# Final Coat of Polyurethane



## tommyc325 (Sep 8, 2014)

Hi Everyone

I about 4 hours ago I applied my third coat of polyurethane to a walnut table top I made. After each coat I sanded down and vacuumed with 220 grit. Now that my third coat is dry I noticed there's some air bubbles and some ruff spots that I would normally sand down but I wasn't sure if I should sand this final coat.

My question to you is what do you suggest I can do for this final coat to get this table super smooth and keep the look that it has.

Thank You In Advanced.

Tom


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## Woodchuck2010 (Jan 19, 2016)

I'd say the final coat is the last one you apply. Sand it and apply another coat if you're not happy with the finish.


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## conifur (Apr 1, 2015)

Well gives a hint, what are you using for a finish, oil, or water base?? How are you applying it???
Another freaking post, I want answers but not enough info!!! My Rant
Vacuumed, you should have wiped it down with a damp cloth with many different things, water, mineral sperits, Naphtha, ect.


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## tommyc325 (Sep 8, 2014)

Fast Drying Semi Gloss Poly Oil
Foam Roller


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## conifur (Apr 1, 2015)

I never used it or applied that way, I bet the the combo is putting air bubbles in it and b4 they can air out, the Poly sets up. I would lightly sand them out, then use the Poly and cut it with Mineral Spirits, 50/50 and wipe it on for your final coat.


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## conifur (Apr 1, 2015)

Also never shake a can of finish to mix, stir it, shaking puts air bubbles in it.


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## tommyc325 (Sep 8, 2014)

> Also never shake a can of finish to mix, stir it, shaking puts air bubbles in it.
> 
> - conifur


I didnt shake the can


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## WhoMe (Jul 9, 2009)

I usually avoid foam rollers, brushes, they have a tendency to make bubbles. That has been my experience. And the fast drying poly might be drying too fast for the finish to flow out and may trap any bubbles. 
If you can sand out the bubbles do that and if you can thin the last coat, that may help prevent any possible bubbles that the foam roller may cause. Also, I usually sand with 320 on the last couple coats. 
Just some suggestions.


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## BurlyBob (Mar 13, 2012)

Let it dry hard, real hard. Give it a light sanding with 600 grit wet dry paper. Thin the poly down super thin. Get a piece of polyester cloth and fold so you get a 3-4 inch fold. Dip in the thin poly and use the fold as a squeegee to move the poly along the table top. If you can look across the top from the side you can see where you need to apply the varnish to give it complete coverage.

I've used this method for years and have been able to achieve extremely smooth finishes. I've also put the fold inside a piece of pantyhose to prevent lint in the finish.

Best of luck.


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## RogerM (Oct 31, 2011)

Your poly is too thick. Dilute with an equal part of mineral spirits and put on another coat.


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## distrbd (Sep 14, 2011)

> Get a piece of polyester cloth and fold so you get a 3-4 inch fold. Dip in the thin poly and use the fold as a squeegee to move the poly along the table top.
> 
> - BurlyBob


Never tried it that way,thanks burlyBob.


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## Hazspec (Feb 22, 2008)

Lightly sprinkle water on finish and lightly sand with 440 grit; wipe dry with damp cloth; apply a light brush finish of poly urethane and immediately go over with brush application with sponge.


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## pintodeluxe (Sep 12, 2010)

I agree with others to wet sand once fully cured. I use a spray bottle of tap water and a 1500 grit soft sanding sponge.

Applying poly with a roller would be the cause of the problem.

Hope it comes out okay.


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