Replies

1. 
   loucarabasi | Feb 26, 2006 02:38pm | #1

   Tom, I run alot of mdf trim with my shaper, I also have a williams and hussey molder to run with. If you use a good lacquer sealer primer (ML Cambell) Hammer it with a heavy coat and then sand, You will achieve the best result. If you use a water based primer you will keep raising the surface grain. It may require 2 coats. The stuff dries fast and is easy to work with.

   Hope this helps you, LOU

2. 
   Jer | Feb 26, 2006 03:56pm | #2

   I made all the casing in my house from MDF and it's fine. It's a different animal than wood that's for sure. Just make sure you have dust collection on your shaper and saw because it produces tons of fine dust. It's also hard on blades of any sort.
   I sealed mine with a quality oil primer, then sanded lightly before painting. The nice thing about MDF is that it's cheap, and once in place, it stays there and doesn't have seasonal movement.

3. 
   basswood | Feb 27, 2006 12:14am | #3

   For molding, try a premium MDF. Typical MDF has high quality material on the surface so the milling exposed coarser material that requires extra coats of priming & painting and more sanding to look smooth.

   The premium stuff, mills and finishes better (though top and bottom surfaces are still smoother than milled surfaces).

   Here is a link:

   http://www.temple.com/mdf/ultrapremium.html

   For simple 1x style casing and base, the regular stuff is fine...just prime your cut or routered edges twice and sand more. For base, order 4x12 sheets (if you want to minimize joints in the middle of runs).

1. 
   user-87095 | Feb 27, 2006 01:03am | #4

   My main concern is how to deal with shaped edges. I have used MDF for painted shelves and have never been able to get the edges as smooth as the flat surfaces. The better quality primer is a good tip,I'll try. Is the lacquer stuff someone mentioned brushible,or spray only? As for higher quality MDF what should I ask for?

1. 
   basswood | Feb 27, 2006 02:06am | #5

   Just ask your yard if their supplier can get you premium quality MDF for milling...if you don't need much, you may pay extra for shipping, unless you can wait for it to go out with the next regular shipment.Check the link I gave:http://www.temple.com/mdf/ultrapremium.htmlThey probably have a vendor in most areas.

1. 
   DougU | Feb 27, 2006 05:37am | #9

   bw

   I looked on that site, man you can get sheets 5' wide by 16' long!

   I'd hate to have to move that stuff around, better get a small crane in the shop.

   Doug

1. 
   basswood | Feb 27, 2006 04:40pm | #15

   Whimp...those sheets only weigh 3 or 4 hundred pounds each.That just means you neeed a helper if you want to carry 2 sheets at a time ; > )

2. 
   Piffin | Mar 01, 2006 02:54am | #23

   He'd have to carry two ata time to keep ballasted from the wind those would catch!I come down in favour of real wood - poplar. MDF is fine for shelves 

    

   Welcome to the Taunton University of Knowledge FHB Campus at Breaktime. where ... Excellence is its own reward!

3. 
   DougU | Mar 01, 2006 06:21am | #24

   That just means you neeed a helper if you want to carry 2 sheets at a time

   I'd need two helpers, one at each end and myself to tell them where to set it down.

4. 
   Nuke | Mar 01, 2006 04:32pm | #25

   I'm curious to know what the longest piece of crown (or pseudo-crown) molding you folks have installed.

5. 
   jeffwoodwork | Mar 03, 2006 03:22am | #26

   Longest continuous piece, was just over 15' like 15'3" from a 16' MDF.  By myself that's a like trying to get a wet noodle to stay on the wall.

   Jeff

2. 
   jeffwoodwork | Feb 27, 2006 05:09am | #7

   I have used regular white Elmer's glue thinned down to about 50% with water.  Brush this mix on the milled edges then sand, seals nicely and get the finish smooth.

   Jeff

3. 
   seb | Feb 27, 2006 05:29am | #8

   there was an article in FWW or FHB about sealing the machined edges with drywall mud...then sanding...Look in index on the webpage...I used it on a couple frame and panel doors with the frames out of mdf...worked fine.
   Bud

1. 
   BryanSayer | Feb 27, 2006 06:27am | #10

   Does drywall mud not have the same problem of introducing moisture that water based primer has?

1. 
   seb | Feb 27, 2006 06:01pm | #17

   <Does drywall mud not have the same problem of introducing moisture that water based primer has?

   It allows you to fill the roughness,sand lightly, then you oil base prime it.If you want will look up the article, and get more specific..
   Bud

2. 
   BryanSayer | Feb 28, 2006 05:08am | #19

   No need to look up the article. All my trim has to be milled to match the existing stuff. I was just curious.

2. 
   kayaker | Feb 27, 2006 06:41am | #11

   Maybe fine for casing, this is Fine home building.... anyway I had to trim a house where the homeowner saved 400$ by going to mdf trim none of the door came pre-cased on the hinge side because of this.  So we started to case them and when we lifted the door off of the saw horses the casing ripped off in our hands.. not good for anything structural.... from my experence not good   just my 2cents.

1. 
   basswood | Feb 27, 2006 07:40am | #12

   For paint-grade trim, I much prefer poplar or basswood over mdf. I think MDF has its' place. It is a good choice for crown (out of harms' way), for painted bookcases (faced in poplar), and for 1x4 casing and 1x6 base (routed with a round over, or back banded in poplar).Here is a pic of a victorian reclaimation using a modern mdf base as casing with basswood banding.Cheers

   
4. 
   cliffy | Feb 27, 2006 04:53am | #6

   Buy a few extra boxes of kleenex, you will be blowing your nose alot!

   Have a good day

   Cliffy

5. 
   reinvent | Feb 27, 2006 07:58am | #13

   I have to agree with basswood's previous comment abought preferring poplar or basswood. One trade name for the 'premium MDF is 'Panfiber' It is supposed to have a core consistent with the surface. Whatever you do don't use steel knives to mill it. MDF will dull them faster than you can belive. Carbide cutters are a MUST.

1. 
   Nuke | Feb 27, 2006 03:51pm | #14

   When milling your own trim, is it typically considered a bad thing to use finger-jointed wood than MDF? I know MDF is a very stable product, but from friends that make speakers their #1 complaint is how tough it is to cut & mill, and the dust problems therein.

   I ask about finger-jointed alternatives since typically you would be covering the MDF trim with something opaque or something you cannot see through at all, thus the finger-joints would be hidden. Just curious.

1. 
   basswood | Feb 27, 2006 04:43pm | #16

   Here I can get poplar from a local mill for about the same as than finger jointed pine...so that is a good way to go.

2. 
   reinvent | Feb 28, 2006 03:09am | #18

   I would'nt use either MDF or finger jointed stock for millwork. The money saved on that material expense will more than be eaten up by the extra labor of trying to finish it nice. Poplar, basswood, and alder are all good interior paint grade woods that are relatively inexpensive. Basswood is a bit soft but if it is not gona see a lot of wear and tear than it's fine.hehe spellcheck thought I misspelled gona and it should be spelled 'gonad'

1. 
   jeffwoodwork | Mar 01, 2006 12:28am | #20

   hehe spellcheck thought I misspelled gona and it should be spelled 'gonad'

   Well that's not really a word, not in the english language.

1. 
   JMadson | Mar 01, 2006 12:45am | #21

   It's in the Random House Dictionary.

6. 
   user-75913 | Mar 01, 2006 02:45am | #22

   sanding sealer either oil or laquer based will seal the "end grain" sand  then apply an alklyd primer.

   your finish will be smooth.  MDF doesnt require any more prep then other paint grade trim.   Poplar on the other-hand is a pain unless its pre-primed since poplar is a fuzzy wood.