How to avoid brush marks in polyurethane?

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Forum topic by bues0022 posted 12-26-2010 05:21 AM 35525 views 1 time favorited 13 replies Add to Favorites Watch
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249 posts in 3156 days

12-26-2010 05:21 AM

Topic tags/keywords: finishing

I’m having a rough time with my finish. I put 5 coats of urethane on a Christmas present coffee table. The wood has some curl and wavy grain patterns. I keep getting brush marks and don’t know how to avoid them. I’m using a foam brush. Should I use a rag and rub it on? Thin the top coat slightly with mineral spirits before applying? (yes I am sanding between coats) I need to complete this tomorrow morning. Any tips?

-- Ryan -- Bristow, VA

13 replies so far

View SouthpawCA's profile


270 posts in 3229 days

#1 posted 12-26-2010 05:31 AM

This might help … I use this method all the time.

-- Don

View Todd A. Clippinger's profile

Todd A. Clippinger

8901 posts in 4096 days

#2 posted 12-26-2010 05:35 AM

I prefer to use a wipe-on poly because it goes on thinner and does not leave the brush marks.

You could sand what you have to smooth it, then thin the poly about 50% and use it as a wipe-on. Using it as a wipe-on applies it in a thinner layer and with it thinner it will also dry faster.

Otherwise I use a good brush for applying (I prefer a china bristle) to lay out a smooth coat. The problem still may remain though so once again I default to the wipe-on. Also the thicker brush applied coat will take longer to dry.

Good luck meeting your deadline, you are at the mercy of your product and it’s drying time. Do not change product though and do not push it or you will muck it up. I have learned this lesson the hard way.

-- Todd A. Clippinger, Montana,

View Bill Davis's profile

Bill Davis

226 posts in 3920 days

#3 posted 12-26-2010 05:48 AM

With 5 coats of poly built up you might try wet sanding it to remove those pesky marks.

View John Ormsby's profile

John Ormsby

1285 posts in 3733 days

#4 posted 12-26-2010 06:08 AM

I mostly spray the last coat of poly if using normal poly. I also use wipe-on poly as Todd does.

I also use these pads to apply poly. They will work for the finish coat also.

You can also thin the poly a bit so it will flow better. Keep an eye out for runs.

-- Oldworld, Fair Oaks, Ca

View Steven H's profile

Steven H

1117 posts in 3056 days

#5 posted 12-26-2010 07:03 AM

Get rid of the foam brush, it is crap. You can either thin it down to 50% to Wipe On or buy a high quality brush.

View Todd A. Clippinger's profile

Todd A. Clippinger

8901 posts in 4096 days

#6 posted 12-26-2010 07:15 AM

I think John Ormsby brings up a good point on the pad. I have used store bought pad applicators with good success.

Most often I use a blue paper shop towel folded into a nice pad for application. It is simple and it works quite well.

-- Todd A. Clippinger, Montana,

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John Ormsby

1285 posts in 3733 days

#7 posted 12-26-2010 08:26 AM

I realized I forgot to add the link to the type of pads I use.

I cut these into 1/4, 1/3, or 1/2 the size at times so as to conserve pads when coating smaller things. A hack saw with a fine tooth blade cuts quickly. Make sure to put on masking tape on the cut ends to lock the styrofoam beads in place. Otherwise they will get into the finish.

-- Oldworld, Fair Oaks, Ca

View Todd A. Clippinger's profile

Todd A. Clippinger

8901 posts in 4096 days

#8 posted 12-26-2010 06:50 PM

So now we are into the next day.

Did you get it figured out? Let us know.

-- Todd A. Clippinger, Montana,

View bues0022's profile


249 posts in 3156 days

#9 posted 12-27-2010 05:58 PM

Sorry for not posting back. It was a busy day yesterday finishing this project, driving home, starting another that needs to be wrapped today….

This is what I did with the extremely limited supplies (was at my inlaws and not near my own equipment/supplies):

Sanded down the top with some fine grit I found in the basement (it said 4000 on the back, but it felt more like 400) Then I diluted my poly down about 50/50 with mineral spirits, and applied with a small chunk of cloth. The results turned out not 100% perfect, but the imperfections are only ones that I notice because I’m picky and I made it. When I pointed the imperfections out to my wife, she couldn’t tell, so I know my mother-in-law (gift recipient) won’t notice either.

This salvage turned out good, but I definitely need to do some more research on finishing fur future projects. I know very little besides how to very roughly slap on some poly – that’s all I’ve really done before. Now that the Christmas rush is over, I’ll do some reading and be ready for the next project.

-- Ryan -- Bristow, VA

View Todd A. Clippinger's profile

Todd A. Clippinger

8901 posts in 4096 days

#10 posted 12-27-2010 08:59 PM

Good to hear the end result worked out.

I have found out over time that most people do not see the minor imperfections that you have become intimately knowledgable of when you work on a piece.

Learn to just not say anything and nobody will ever know.

Am I being deceitful? No. Just being real.

I don’t reach for unrealistic perfection, just excellence. I accept the difference between the two.

-- Todd A. Clippinger, Montana,

View SnowyRiver's profile


51457 posts in 3476 days

#11 posted 12-27-2010 10:02 PM

Glad you got it worked out Ryan. I agree with Steven, try a good quality brush next time. I have always used a brush and find it works best for me.

-- Wayne - Plymouth MN

View DaddyZ's profile


2475 posts in 3037 days

#12 posted 12-27-2010 10:22 PM

I use the foam Pads & had luck with putting on a good coat of finish, then take a can with nothing but mineral spirits in it soak your brush then cover the finish with it. when the finish lays back down – No Brush Marks !! I have done several times works each time.

-- Pat - Worker of Wood, Collector of Tools, Father of one

View fussy's profile


980 posts in 3047 days

#13 posted 12-27-2010 10:57 PM


I’m glad you got it worked out. You’ve been in a panick and worked your butt off, and you GOT IT DONE! Now relax and think over all the advice you got, try different methods on scrap to fin what works best for you. They all work, but you will like one better than the rest, and that should be the method you use most of the time. Big thing is it’s done, your Mother-in Law is happy, therefore your Wife is happy, so that YOU can be happy; so BE HAPPY! Stay safe.


-- Steve in KY. 44 years so far with my lovely bride. Think I'll keep her.

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