Finishing MDF for the shop

[Porter Bassett]

I'm (finally!) setting up an outfeed table for my tablesaw. It's pretty plain Jane, and it's top is 3/4 MDF, because that's what I happen to have. I know that it's not the most durable top in the world, but it will have to do for now.

However, I can put a finish on it so that it will be slipperyer and so that glue won't stick to it.

What's your recommendation for how to finish it? Will paste wax work fine on it, or do I need to prepare it somehow before I do that?

[glenn bradley]

Shellac and Johnson's Paste Wax work for me. This isn't a work top but it may help: http://www.sawmillcreek.org/showthread.php?t=65591 or this, which is a work top. No problems with glue sticking: http://www.sawmillcreek.org/showthread.php?t=82140 I've re-waxed it about 3 times this year just as routine maintenance, not due to a problem.

[Bill Huber]

Just about anything, I used Poly on my sled and then waxed the bottom and it is nice and slick.
I even have a small work table that I used MDF on and I just waxed it good and it is still doing good and the glue will not stick.

[Jack Wilson50]

+1 for the wax. That what I used on my outfeed table.

[Joe Chritz]

I just soak it in BLO then wax. The BLO turns MDF into a cool dark brown. That and the wax it is plenty slick. I have an assembly table and an outfeed table that are made that way and I do glue ups on them regularly. The nibs just pop right off.

Joe

[Porter Bassett]

BLO? What is that?

[Rick Fisher]

I have an MDF top on mine and I coated it with Watco about 4-5 times. Eventually the finish wouldnt dry, which meant it was totally saturated. I wiped off the residue after still being wet overnight.

Glue doesnt stick to it well. Any glue blob's just pop off with a scraper.

Its actually a very durable surface. Hard and flat. Best part is that its MDF. If it gets trashed, another layer of MFD will make it new again..

[Jason Whitaker]

BLO? What is that?


B (boiled) L (linseed) O (oil)

[Art Moore]

3 or 4 coats of wipe-on poly, followed by Johnson's paste wax. Works well, and is durable.

[Lee Koepke]

another vote for BLO and wax.

It looks great and its pretty slick ( sometimes too slick !! )

I also just wiped the BLO on the maple edge trim, that too looks nice.

[Jim Becker]

BLO and wax is what I use.

[Frank Drew]

Porter,

Sealing the edges is important with MDF in order to lessen moisture uptake.

[Porter Bassett]

What do you use to seal it? I have some pre-stain wood conditioner, which is says "seals soft wood for even color". Is that the stuff I should use?

Also, MDF doesn't have any grain. Why is it important to seal the edges and not the face?

[Frank Drew]

Porter,

I meant that whatever finish you choose should also be applied to the edges, but probably twice as much since the edge of MDF (like the end grain of solid wood) is much more absorbent than the face.

Personally, I'd just use a film finish like poly or varnish, or even shellac, skipping the linseed oil, which I find slow drying and kind of smelly (think high school art class). Others like it, though.

[Tom Esh]

MDF should be sealed from humidity to stabilize it (and it will soak up a lot of whatever you use). I always use shellac - dries fast and it's cheap. Then I like to topcoat it with poly, but wax is OK too. A more expensive alternative is to laminate (Formica) both sides and seal or band the edges. Looks great, low friction, durable, and almost nothing sticks to it.

[Pat Germain]

The big advantage of BLO is it's cheap. Since paste wax is also cheap, these two finishes are ideal for workshop surfaces since they are aslo quite effective.

Although you have it on-hand, I wouldn't bother with the wood conditioner stuff. You can pick up a large can of BLO at any big box store. Just follow the manufacturer precautions about disposing of any rags or brushes after use. Yeah, BLO is smelly while it's drying. But after a few days, the smell is gone.

[Sonny Edmonds]

The best finish I have found for shop "furniture" has been oil based Polyurethane, followed by Johnson's Paste Wax.
And put the poly on all surfaces. Top, bottom, sides, ends. Seal the piece all the way around, them wax to surface that will have work slid over it or uses as a work surface.
The poly will penetrate deeply and harden the board when cured. The wax will slick it up and help keep glue, pitch, and other common contaminants from adhering to your table, or anything you make for your shop.
I also use MDF (1/2") for my TS zero clearance inserts, but with wax only rubbed into them.
MDF is great stuff in the shop for test cuts and all sorts of things, as long as you have good dust collection to contain it. :)

[Jim Kountz]

Another vote for the poly, I wouldnt fool around with BLO and waiting for it to cure, just put a couple three coats of quick drying poly and be done with it. My workbench is done this way and its help up nicely. And it does get abused sometimes too!!

[Phil Phelps]

..with your local builders supply and see if they have any damaged laminated plastic, (Formica), they would be willing to give a good deal on.

[Frank Drew]

I agree with Tom and Phil on the advantages of plastic laminate; the stuff is very smooth and very long wearing.

[Scott Schwake]

Do you guys sand the MDF before you finish it?

[dan sherman]

check out the top for my Thein's dust collector.[/URL]
[url]http://www.dans-hobbies.com/wp-content/uploads/2008/07/riser.jpg (http://www.cgallery.com/jpthien/cy.htm)

I finished it in the following manner:
1. sanded with 220
2. 2 coats of 50/50 BLO/MS
3. 6 coats of 50/50 spar urethane, & MS (light sanding with 320 after every two coats)
4. buffed with Johnson's paste wax

[Norman Hitt]

Do you guys sand the MDF before you finish it?

NOT on the FACES, and only if absolutely necessary on the edges, (if I haven't capped the edges with solid wood).

[Jerome Hanby]

Ditto, I always shellac MDF, and Johnsons goes on anything that has wood sliding across it.


Shellac and Johnson's Paste Wax work for me. This isn't a work top but it may help: http://www.sawmillcreek.org/showthread.php?t=65591 or this, which is a work top. No problems with glue sticking: http://www.sawmillcreek.org/showthread.php?t=82140 I've re-waxed it about 3 times this year just as routine maintenance, not due to a problem.

[Jerome Hanby]

Do you guys sand the MDF before you finish it?

Only if I've dropped it or done something else to damage it. I might sand the edges to clean up saw marks...

[Prashun Patel]

Dude, if yr main motivation is functional, then use whatever finish you have left over! I've shellacked, painted, varnished, oiled, and waxed MDF and hardboard. They all work very well. Outfeed tables are the perfect application for 'left over' finish, IMHO!!!!