I am considering useing MDF for trim in my new house. The trim detail is very simple with the headers over windows and door being a little proud of the side trim. Something like 1/2″ x 4″ for the sides and 5/8 “x 5” for the headers. All butt joints.
All the trim will be painted. The thought is that it will save some cost but mainly that it will be straight, easy to work with and paints well.
Any thoughts?
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MDF is perfect for the application you're describing. The only things I don't like about MDF are its weight (heavier than wood) and that it's very weak in bending. However, there are no structural demands on trim, so I use it all the time for that purpose.
Just be careful with MDF in the bathroom. If the baseboard is against the tub, it's a wet enough environment to cause it to swell. I've had that experience once or twice in the past. Now I always use wood whenever it's in an area that might get splashed from time to time, and feel confident using MDF everywhere else.
One final thought: I'd suggest using 1/2" and 3/4" stock (as opposed to 5/8"). The 1/8" shadow line is so small that if there are any incongruencies in the wall surfaces, it can just about disappear. Besides that, my local lumberyard doesn't stock 5/8", so using 3/4" will avoid the need to run stock through the dimensional planer.
Don't do it unless you plan on doing something to treat the cut edges, which will eat up all the material savings. It also doesn't nail very well, it creates these little crates with riased edges. I think you'll be happier with poplar or I even used wormy maple once. That wormy maple was a joy to work with.
MERC.
What type of finish nailer do you use? I use a Bostitch 15 ga. N59 w/anywhere from 1 1/2 to 2 1/2 finish nails and have never had that raised edge issue you experienced.
I use a PC 15 ga finish nailer. Maybe it's the type of MDF. I manufactured the trim from sheets of MDF, I can see that the premade trim might be a different kind of MDF?
All I know is that the next time I trimed a room, I used hardwood and it costs about $125 instead of $25, but I enjoyed working with it a lot more.
MERC.
Maybe thats it. I believe the pre-made trim is more compressed and thus may be harder. It is also effectively "sealed" from the factory by being pre-primed (at least on the face-side).
The responses that I have so far are what I have heard before about 1/2 of people Love MDF for trim and 1/2 hate it. I'll be using a nail gun which helps with the nail hole problems but I'm not sure on how those who love it deal with the edges.
Any of you MDF lovers have any tricks?
Let me preface this by saying that I didn't do the work, the trim guy did....lots of custom cabinetry and such made with mdf (including raised panels to match existing birch cabinet doors); on the edges, they painted all the edges with a good sealer (BIN, from Zinsser I do believe)...with a good sprayed paint finish, you honestly don't know that it's mdf. The trim guy was adamant that BIN was the only sealer he would use on mdf, and since it worked A1, I wouln't bother to try anything else.
I'm not understanding the "edge" problem. Is it a painting issue? Could you elaborate?
As I understand it any cut edge of MDF is very porus and looks Fuzzy even with many coats of paint. I've heard that some cabinet makers use a sealer on the edges (see other responses) to deal with this.
I am wondering what folks are using on the cut edges and how well it works for them.
I see your point now. Yes, it does seem to be a bit more difficult to get a nice finish on the edge of a piece of MDF trim. However, since I only use MDF for trim, it hasn't posed a huge problem for me, I guess. That is, the edge of a door casing is a lot less visible than the edge of a kitchen cupboard door.
With that said, I've seen lots of MDF cabinets with very glassy finishes. So there must be a way to seal it and get great results, as others here have indicated. (Painting is not something I generally do, so I'm less familiar with that component of the project.)
Well, we aren't pros so take this with a grain of salt. But in the rooms we've trimmed with MDF the 'edge' issue has never come up - we put returns on the trim where it might normally be exposed edge, e.g. the trim over the doors and windows. Since end grain of real wood takes paint and finish differently, I probably wouldn't have stressed over it even if we hadn't used returns. We never had a problem with nailing, but that might be because we used pneumatic. The only thing I didn't like about the MDF was that it is easier to break (2 people should carry the longer pieces or it can snap) and dent.
There was an article in FHB about the edge issue some time ago. You must use VERY sharp tools. Keep extra bits and blades on hand.
Prime the cut edge with Bin just like another post said. Sand as needed and paint. I've got book cases for my daughter's room made of MDF and they took surprisingly little prep to get a good finish.
Oh yeah, get the light stuff. It'll save your back.
There are a lot of tricks to detail MDF.
Some use thinned glue, like Calvin.
Some use drywall mud.
BIN is another common one.
Realize that the cut edge of MDF will absorb a water-based product and gain a texture, like sandpaper. When priming I always use an oil-based primer. That eliminates a good portion of the problem right up front.
For small exposed sections of MDF core, after wiping it down with a tack cloth I just oil-prime, scuff sand, then two coats of paint, scuff sanding after the first coat.
It's perfect.
I always use oil-based paint on trim and cabinetry, but you could use oil of latex. But always use an oil-based primer.
If I expose a good portion of MDF core and the exposed section wil be in a high-visibility area, as it would when milling a raised panel, then before priming I'll use Bartley's Pore Filler. I brush it on, after it dries it sands glass-smooth and "firms up" the exposed core. The extra step only takes a few minutes per panel. Then oil prime, two coats of paint...
It's perfect.
I've never had a problem with volcanoes when air nailing. 15 ga.
I use a lot of MDF. I've come to recognize its strengths and avoid its weaknesses.
But I'll alway and forever hate the dust.
I cope 1/16" or so from the edge and finish with a sanding drum on my Dremel to prevent the fuzzies and breaks (wear a mask).
The awful thing is that beauty is mysterious as well as terrible. God and the devil are fighting there, and the battlefield is the heart of man.- Fyodor Dostoyevski
I've found that a small nailer (18 ga.) is ok but a 16 ga leaves large holes to fill. Given the limited lenths to mdf, what are you using for base?
For the limited lengths I was planning on using scarf joints. The walls are pre-manufactured SIPs so they are pretty true. I have heard that you can use biscuts too.
Depending on what you want your baseboard to look like...... You can get 16' lengths of MDF baseboard - 3 1/4", 4 1/4", 5 1/4", etc. - and if you don't like the intregal cap profile you can cut it off and route your own. 16' lengths will keep you from the added work of scarf joints on most walls.
I use BIN to seal edges when I route profiles. A water based primer will do like water in the bathroom does - cause the MDF to swell.
good call on the base, especially routing own profile.
Ralph, thanks & headsup for posts you haven't read... I'm way too stupid to get "we be jambing" up, but you were a major factiod...dang, you were THE major factoid, do I have to post more pics?<G> Don't worry, we can fix that later!
Is this the thread you are referencing?
http://forums.taunton.com/tp-breaktime/messages?msg=45716.37
Nice clean finish. I presume the homeowners are satisfied with results. How much extra expense and aggravation did you save with that method?
Now I HAVE to get that haircut. Can't fit the hat over the newly swelled head.<G>
The homeowners love it. They probably didn't save dime. The Grail Coat guy wanted to use foam for the details...probably would have been much easier, but that was nixed. Now, if the bobcat would just stop hitting the house<G>Hey, you still have hair? LOL Don't worry, we can fix that later!
i just trimmed out 24 windows with 3 1/4 inch primed mdf used power nailer no problems also price was wright 35 cents a liner foot p.s. iam not a carpenter put i shure do like the work
i also have trimmed several homes in the past couple of years with MDF.
It gives a reasonable look, and for a very reasonable price.
no problem.
For the cut edges on some mdf cab doors I just did, I used a thinned down slurry of yellow glue/water to slather on and then sand. Painter said it took paint like the face. Read about that technique here I believe.
Dust from ripping is nasty, like talcum powder. Take dust precautions, like outside with a good wind..............
Remodeling Contractor just outside the Glass City.
Quittin' Time
Personally I don't like MDF trim. Cratering is a problem, although the new Ultralight product is better on that score - but it costs same as primed pine so what the heck. I also find it difficult to get good coped joints as it is prone to tearing and fuzzy edges.
Wally
For a while I was buying 5 1/4" MDF colonial baseboard because it is the same price as 3 1/2" wood base. I figured I was giving the client a nice little up-grade at no extra expense to me.
Until..... now figure in the cost of an $80 trim blade after about 40-50 cuts with the compound miter. MDF will kill a nice blade quick. If I use MDF now I keep a specially marked blade for just that. It can be a PITA switching between blades all the time and the cost savings has gone out the window.
The same thing for my tablesaw. I will not rip MDF sheets without changing blade first.
I think MDF has its place so I use it sometimes, and yours might be one.
cons - the volcanoes if you aren't careful nailing, the edges chipping if not radiused, and the dust - but also it is very hard on tooling.
Sounds like you plan on 4x8 sheets ripped. Then you would need the plane the side cuts smooth. I wouldn't want to do that to my planer, but I don't have carbide blades in it to throw away either.
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Man, I ran some 1/4" mdf through my jointer...dang good thing it was on the outside of 12" knives...course maybe if I wanted a quarter inch rige as a detail it would cool...that stuff is mighty hard<G> Don't worry, we can fix that later!
was the jointer drunk? LOL
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One of my guiys did a house with MDF he milled himself and ruined a lot of cutters. He finally learned from someone that when milling MDF, the angle on the cutter and the feed rate is supposed to be different just to survive.
the dust, the dust, and the dust are the three main reasons I try to avoid it though
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I'd never run MDF through a jointer or planer.
I'd recommend sanding instead.
Trying to make a shooting board, sander's don't make stuff too straight!...I'd never run it through again, though<G> How else do you learn these "tricks of the trade?" ha, ha, ha, at the time it only cost a buck an inch to sharpen jointer knives...LOL Don't worry, we can fix that later!
Edited 1/5/2005 7:52 pm ET by bucksnort billy
I'm not a carpenter, but I've done the baseboards in a couple of rooms with MDF. I got pre-primed baseboard molding from Lowe's which only needed a quick wipe-down with sandpaper before painting. I cut returns for all ends, so I never encountered having to prime or paint bare MDF. I used a DW708 for most cuts and either a Delta scrollsaw or Bosch jigsaw for coping, although I'd be interested in learning techniques for coping with a router. One trick I used was to glue a piece of 220 emory paper onto a piece of the molding; coped edges were finished by sanding with this. Final non-coped cuts were made with a guillotine-style miter cutter. The dust created when cutting MDF is exceptionally fine, so I too would recommend doing all cutting outdoors, if possible. All molding was painted before installation, and was installed with a 15g pneumatic nailer. Cratering really wasn't a problem. Painter's caulk was used on all joints and nail holes, as well as between the wall and the top of the molding with good results. For painted molding, overall, I think MDF is a good choice. I can't gauge the durability of baseboard MDF yet, since I did this only a few months ago, but so far, so good.
Durability - if it gets nicked ( and it will easier than pine) repair it immediately before it can absorb moisture form the airDo not ever let it get damp or wet. It will disintegrate. Pine or poplar will only swell a bit
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