# How do I apply polyurethane to 120 year old rough wood?



## Lmhall (Apr 3, 2014)

*How do I finish raw 120 year old rough wood?*

I have acquired 120 year old barn wood panels that will be re-purposed into a coffee table. 
I have cut the boards to length, and have laid them out for assembly... However, prior to putting this thing together, I want to make sure I can polyurethane the top. It has lead based paint (red). I have taken the proper precaution when scraping and cutting the boards, this is not posted for a lead based paint removal discussion... I just want to know: Can I poly this wood, which is very rough and weathered, without sanding the panels prior? I don't mind doing a bunch of coats, and with enough clear, I am confident that the lead paint would be sealed on. I may wire brush it? But I want to keep the natural patina and worn look, along with the red paint. 

Anyone on suggestions with polyurethane on rough (very rough) cut wood, let me know. Any help is much appreciated!


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## Gary Beasley (Jan 21, 2009)

No wire brush, that will put lead paint dust into the air. Maybe clean the dirt off with a paint brush then flood coat the wood till it stops absorbing the polyurethane. After all that cures you may be able to buff it down to a softer texture without penetrating to the lead paint.


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## Lmhall (Apr 3, 2014)

How do you flood coat the poly? Is there a particular method, or is it simply just coat after coat?

I wanted to do thin coats to help it's longevity... But I have heard that just pouring on poly, like an epoxy, would be my best bet. That just doesn't sound right at all though??

Thanks again


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## mmwood_1 (Oct 24, 2007)

I can tell you a couple of things. First, yes you can poly over that stuff. One issue though is that you really need to lightly sand poly between coats for good adhesion. This may be difficult with a rough surface. Could try scuffing it with steel wool.

Second, I would thin the initial poly coat about 10% with mineral spirits. This may help with bonding to the surface of the piece.

Otherwise, you CAN use a pour-on clear finish. It's basically clear, 2 part epoxy. You would need to provide temporary sides to keep the stuff from running off the edges. For that, you could make a frame of 1 x 2 to fit snugly around the perimeter, putting waxed paper between that frame and your table top so they don't bond. It would be a single coat pour, thick,which would be self-leveling and give you a flat, smooth surface, if that's what you want. It's also called decoupage finish.

If you try pouring on poly in this manner, you may have significant drying issues. Epoxy hardens due to chemical reaction, so the thickness is not a problem for it. Poly dries with exposure to air so you may have issues of shrinkage and cracking in the drying process if you pour a thick coat.

Whatever you do, try hard to remove as much dust as possible from the surface before applying a finish or the dust may inhibit bonding. Good luck.


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## Brian T. (Dec 19, 2012)

Another finish would be clear, methyl methacrylate resin used in fiberglas boat construction.
That, you can "flood-coat" a table top with a masking tape dam around the edge.
This is the one and the same thing as Plexiglas. You get to call the shots = how much catalyst
for the temperature and working time that you need.


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## punkin611 (Sep 17, 2013)

Lmhall said:


> I have acquired 120 year old barn wood panels that will be re-purposed into a coffee table.
> I have cut the boards to length, and have laid them out for assembly... However, prior to putting this thing together, I want to make sure I can polyurethane the top. It has lead based paint (red). I have taken the proper precaution when scraping and cutting the boards, this is not posted for a lead based paint removal discussion... I just want to know: Can I poly this wood, which is very rough and weathered, without sanding the panels prior? I don't mind doing a bunch of coats, and with enough clear, I am confident that the lead paint would be sealed on. I may wire brush it? But I want to keep the natural patina and worn look, along with the red paint.
> 
> Anyone on suggestions with polyurethane on rough (very rough) cut wood, let me know. Any help is much appreciated!


You might pressure wash it first. Let it dry real good. I would then topcoat it with dewaxed shellac. then test steelwood 0#-00# on it to somewhat "smooth" it down. You will never regret undercoating varnish with dewaxed shellac. If you ever decide to strip it you will thank your lucky stars you did. (or whoever does in the future after your long gone) :laughing:


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## cabinetman (Jul 5, 2007)

I would just dust brush it lightly with a bristle paint brush. You could just brush on the poly or spray it on in thin applications. I wouldn't pour it on.








 







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