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sealing the edge of a MDF disc

sealing the edge of a MDF disc (post #169261)

booker16 on Wed, 10/26/2011 - 08:57 (updated 10/26/11 - 10:34)

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I'm building a panel saw and the disc in which the saw sets is rabbeted and mates to the traveling base. I want to use MDF and need to seal the edge grain in such a way that it can be waxed or lubricated somehow to enable the disc to spin with little effort and wear.

Thanks for any suggestions

Bill

While you are waiting for (post #169261, reply #1 of 7)

by swenson in reply to booker16 [original] on Thu, 10/27/2011 - 04:01

While you are waiting for someone who knows more than I do about MDF to answer I have to question the term edge grain when it comes to MDF. I don't think MDF has any grain. Perhaps you mean just the edge of the MDF?

Is the base made of MDF too?

Would just sanding it to say 400 grit and just waxing it work?

WARNING: My 2 cents worth may only be worth 1 cent.

MDF sealer (post #169261, reply #2 of 7)

by RalphBarker in reply to booker16 [original] on Thu, 10/27/2011 - 09:27

My suggestion would be shellac, made from flakes, so you can control the mix. I like to use a one-pound "cut" (a ratio of 1 pound of flakes to a gallon of denatured alcohol, usually mixed in smaller batches, though). The first couple of coats will absorb into the material almost entirely, and the third or fourth coat will start to build a finish. It is quick to apply, and is one of the most moisture-resistant finishes around. A light sanding with 220-grit after the second application will help get rid of stray fibers and hasten the creation of a smooth surface that can be subsequently waxed (finishing wax or Johnson's Paste Wax).

Actual wear resistance will still be a function of the strength of the MDF, however. One shouldn't expect miracles from MDF.

MDF edge (post #169261, reply #3 of 7)

by booker16 in reply to booker16 [original] on Thu, 10/27/2011 - 13:45

The shellac won't make the MDF swell will it?

swelling (post #169261, reply #4 of 7)

by RalphBarker in reply to booker16 [original] on Sun, 10/30/2011 - 08:06

I haven't noticed any swelling from applying shellac to MDF.

I've used wood glue (mixed w/ (post #169261, reply #5 of 7)

by murraytulloch in reply to RalphBarker [original] on Mon, 11/07/2011 - 10:41

I've used wood glue (mixed w/ a bit of water - I think) as a sealer before, but that was prior to painting. I think shellac is the most common remedy. I've used it on a sacraficial tablesaw fence and it worked nicely.

mdf and friction (post #169261, reply #6 of 7)

by bones in reply to booker16 [original] on Mon, 11/07/2011 - 11:51

While MDF is a great inexpensive material If friction is involved it will not cut it. Over time it will wear I don't care how you seal it. I would use another material. I built my Router table top out of mdf over 7 years ago and for the miter guage slot, I inlaid a piece of aluminum chanel. I knew if it were mdf over time it would wear and get sloppy. I'd think the same would happen. aluminum, plastic, or some other sturdier material is advised.

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