# How much polyurethane goes onto plywood



## Jaymz (Mar 3, 2010)

In the past I have used plywood for many projects, sometimes 3/4" but mostly 1/4" and 1/8". The issue I keep finding is that it takes the stain wonderfully, but when I apply the polyurethane, the plywood acts as a sponge. Any feedback on how many coats of polyurethane I have to use to get a "smooth as glass" finish? Or any ideas other than polyurethane that I should be using?


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## hObOmOnk (Feb 6, 2007)

Seal with shellac, i.e. dewaxed shellac, as your sacrificial first coat.


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## QuangFromCalgary (Mar 11, 2010)

I put 5 coats of poly on my table (not plywood), wait for a month for it to fully cure. Rub the finish with wet/dry sand paper from 600 to 1500 grit (with dish soap water as lubricant). That was how I got a smooth as glass finish. There are few other ways to "rub" the finish. You can google it.


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## Ingjr (Feb 21, 2010)

Some of it depends on what type of ply your using. The Oak veneered I buy REALLY soaks it up, while the birch I buy, not so much. Also depends on if you thin it or not. I always thin my first coat, and generally my last coat. How much in between varies, I'd say usually an average of 5 from start to finish. YMMV.


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## hazbro (Mar 19, 2010)

yeah, what these guys said. run zinsser seal coat wax free shellac, and then your urethatne. as far as the wood "soaking it up" that has to do with the grain. if you run a tight grained wood like maple you can skip the seal coat, but a porous grained wood like pine or oak will sponge it up until you've got a solid core urethane wood like panel.


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## Ger21 (Oct 29, 2009)

The other day I was coating some MDF with poyurethane. For the first coat, it'll basically soak up as much as you put on. After the first coat is dry it will start to build up. So the best thing to do is put on one quick "seal" coat.


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