How much polyurethane goes onto plywood

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Forum topic by Jaymz posted 03-17-2010 06:57 PM 11242 views 0 times favorited 5 replies Add to Favorites Watch
View Jaymz's profile


9 posts in 3005 days

03-17-2010 06:57 PM

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?

5 replies so far

View hObOmOnk's profile


1381 posts in 4127 days

#1 posted 03-17-2010 07:08 PM

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

-- 温故知新

View QuangFromCalgary's profile


33 posts in 2998 days

#2 posted 03-17-2010 08:02 PM

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.

View Ingjr's profile


144 posts in 3016 days

#3 posted 03-17-2010 10:37 PM

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.

-- The older I get the faster I was.

View hazbro's profile


109 posts in 2990 days

#4 posted 03-20-2010 04:13 AM

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.

-- measure once, keep cuttin' til it fits

View Ger21's profile


1074 posts in 3131 days

#5 posted 03-20-2010 10:15 PM

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.

-- Gerry,

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