If you are using MDF Baseboards/ casing... please read

[Jesse Busenitz]

I've done trim carpentry on tons of new houses, some very high end, and they still used MDF which IMO is really stupid, as that stuff is just downright nasty.... Ok it does have a few apps.... but very few... but we never primed the ends, insides or nothing.... We always used coner blocks on the inside, but I've never heard of the BB shrinking that bad... Oh and none of these houses were "climate controled" so the material was the temp and humidity I'm sure swung quite a bit, but we never had any problems that bad. Cept if we cut twice and it was still too short lol.

[keith micinski]

I am surprised no one has mentioned the box store pre primed pine trim that is finger jointed together scraps usually shrinks about an 8th of an inch a foot. I have way less movement with MDF then that garbage. I also think MDF gets a bad reputation because its not "real" wood but find it is not a sub standard product at all.

[Mel Fulks]

I think the use of corner blocks, if it is just to save labor, is a bigger problem than mdf. I would not describe such a place
as high end. Mere high square footage with weak design usually makes a low end house when it is resold the first time.

[Mel Fulks]

Keith,I would have found your statement about trim shrinkage hard to believe had I not bought a pine octagon window
recently. The trim pieces were only about 10 inches long, and opened up! I don't believe it was kiln dried, if it was kiln
dried it was not done properly.

[Mark Wooden]

+1 with JeffD and Mel. Yagetwhatchapayfor, pennywise, poundfoolish, etc., etc.
I do use MDF, but I wouldn't build a cabinet from it, only the paint grade panels. I did make a chair rail conge and cap of MDF for a builder once. I sanded it 220 smooth, sprayed 2 coats of shellac primer and saw it about four years later; looks like crap and I did the walk of shame upon leaving. Not good for running trim IMO.

[Yonak Hawkins]

Hi Erik,

I've also read that using MDF lite won't "pucker" around nail holes like regular mdf. Finishing those nails holes is another topic altogether in normal MDF.

Mitch in Canada

Ultralight MDF is too soft for baseboards in my opinion. Maybe regular MDF is too, according some posts in this thread.

[Jak Kelly]

My brother made signs for the state, I think they we used near a lake area, to mark the "boat ramps", "picnic areas"...........
He was surprised about the choice of MDF as well. The guy running the job told them to just make sure you seal all the edges with a good paint. My brother thought the signs would need replaced in two years or less, he went by there five years later and said the signs looked almost as good as the day they were intstalled. Yes they were the same signs.

Also, on sanding MDF, I thought that was a big "NO-NO"? As when you sand you remove the hardened, baked-on finish??

[John TenEyck]

My brother made signs for the state, I think they we used near a lake area, to mark the "boat ramps", "picnic areas"...........
He was surprised about the choice of MDF as well. The guy running the job told them to just make sure you seal all the edges with a good paint. My brother thought the signs would need replaced in two years or less, he went by there five years later and said the signs looked almost as good as the day they were intstalled. Yes they were the same signs.

Also, on sanding MDF, I thought that was a big "NO-NO"? As when you sand you remove the hardened, baked-on finish??

I'll bet those signs were made with MDO, not MDF. MDO = Medium Density Overlay, which is exterior plywood with an impregnated paper layer on both sides. Very nice stuff, and sort of standard issue for many exterior sign applications.

John

[Jak Kelly]

I'll bet those signs were made with MDO, not MDF. MDO = Medium Density Overlay, which is exterior plywood with an impregnated paper layer on both sides. Very nice stuff, and sort of standard issue for many exterior sign applications.

John

You may be correct on that, I'm not sure, as he said it was MDF. Being an experienced builder I assume he knew what materials he was talking about, but once again you may be correct?

[Grant Wilkinson]

I made hold downs for my scuba tanks from exterior MDF, not MDO several years ago. I realize that this is a different product than the interior MDF. The racks are on a boat; they get wet, they get banged around. They are still as solid as when I first cut them.

I believe some of the problems with MDF in general stem from the grade used. I know that the product that I buy from the BORG is not the same as the product that I buy from a local lumber yard.