MDF Vs Wood

izzy

I grew up in a cabinet shop and I have always preferred wood over medium density fiberboard for built ins and such. I am doing a new house trim job with some built ins and I am considering using the mdf. Any pros or cons and how well does this stuff paint? Once you cut and router are you able to sand your machined edges smooth or will they remain a little fuzzy? And how does the mdf trim compare to wood trim?

AndersonsWworks

I guess it depends on what you are using the MDF for. I have had good luck with MDF base. The crown can be a little tricky to cope. Chair rail works well for me also. I get everything preprimed and it takes paint very well. I have tried everything to get the edges of MDF to paint well and found the answer on this board. Coat the edges with varnish and then sand. The varnish locks the fibers and leaves a nice smooth surface.

Rocky

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Rustbucket

MDF takes paint really well. Just seal the edges with a little glue mixed with water to thin it, followed by a light sanding. Don't use it in kitchens and baths. It doesn't like moisture much. I would use plywood for shelves if they are adjustable. Make sure you pre-drill all holes, and use confirmat screws for joinery.

Chris G

Takes paint lovingly.

There was a good article in Fine Woodworking a few years back about MDF trim. Basically, it pointed out that all the edges and contours were softer and more rounded than comparable wood pieces. MDF doesn't allow crisp edges in profiles. The result is that trim pieces can look a little blurry. Kind of like 20/30 vs 20/20 vision. Not a big deal though, especially if you're blind as a bat.

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TBFGhost

I use it all the time and whenever I can. I stopped coping MDF...it does not cope well. I miter and glue the SNOT out of all my corners using Titebond Molding and Trim Glue or Elmers Gel Woodglue. Its thick and does not get wicked up by the MDF.

MDF paints great and any time you expose any "end grain" use 20 min hot mud. I keep a bag near and mix up little batches here and there, smear it on with a small putty knife or my finger. Sands down to glass. If you let the MDF acclimate I found it to move much less then pine. However I do find if I hang it right from my yard it will shink up some...nothing a little caulk won't fix, but I would rather let it acclimate and avoid that all together.

Some people hate it. I love it. It dents less then pine.... Hit pine with a hammer, what happens? Hit it MDF with a hammer what happens? On the face, the pine dents WAY more then MDF and on edges I find it to be near the same.... I don't use it on casing....I try and use poplar there...

This is mostly MDF sheet goods...the casing in PFJ Pine...


This is a combo, but all the flat parts and crown are MDF


This is all MDF

woodworkbykirk

after the painters came back to do their touchups on our current job we made the decision to stop using mdf for casing and jambs. the reason being nail holes, it swells up at nail holes when painted, typically it mushrooms up and can be sanded down before painted but it comes back. on our job everynail hole jumped right out after it was filled and painted.

for routing we avoid dealing with profiles we stick to 1/8 radius for cleats, and 1/4" for shelving then hand sand with sanding pads. this turns out fine but any kind of ornate profile comes out rough.

our next project were going to be using pine for everything other than closet shelves

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AHC

is MDF harder on saw blades then real wood?

William James

First off. Wow, nice work TBF! Way to plug that craftsmanship in there.
MDF is decent for trim work. Have done base and casing with it and seems to work out fine. I haven't had a problem coping it, just need to shave the fuzz. It's more flexible than wood. And shouldn't move like wood "if acclimated." But as far as cabinets go. I've used it on doors but not for the case, and only with piano hinges. Don't trust it to hold with 35mm. It routs well with 1/4 boxcore bit. but doesn't have the holding power like wood. The wood will close on a nail, but the MDF doesn't seem to. Bottom line it's not as strong as wood.

crovello

I use it for panels but don't like it for casing or base. I find it to soft. Drag a vacume hose around the corner and thats the end of a nice clean corner.

Also I want to smell wood when I am doing finish work not suck on brown dust.

It does glue and paint well.

Cache

I use both products on every house. All houses are high-end, 4,500sf+ and finish carpentry is my specialty.

MDF is reserved for certain locations.

Panels with wood frames, crown moulding, out-of-reach window casings, painted architectural beams, etc.

Absolute no-no on base except one situation. 1x6 S4S with a wood base cap and room has all inside corners and carpet. Under those circumstances the 1x6 must be primed all four sides and it is acceptable for the really tight budget. MDF flat stock has exceptional face strength, but incredibly poor edge strength. A vacuum hitting the face of the 1x6 MDF will rarely leave a mark, where it would otherwise dent 1x6 pine or poplar.

ANY moulded profile in MDF is weaker than its wood counterpart. Absolutely not acceptable for door and reachable window casings with edges exposed.

Basically, any time only the factory face is exposed, it is a great product. Also, large built-up crowns won't crack out from movement as much as wood. I mill my own wood moulding, so my customers rarely opt for MDF except for panel work.