Brush marks in my finish

5678 Views 18 Replies 10 Participants Last post by DesertRatTom, Jul 14, 2017

billyjim

Discussion Starter · Jul 12, 2017

I recently decided to try a stain-poly mix when I was finishing a couple of projects. My problem is that I can not eliminate brush marks from showing in the dried finish. I have tried 4 times now to get a final coat on but each time I get a few brush marks which mar the appearance. I am about ready to give up and just top it off with either a wipe-on poly or a spray poly. Anybody have any luck using the stain-poly mix?

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1 - 19 of 19 Posts

hawkeye10

· #2 · Jul 12, 2017

Bill I know you already know this but be sure and use a high quality brush and take light long strokes for the final strokes. Also don't forget to clean your brush. It will last for years.

Reactions: 2

Cherryville Chuck

· #3 · Jul 12, 2017

I think it's because the finish is drying too fast. I don't remember this being a problem many years ago when finishes took 24 hours to dry but it did become a problem when they went to 1 to 4 hours drying time. The finish dries before surface tension can self level the finish. Try using it under the slowest possible drying environment and maybe use a foam brush for the final coat. Make sure you have removed the brush strikes from previous layers or they will telegraph through. Another possibility is to use a hair dryer on any brush strokes you see. It might work. It's one way to get rid of bubbles in a finish so it might smooth out brush strokes too. Otis uses a propane torch for that. It might work too but you would have to be more careful and I wouldn't use it on an oil based finish.

Reactions: 1

sunnybob

· #4 · Jul 12, 2017

why not just wipe it on?

Cant see there would be much difference between a stain poly and a wipe on poly.

With the wipe on you can literally wipe ecerything off after applying. It might take two or three coats, but there will be no brush marks.

Reactions: 1

DesertRatTom

· #5 · Jul 12, 2017

I recently saw a video of a finishing class in which the teacher used a folded paper towel instead of a brush to apply the poly. No brush marks at all in any of the items (mostly picture frames) I've made using the method. The poly is pretty volatile, and it may have thickened from sitting open. Where you live is pretty hot so drying time has got to be pretty short, so thinning the poly a bit probably wouldn't hurt. But do try folding paper towels into a brush shape and applying each coat of poly fairly quickly.

Reactions: 1

Cherryville Chuck

· #6 · Jul 12, 2017

DesertRatTom said:
I recently saw a video of a finishing class in which the teacher used a folded paper towel instead of a brush to apply the poly. No brush marks at all in any of the items (mostly picture frames) I've made using the method. The poly is pretty volatile, and it may have thickened from sitting open. Where you live is pretty hot so drying time has got to be pretty short, so thinning the poly a bit probably wouldn't hurt. But do try folding paper towels into a brush shape and applying each coat of poly fairly quickly.

Reactions: 1

FreeTime

· #7 · Jul 13, 2017

I usually have better luck with foam brushes and the hair dryer / heat gun idea works well too for any bubbles.

kywoodchopper

· #8 · Jul 13, 2017

Hi Bill, I apply Zar polyurethane all the time, but never a stain. As others have said, use a paper towel. I use the blue shop towels that I cut into 1/4. Then I fold until it is about 2" square. I dilute the poly almost 50% with quality mineral spirits. I apply 2-coats a day. No runs and no brush makes and no sanding between coats.

Most woods after a couple coats I apply a heavy coat with a 1" foam brush and go over it with the orbital sander on medium speed using a 400 grit wet / dry sandpaper. This really mades the wood slick and seems to help the grain. I let that dry for 12 hours or so then apply a couple more coats with the towel. Then I use a 500 grit foam pad that fits on the orbital sander that I go over the piece lightly to removed any grit or dust. Then apply the last coat of poly.

Hope this help. Malcolm / Kentucky USA

Reactions: 1

billyjim

Discussion Starter · #9 · Jul 13, 2017

Cherryville Chuck said:
I think it's because the finish is drying too fast. I don't remember this being a problem many years ago when finishes took 24 hours to dry but it did become a problem when they went to 1 to 4 hours drying time. The finish dries before surface tension can self level the finish. Try using it under the slowest possible drying environment and maybe use a foam brush for the final coat. Make sure you have removed the brush strikes from previous layers or they will telegraph through. Another possibility is to use a hair dryer on any brush strokes you see. It might work. It's one way to get rid of bubbles in a finish so it might smooth out brush strokes too. Otis uses a propane torch for that. It might work too but you would have to be more careful and I wouldn't use it on an oil based finish.

I have been using a foam brush on the last coat. I think the drying time might be the culprit here. That plus the poly getting thicker from being open. I might try cutting it a bit and see how that works.

billyjim

Discussion Starter · #10 · Jul 13, 2017

DesertRatTom said:
I recently saw a video of a finishing class in which the teacher used a folded paper towel instead of a brush to apply the poly. No brush marks at all in any of the items (mostly picture frames) I've made using the method. The poly is pretty volatile, and it may have thickened from sitting open. Where you live is pretty hot so drying time has got to be pretty short, so thinning the poly a bit probably wouldn't hurt. But do try folding paper towels into a brush shape and applying each coat of poly fairly quickly.

Tom I think you are right in saying the poly has thickened up. I am going to try cutting it a bit and see if that works. I use foam brushes but I am going to try the paper towel and see how that does.

Reactions: 1

billyjim

Discussion Starter · #11 · Jul 13, 2017

kywoodchopper said:
Hi Bill, I apply Zar polyurethane all the time, but never a stain. As others have said, use a paper towel. I use the blue shop towels that I cut into 1/4. Then I fold until it is about 2" square. I dilute the poly almost 50% with quality mineral spirits. I apply 2-coats a day. No runs and no brush makes and no sanding between coats.

Most woods after a couple coats I apply a heavy coat with a 1" foam brush and go over it with the orbital sander on medium speed using a 400 grit wet / dry sandpaper. This really mades the wood slick and seems to help the grain. I let that dry for 12 hours or so then apply a couple more coats with the towel. Then I use a 500 grit foam pad that fits on the orbital sander that I go over the piece lightly to removed any grit or dust. Then apply the last coat of poly.

Hope this help. Malcolm / Kentucky USA

Thanks Malcolm. I am going to give this a try. If it turns out even close to your boxes I would be a happy camper.

DesertRatTom

· #12 · Jul 13, 2017 (Edited)

2

I use disposable chip brushes for staining these days, it makes it easy to work stain into crevices on picture frames, which are my most frequent project. I use a prestain as well, which produces better results than applying to bare wood.

I like the paper towel results very well indeed. Use the corners to apply the poly to those tight spots. I also use disposable clear plastic food cups, pour in enough poly for one coat, then squeeze out all the air and close the plastic bottle. I put a lid on the 2 ounce food container if it has to sit more than a minute. Haven't noticed much thickening as a result, but I also have mineral spirits handy. I used a Forstner bit to drill a recess into a short 2x4 to hold the food container, without it, you WILL get a spill.

Sanding picture frames was no fun until I discovered these sanding pads and the new, flexible 3-M sanding sheets. The sheets conform to the shape of the pad, both the U shape and the rounded end and sanding is done in minutes on picture frame stock. Best $10 investment in accessories yet. I generally sand down to 220 grit, with the occasional quick pass with 320 grit to lightly clip off the fuzz that gets raised by the stain. The 3M sheets are really aggressive, almost like card scraping. Next comes a large paint brush to remove the bulk of sawdust, then a very light rub with a waxed cheese cloth to knock off the dust. For picture frames, I'm generally going for a very high gloss, glassy finish. I highly recommend the sanding blocks, which you can get in angled and curved versions from Amazon or woodworking stores..

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Reactions: 1

billyjim

Discussion Starter · #13 · Jul 13, 2017

DesertRatTom said:
I use disposable chip brushes for staining these days, it makes it easy to work stain into crevices on picture frames, which are my most frequent project. I use a prestain as well, which produces better results than applying to bare wood.

I like the paper towel results very well indeed. Use the corners to apply the poly to those tight spots. I also use disposable clear plastic food cups, pour in enough poly for one coat, then squeeze out all the air and close the plastic bottle. I put a lid on the 2 ounce food container if it has to sit more than a minute. Haven't noticed much thickening as a result, but I also have mineral spirits handy. I used a Forstner bit to drill a recess into a short 2x4 to hold the food container, without it, you WILL get a spill.

Sanding picture frames was no fun until I discovered these sanding pads and the new, flexible 3-M sanding sheets. The sheets conform to the shape of the pad, both the U shape and the rounded end and sanding is done in minutes on picture frame stock. Best $10 investment in accessories yet. I generally sand down to 220 grit, with the occasional quick pass with 320 grit to lightly clip off the fuzz that gets raised by the stain. The 3M sheets are really aggressive, almost like card scraping. Next comes a large paint brush to remove the bulk of sawdust, then a very light rub with a waxed cheese cloth to knock off the dust. For picture frames, I'm generally going for a very high gloss, glassy finish. I highly recommend the sanding blocks, which you can get in angled and curved versions from Amazon or woodworking stores..

I have not had good luck with the disposable chip brushes. They tend to lose bristles. Where do you buy yours?

N'awlins77

· #14 · Jul 13, 2017

Bill I tried using that poly/stain mix too, and I didn't like it either. I don't remember that it was the brush marks or not, I just remember I didn't like it.

Reactions: 1

DaninVan

· #15 · Jul 13, 2017 (Edited)

Bill; just out of curiosity, why did you go to the stain~poly mix? Were you having difficulties with the stain you were using previously, or was it a time saving thing?

Is the product you're using now a Minwax stain~poly?

JOAT

· #16 · Jul 13, 2017

Interesting. I would have said wipe it on too, but too many beat me to it. First I ever heard of using paper towels tho, but that sounds like a good idea.

In truth, it's been so long since I used anything but thinned Titebond II as a finish, I don't recall if I ever had problems with brush streaks or not, but certainly don't remember any.

I have never seen any brush marks in any of my Titebond finishes. Could be some, but if so never noticed any. The Titebond is ready for more coats in a very short time, maybe 15 minutes or so max, never timed it. I use reasonably good nylon brushes. Thinking about it, I think that the Titebond is thinned so much, it not only dries fast, but it tends to level out after applying. One of these days I'll try some stain in it, and see how that works out.

billyjim

Discussion Starter · #17 · Jul 13, 2017

DaninVan said:
Bill; just out of curiosity, why did you go to the stain~poly mix? Were you having difficulties with the stain you were using previously, or was it a time saving thing?

Is the product you're using now a Minwax stain~poly?

Dan I tried this thinking it might save me some time but it has cost me considerably more in time and effort than using a stain followed by poly. And yes the product is a Mini-wax stain-poly.

DaninVan

· #18 · Jul 14, 2017

Mom Always Said...

billyjim said:
Dan I tried this thinking it might save me some time but it has cost me considerably more in time and effort than using a stain followed by poly. And yes the product is a Mini-wax stain-poly.

*Lips are sealed*

DesertRatTom

· #19 · Jul 14, 2017

billyjim said:
I have not had good luck with the disposable chip brushes. They tend to lose bristles. Where do you buy yours?

Got them in bulk from Amazon in batches of 50. I have half inch, one inch and 1.5 inch (although I rarely use the last). I only use them for staining and for padding forms.

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