mdf wood

efmaron · Post by **efmaron** » Thu Jul 22, 2010 9:46 am

I have used MDF for my RAS table and router table then sealed them with boiled linseed oil and they have held up well in my non air conditioned shop here in humid Florida.

dusty · Post by **dusty** » Thu Jul 22, 2010 9:49 am

efmaron wrote:I have used MDF for my RAS table and router table then sealed them with boiled linseed oil and they have held up well in my non air conditioned shop here in humid Florida.

Sealing the material (MDF) is one of the secrets to using MDF successfully. It draws in moisture even from the air and will eventually show signs of that intrusion. Seal it well and that weakness is greatly diminished if not eliminated. For painted surfaces, where the grain means nothing visually, MDF is great.

Screw holding characteristics is a subject of another long discussion.

Ron309753 · Post by **Ron309753** » Thu Jul 22, 2010 4:04 pm

owenbrent wrote:The MDF in the photo's above were stained with an outdoor stain and then coated with urethane.

Owen,

Tell us more about the finishing process. What stain and what urethane did you use?

Your finished product looks fantastic!

Sincerely,

Ron309753

owenbrent · Post by **owenbrent** » Fri Jul 23, 2010 7:23 am

Ron309753 wrote:Owen,

Tell us more about the finishing process. What stain and what urethane did you use?

Your finished product looks fantastic!

Sincerely,

Ron309753

It's been too long for me to remember the exact stain I used. All I can remember is that it was a outdoor deck stain and that it was used more like a paint than a stain. I had to use several coats to make it look even. Using a brush instead of a roller made the finish look more like painted wood. I then coated the stain with a polyurethane with a satin finish. I would not do it this way again, because a good paint could have worked just as well with less steps.

After the first coat of stain, the edges have to be sanded in order to obtain a smooth finish. Some of the fibers stand up and make it rough. You should also sand after priming if you are going to paint the material.

barsymes · Post by **barsymes** » Tue Jul 27, 2010 12:24 pm

A few things about MDF both positive and negative.

Machines beautifully, but really hard on blades and router bits.

If you plan on painting MDF, just know that it seems to drink paint like crazy. One way I've found to get around this is to mix a 50:50 mixture of carpenter's or Elmer's glue and water and paint a thin even layer over the piece of MDF and allowing to dry before attempting to paint. Trust me, you will use a lot less paint and also provides additional sealant to prevent moisture uptake and swelling.

This stuff is great for absorbing vibrations and is super flat.

Not sure if this stuff is water proof like the above poster said though.

JPG · Post by **JPG** » Tue Jul 27, 2010 1:05 pm

Anybody tried sealing it with shellac? With or without subsequent painting?

tdubnik · Post by **tdubnik** » Tue Jul 27, 2010 2:18 pm

JPG40504 wrote:Anybody tried sealing it with shellac? With or without subsequent painting?

I have done that with pretty good success. I used this method on some of my shop cabinets. I used Krylon rattle can paint and it would take several cans even on a small cabinet. The shellac cut it down by a couple of coats and gave me a better finish expecially on the edges.

I used about 3 coats of shellac and then sanded lightly before painting.

JPG · Post by **JPG** » Tue Jul 27, 2010 2:45 pm

tdubnik wrote:I have done that with pretty good success. I used this method on some of my shop cabinets. I used Krylon rattle can paint and it would take several cans even on a small cabinet. The shellac cut it down by a couple of coats and gave me a better finish expecially on the edges.

I used about 3 coats of shellac and then sanded lightly before painting.

So you traded 'a couple of coats of paint' for 'about three coats of shellac'?

Saved time due to the shellac drying faster?

BTW Those cabinets do look fantastic!

easterngray · Post by **easterngray** » Tue Jul 27, 2010 2:57 pm

Funny this thread should appear as I was cutting bevels on some MDF this morning and had a devil of a time. I started with a sharp blade and ended up with a VERY dull blade. In spite of slow feed rate, the SS (3/4hp) didn't like the MDF one bit. It was straining to be sure. Yesterday I beveled (raised panels) some pine with the same blade and had excellent results from the SS. This is the only panel I'm making with MDF and I am glad that it's done! I was longing for a PowerPro - or at least a 1 1/8 HP motor! Alec

tdubnik · Post by **tdubnik** » Tue Jul 27, 2010 3:13 pm

JPG40504 wrote:So you traded 'a couple of coats of paint' for 'about three coats of shellac'?

Saved time due to the shellac drying faster?

BTW Those cabinets do look fantastic!

Pretty much it, except that I also got a better finish and the shellac is cheaper even at three coats.