# Sealer For MDF?



## gfadvm (Jan 13, 2011)

I just built a 4'x6' assembly/finishing table and am covering it with MDF. What would be best to seal it to keep glue, finish, etc from sticking to it? Thanks in advance.


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## DonnyBahama (Jun 21, 2011)

Hi, Andy! I think what most people do is top it off with a sacrificial sheet of 1/8th inch Masonite.


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## HorizontalMike (Jun 3, 2010)

Johnson's Paste Wax, cheap and works well.


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## ClintSearl (Dec 8, 2011)

Varathane waterborne poly for floors.


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## Howie (May 25, 2010)

I used poly on mine then like Mike says,Wax it.


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## Sawkerf (Dec 31, 2009)

I use water based poly - often whatever is in the can from projects. About once a year, I scrape it down and give it a fresh coat.


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## gfadvm (Jan 13, 2011)

Mike, The wax would be easiest but I was comcerned that MDF will just soak up wax like a sponge? No finish under the wax? Donnie, Glad to hear you're up right and taking air.


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## Bobsboxes (Feb 8, 2011)

Andy, I have alot of mdf counter tops in my shop and I put a couple coats of poly on it. You can hit any glue stuck to it, after it drys, with a puddy knife and it peels up. The nice thing about poly is you can scuff it up, hit it with a sander and recoat it and it looks like new. I have built several roll around tool boxes and I put a piece of 1/4" hard masonite on top, so it is easily replaced. Also coated that with poly. Then just plain old johnson floor wax.


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## lizardhead (Aug 15, 2010)

I covered mine with a clear sheet of Plexiglas, I just use a 1-1/4" chisel to remove any glue, trust me I use it a lot


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## Kentuk55 (Sep 21, 2010)

I know both water base poly, Johnsons paste wax are gr8. glue comes right off. @lizardhead: plexi? hummm sounds interesting.


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## gfadvm (Jan 13, 2011)

Thaks for all the quick input. I guess poly won the contest. Now, how many coats should I apply? I think I'll use water based as I have some that I will never use otherwise (and it should dry quicker).


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## vonhagen (Dec 5, 2011)

you could use formica and just contact cement it on and nothing will stick to it but you must use a backer on the other side so it wont warp. my main work bench is 1 3/4×6 poplar frame with 3/4 mdf with standard grade formica and i just use saw horses and level it with shims and it also works on the floor as a nice level flat surface to mock up large pieces. never use wax on your work surface as it will transfer to your wood and screw up your finish


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## gfadvm (Jan 13, 2011)

Hey Blaine, My workbench is covered with Formica and I love it but don't want to spend $50 to cover this table so Polyacrylic looks like the plan for tomorrow.


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## Kentuk55 (Sep 21, 2010)

I'd say at least 3. my $.02


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## vonhagen (Dec 5, 2011)

go poly


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## Helkat (Feb 11, 2012)

I used Spar urethane on mine, about 3 coats as is got sucked in pretty good by the mdf. At the time I was in a basement that flooded regularly, and I was concerned about it sucking up moisture and expanding over time so I did all sides.

Still holding up good for me.


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## wapakfred (Jul 29, 2011)

I'll suggest an alternative to a film finish. What I used on mine was a Blo/turp/beeswax finish. Glue (and finishes) pop right off, doesn't flake/peel, and is easily renewed. My assembly table is an MDF torsion box, and even though it's only used for assembly (and finishing) it still gets quite a bit of abuse. Read more about this here if you think t might be of interest. This article advocates this for a workbench, but it's just as applicable to an assembly table.


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## Kentuk55 (Sep 21, 2010)

very interesting Fred. thnx for the link


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## Chipy (Apr 20, 2011)

Poly or paste wax.


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## jcurcio (Mar 13, 2012)

I don't think paste wax will be very much help. I would use a high build poly if you just want to seal the mdf, but the best way would be to laminate it with formica. My assembly table is actually just 3/4" melamine. Glue scrapes right off of it, and when it gets ruined, all I have to do is flip it over. And best of all, It's cheap!


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## waho6o9 (May 6, 2011)

poly then paste wax.


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## Martyroc (Feb 1, 2012)

Minwax water based poly, dries quick and easily repaired. I have used water baseed ploys and stains recently and been pleasantly surprised. My daughter likes to spend time with me in the shop building, and to put it in her words regarding oil based stains, " daddy that stuff is Stinky"! Need less to say I was skeptical but it's been working well. Maybe I'm clouded by being able to have my daughter enjoy my hobby with me, who knows?


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## gfadvm (Jan 13, 2011)

Hey guys, It's done. I used 5 coats of Polycrylic and waiting for it to fully cure (not sure how long that is) before deciding whether to wax it or not. I don't want wax contaminating my wood or finish.


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## davidroberts (Nov 8, 2008)

shellacy by cracky


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## Loren (May 30, 2008)

MDF surfaces are very water resistant. The edges are very porous.

Pour water on a piece of MDF and it will just pool there for a long time
and may run off if the piece is not flat. I know this from leaving
pieces out in the rain. It is not like particle board in this respect. 
It does not take glue especially well without sanding. The surfaces
are treated with heat and pressure or something and are kind
of like masonite, but not so tough. Wax would, I expect, be
sufficient to make the surface glue resistant enough to pop off
dried glue with a chisel.


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