy mess..."

Not to mention the "legendary" nature of MDF to resist warping, cupping, warping, etc. Once you mess with the surfaces like this, all bets are off. This may seem "easier" than making new doors and DFs but, in the long run, you might be in for at least as much work for an inferior end result.

YM

[Eric Gustafson]

I have used it when setting up a router table and found it machined very well. I read where it is used to make paintable mouldings, but because it dulls HSS knives, carbide is used and that limits the choices for profiles. If you could machine it to a profile, why could it not be machined flat? You would have to use carbide cutters for sure. It seems like it could be done, but I haven't tried it.

[David DeCristoforo]

Eric, I don't think anyone is saying that it "can't be done" because it can and easily. It's just that there are some "down sides" to doing it.....

YM

[Peter Quinn]

The structural support on a molding comes from the substrate to which it is nailed, and it is this support which keeps MDF moldings 'flatish'. Typical MDF moldings have only a small portion of their face molded, and for this most companies typically use Truppan Ultra Lite, not true MDF. Many MDF crowns are actually pressed into shape, not milled.

A door faces different requirements. It is suspended off the cabinet frame from two points of contact (hinges) and must meet the cabinet face with an even reveal in one plane over a considerable distance. A whole piece of MDF intact is barely able to survive this feat without warping under its own weight let alone one whose structure has been greatly modified.

If you try to plane or sand that MDF it will warp, the doors wont sit flat and repainting them will be a nightmare. The machines will suffer great abuse. There is not enough dollar value in any MDF door in terms of materials or labor to make it worth modifying in any event. The reason you don't see CNC flat panel doors with an MDF frame is because they don't work.

By the time you've gone through the trouble to modify a CNC made MDF raised panel door to accept a flat panel you could surely have made a beautiful set of flat panel doors with wooden frames and 1/4" MDF panels with less dust and expense.

I would avoid this fools errand at all costs. Purge your mind of it and start thinking of how you'll make your new doors.

[David DeCristoforo]

"I would avoid this fools errand at all costs. Purge your mind of it and start thinking of how you'll make your new doors."

Hear hear.... well said.

YM

[Cliff Rohrabacher]

While I agree that it's likely to fail for all the reasons mentioned if I absolutely had to do it I'd band saw it off (not plane or sand) and saturate the exposed looser particles with a good thick saturating of epoxy.

And then I'd still expect that it'd fail.

[Dave Brandt]

Thanks for all of the replies. As usual, the knowledge base here is amazing! Looks like it'll be new doors. Thanks again.