# What's the best way to seal MDF?



## xvimbi (Sep 29, 2009)

Besides laminating with Formica, what is the best way to seal MDF with the purpose of using it as a router tabletop? I'm in North Carolina where it gets quite humid in summer, and I only have easy access to 'normal' MDF, not any particularly moisture-resistant version. 

Thanks so much! MM


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## timbertailor (Oct 4, 2009)

xvimbi said:


> Besides laminating with Formica, what is the best way to seal MDF with the purpose of using it as a router tabletop? I'm in North Carolina where it gets quite humid in summer, and I only have easy access to 'normal' MDF, not any particularly moisture-resistant version.
> 
> Thanks so much! MM


A couple coats of paint on the open ends or polyurethane. I prefer the latter.


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## Twill57 (Jun 8, 2009)

Any wipe on oil will work. I have used shellac, poly and tung oil. MDF will drink up quite a bit.


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## garybaritone (Feb 21, 2009)

Sealing is one thing. Surface hardness is another matter. I guess I wonder why you would not wish to use Formica for your router table surface. I used a router table for 25 years with a formica top with little wear. I suspect a top of MDF only would not last as long.


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## Ghidrah (Oct 21, 2008)

Formica protects against severe dings from impacts too. 
I don't baby my tools, I'm wicked careful with heavy and or sharp objects, yet I know, (from past events) due to a small/crowded shop I'd have a number of divits in the table top without the formica.


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## xvimbi (Sep 29, 2009)

Thanks for the replies, so far.

I realize that Formica has some protective features. However, I have to get out of my way to obtain some of it. At this point, I want to get a working router table in an uncomplicated fashion and use it while I think about the next version. In addition, I was interested in that question in general, because I'd like to seal some jigs made with MDF.

Thanks again. MM


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## Bob N (Oct 12, 2004)

Hi Mischa,

I have found Poly to work well for my needs in that area. Usually I have some sitting on the shelf that is getting old so it is a good excuse to use it up before buying a fresh can


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## a1tomo (Dec 3, 2008)

I have had good luck with "Watco" oil. Any shade will do. 

Admittedly, it is not as resistant to "dings" as laminate, but is a heckuvalot cheaper. A couple coats left to properly dry, followed by an application of paste (Johnson's) wax gives a slick surface.

This method also works well for workbench tops. Any dribbles of glue or finish is easy to scrape off.

Happy Halloween!:jester:


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## BigJimAK (Mar 13, 2009)

xvimbi said:


> Besides laminating with Formica, what is the best way to seal MDF with the purpose of using it as a router tabletop? I'm in North Carolina where it gets quite humid in summer, and I only have easy access to 'normal' MDF, not any particularly moisture-resistant version.
> 
> Thanks so much! MM


You've just asked a "What company makes the best car" kind of question. 

In essence you want to control the rate of moisture absorbtion from the air. As in wood finishing where some prefer wax, some oil, some poly, here some prefer laminate, some hardwood, some wax, some poly, some shellac and others. Any will work. Some are less $$, some require more or less maintenance, and (a big) part is what looks best to you. It's *your*table.


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## drasbell (Feb 6, 2009)

Try boiled linseed oil it works great.. thats what I use,,


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## ccmnova (Nov 4, 2009)

Is there something else besides MDF to make a top from ? What about a good cabinet grade plywood -


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## anotherBob (Oct 28, 2009)

ccmnova said:


> Is there something else besides MDF to make a top from ? What about a good cabinet grade plywood -


Phenolic Faced Plywood at Woodcraft:
Phenolic Faced Plywood - Woodcraft.com

This is some really good stuff for tables and jigs... if you use it with a torsion box design, your table will be flat from corner to corner, and very solid. I made a small table recently with this stuff (3/4" matching top and bottom panels), dadoed 1/4" grooves that hold 1" thick, 2" wide half lapped/overlapping hardwood splines. The total thickness of the tabletop is right at 2 inches including formica which covers a 1/4 inch/recessed aluminum mounting plate. I would definitely do this over... been really happy with it. First choice would be a cast iron table, but this really doesn't make a bad second choice.


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## RStaron (Sep 25, 2009)

ccmnova said:


> Is there something else besides MDF to make a top from ? What about a good cabinet grade plywood -


I used a sink cutout from a counter formica counter top. It depends on how fancy you want it.


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## AxlMyk (Jun 13, 2006)

A couple thick coats of paste wax is all I use.


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## ccmnova (Nov 4, 2009)

Ok - I have an old hospital table with folding legs. The table top is some kind of 3/4 inch particle or pressed board and covered with a laminate. The size is 60 x 36 inches. When set up, this table is as solid as a rock. I was going to use it for a router table with a drop-in plate so that I could remove it when i want to fold the table and put it away. The laminate top is a little warped however and I tried to re-glue it but it's still wavy. The steel frame and folding legs of the table comes off and could be mounted to a piece of 3/4 inch MDF and then I could put some laminate on top. The size is great and the fact that it folds out of the way is also a plus. I am just concerned that the table with teh 3/4 inch MDF would not be flat - should I use 3/4 inch cabinet grade plywood ?


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## timbertailor (Oct 4, 2009)

ccmnova said:


> Ok - I have an old hospital table with folding legs. The table top is some kind of 3/4 inch particle or pressed board and covered with a laminate. The size is 60 x 36 inches. When set up, this table is as solid as a rock. I was going to use it for a router table with a drop-in plate so that I could remove it when i want to fold the table and put it away. The laminate top is a little warped however and I tried to re-glue it but it's still wavy. The steel frame and folding legs of the table comes off and could be mounted to a piece of 3/4 inch MDF and then I could put some laminate on top. The size is great and the fact that it folds out of the way is also a plus. I am just concerned that the table with teh 3/4 inch MDF would not be flat - should I use 3/4 inch cabinet grade plywood ?


I would not be sure of the stability of plywood over time although it would be better than a solid wood.

I would recommend buying a sheet or two of melamine from the home center and doubling them up for a 1 1/2" thick surface. Most of the better tables you see on the market are built this way. If you have skills, doubling up some MDF and laminating, if you desire, is also a good option. A good solid base/frame to support the top is still a strong recommendation as routers and their accessories tend to cause sagging in less properly supported solutions.

It would be nice to just fold it up and put the table away but not a long term solution I would recommend.

Good luck and let us know what you decide to do. Extra points for photos!!!:dance3:


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## mikeos1944 (Nov 6, 2009)

timbertailor said:


> A couple coats of paint on the open ends or polyurethane. I prefer the latter.


I use 1 part polybond ( Resin W) to 5 parts water to seal MDF before painting.


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## ccmnova (Nov 4, 2009)

I could use a 3/4 inch mdf and then find a 3/8 thick sheet of mdf that would be the same thickness as the router plate to laminate on top the 3/4 inch - would sure make the plate mounting easy !!


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## BigJimAK (Mar 13, 2009)

ccmnova said:


> Ok - I have an old hospital table with folding legs. The table top is some kind of 3/4 inch particle or pressed board and covered with a laminate. The size is 60 x 36 inches. When set up, this table is as solid as a rock. I was going to use it for a router table with a drop-in plate so that I could remove it when i want to fold the table and put it away. The laminate top is a little warped however and I tried to re-glue it but it's still wavy. The steel frame and folding legs of the table comes off and could be mounted to a piece of 3/4 inch MDF and then I could put some laminate on top. The size is great and the fact that it folds out of the way is also a plus. I am just concerned that the table with teh 3/4 inch MDF would not be flat - should I use 3/4 inch cabinet grade plywood ?


Henry... I went through the same "what do I use for a top" issues that you are in. My top is 32x52, just about the same size. I asked a lot of questions here and the general consensus here made MDF my material of choice. Here's what I was told: If there's one thing MDF is, it's flat. Because it has no grain, it has no tendency to warp due to internal stresses. Like any wood product, all exposed surfaces should be sealed to reduce the rate of change of moisture content within it. It was recommended to laminate 2 pieces of 3/4" MDF, covering both surfaces with Formica. Other laminate will work but $$$ aside, Formica wears better than melamine. The edges whould be sealed also, whether with a finish (poly, shellac, paste wax, etc.). I followed this advice. 

My mileage? I haven't had the table a long time yet (I made it about 5 months ago) but: It has two 3-hp (15A) routers in it (plus fences, etc.), has been supported solely by 2 sawhorses, and is dead-gnats flat. It is rock-solid and I'd have no compunction standing on it (if I had a reason to) and I'm a big ol' guy. The MDF does a great job of damping any vibration. The down side is its heavy. 

I'll leave it to others to comment on how a 3/4" piece would work. As for me, I'd be a bit leary (even with plywood) since my router lift plate is 3/8" thick, so the routed ledge holding the "tank" would only be 3/8" thick.

Just my $0.02...


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## Mike Gager (Jan 14, 2009)

shellac and wax worked well on mine


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## Echonav (Sep 17, 2009)

I know this is an old thread bet here are my comments... I use a few coats of Watco Danish Oil on my MDF worktable top. It dries pretty hard. I live in the Pacific Northwest and have had no problems. When the top starts looking a bit worn, I sand it and apply a new coat of Watco Oil and it looks like new....


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## Mt-Pockets (Sep 9, 2009)

After filling all of my Counter sunk/ predrilled holes.. With "Durhams water putty"

I'll either run a smooth coat of Putty or drywall compound along the routered edges.. and sand in between ...

Then Apply an "Oil based Primer" sanding between coats.. then apply finish coats of either Lacquer or latex depending on the project...

But ya must sand in between coats.. to make it Nice-Nice..


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