# Applying polyurethane faster, how?



## VIVA (Nov 4, 2008)

Hi, there!

I'm newbie to this forum, but have some skills in woodworking.

Have there a way, to apply polyurethane (water-based in this case) fast and acurate.

The poroblem is - when i'm working on finish accurately, without leaving large runs and brush marks, which coudn't be sanded out later. Increasing the speed of working, makes this process give worser results.

My favorite problem is runs on edges and corners, althouth making a very thin layers...

Whats the clue in?

Thanks for further answers!

P.S> Sorry for my english, it's not my native.


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## user4178 (Apr 18, 2008)

Yeah, your hard to understand, but I think I know what your saying. Patience and experience is the key, weather your brushing or spraying.


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## VIVA (Nov 4, 2008)

Woodchuck1957 said:


> Yeah, your hard to understand, but I think I know what your saying. Patience and experience is the key, weather your brushing or spraying.


Sorry again, hope practice will help to communicate better.

"Patience" method mastered. But still want to find out how to escape runs on edges. While moving brush from center to edges, leaving runs on top surface. While moving vise versa - leaving on the side edge. 

Is the sequensce right?
1) Top surface (leaving runs on sides)
2) Remove runs on sides
3) Carefully cover side egdes

BTW Woodchuck1957, am i wrong with times, terms or style? (about text)


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## user4178 (Apr 18, 2008)

The only way I know how to minimize runs is have a bright light shineing on your work and constantly check it for runs before they setup so you can feather them out. I usually brush from side to side, not center to side.


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## skymaster (Oct 30, 2006)

Chuck; sounds like he is putting it on a tad too heavy. Several lightcoats are better than one thick heavy coat. :}:}:smile:


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## VIVA (Nov 4, 2008)

skymaster said:


> Chuck; sounds like he is putting it on a tad too heavy. Several lightcoats are better than one thick heavy coat. :}:}:smile:


You heard me wrong. I'm putting very light layers, And setted a 4 point lights, so workarea is bright enougth... I thought, that there have a method working with brush, that NOT leaving runs... In "patience" method i'm carefully feather them out along the grain of base, center-to-edge, But this slows down process generally.

BTW, is it important to follow some exact direction while feathering runs?


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## user4178 (Apr 18, 2008)

I agree Sky, and I think he's in too big of a hurry. Fast and accurate usually aren't used in the same sentence when doing something manually. I knew a young painter ( about 30 yrs old ) that had quite a few years of experience brag to me about how fast he was and that he was the best. I just laughed, and said, either your fast, or your the best, you can't be both.


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## skymaster (Oct 30, 2006)

Viva; Am NOT pikin on ya :}:} getting runs normally indicates too heavy a coat. For what is is worth I dont worry about which way I first apply the poly, however once I get a coat on I always,brush it out with long strokes in the grain direction; IE all the along the longest length nonstop. Brush it out edges also then let it dry. If there are runs or drips they will be at the bottoms of the edges. Then I use razor blade to trim em from BACK side, then apply to back LIGHTLY brush out well and trilple check that nothing drips toward the front. SPEED is your enemy! Stop rushing and it will go faster :}:}:}. BEST way is to spray if you want no runs etc, this will cost money but is the best way I believe there is a product that you can use to thin it a bit which will help alot.

Chuck; :}:} I wasnt ranting at you LOL LOL in the other blog:laughing::yes: I am JUST really twisted aroung the axle yet :shifty::huh:


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## cabinetman (Jul 5, 2007)

VIVA said:


> Hi, there!
> 
> I'm newbie to this forum, but have some skills in woodworking.
> 
> ...



There are a few details you might consider. First, if the poly you are using is intended as a spray, it may be too thin to brush down. If you are thinning your material too much, you will have the same problem. Check the directions on the can for application, to determine what you are using.

Next, it may be the brush you are using. A good synthetic bristle brush is recommended. It won't carry as much material as a natural hair brush, which could be a cause for runs. 

The type of brush should allow enough material to be laid down and drawn smoothly. Technique will eliminate some of the problem. You may try drawing the pattern towards the ends and from the inside corners out as a final stroke. Once a surface gets a wet coat, adding more material with an additional stroke is loading up too much. The trick in brushing is to get it on and move on. You don't want to do excessive brush strokes. You'll develop a feel for how much material you can brush with the brush pressure and using the flexibility of the bristles.

If you have the option to spray, that will produce a very fine finish.


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## user4178 (Apr 18, 2008)

skymaster said:


> Chuck; :}:} I wasnt ranting at you LOL LOL in the other blog:laughing::yes: I am JUST really twisted aroung the axle yet :shifty::huh:


Sky, it's ok.


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## BHOFM (Oct 14, 2008)

It could be as simple as using too large a brush. 
I tend to use too small a brush.

I like the cheap chip brushes, I give them a good
cleaning first, and pull on the bristles to get any
loose ones out.

I have never had a problem with runs in water base
finishes. 

You don't paint from then edges, you paint to the edges.

I get as much material out of the brush as I can
and go lightly over the edges when I finish.


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## Davet (Nov 16, 2007)

cabinetman said:


> If you have the option to spray, that will produce a very fine finish.


Don't mean to steal this thread but what kind of poly do you
recommend for spraying, is thinning the poly with about 10%
mineral spirits about right.

Dave


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## mainzy (Mar 8, 2008)

viva; if your looking for speed you need to get away from poly and invest in a cheep(for now) spray gun. conversion varnish is the way to go. You can do a sealer coat and 2 top coats in just a few hours. The only problem may be ventilation.

God Bless;Mainzy


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## cabinetman (Jul 5, 2007)

Davet said:


> Don't mean to steal this thread but what kind of poly do you
> recommend for spraying, is thinning the poly with about 10%
> mineral spirits about right.
> 
> Dave



This thread is about using waterbased polyurethane, which would be thinned with water. 

Oil base polyurethane would be thinned with either mineral spirits or naptha.


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## Tony B (Jul 30, 2008)

*Drips and runs are caused by....*

either putting it on too thick or too much thinning or both.
If its too thick, the surface tension is overcome by gravity. Too much thinning and the surface tension of the chemicals is reduced.
Surface tension is a physical phenomenon that keeps all things held together. A good example of surface tension in liquids is sometimes when you spill water on a table, it will kinda bead up at the edge and not drip over the side. If you were able to 'thin' the water out with soap and duplicate the same spill, the thinned water will bead less and spill over the edge. If you spill gasoline it lays out thin......very little surface tension.

Sorry about the rant, but I hope it helps.


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## Teenagewoodworker (Nov 2, 2008)

have you tried wiping it on. that could work. or i would invest in a spray gun. earlax makes a good one or you can get a huskey at Home Depot. thats the gun that i have. spraying works very well. it takes some practice but again works great once you get the hang of it. and i don't think you are doing it really too heavy. its just the natural of brushing. if you go off the edge you are going to get drips on the edge because the brush pushes some finish in front of it which goes off the edge and drips.


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## jdixon (Nov 21, 2007)

Viva, your communication is fine. No need to apologize. You sure don't see any of us responding back to you in Russian do you?

I kinda prescribe to what cabinetman said re: brush quality. I also tend to always go with the grain when applying anything but that may be just my neurotic side.

John


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## djonesax (Mar 3, 2008)

To me staining and finishing is the hardest part of woodworking. And consequently the most stressful  I have tried the most expensive brushes and making sure to put on light coats. I still have problems. I evidently don't have a good hand or I'm just not experienced enough. 

If I have to brush poly I try to do a side at a time and lay the piece flat. I keep a paper towel on had to wipe up the drips from the sides. 

On a couple recent projects I have had really good results from spray cans believe it or not. I used about 4 spray cans on 3 6ft panels for a folding screen. It turned out better than anything I have ever brushed.

My last project I sprayed lacquer as the finish and I will probably if I can help it never go back to poly unless the project requires it. It dries so fast and I didn't have a single run.

In the case where you must use poly you could try a wipe on poly to reduce the amount of runs but it may end up taking you more time because you need more coats. 

If its speed you want do like Teenagewoodworker said and get a decent spray gun and compressor and spray lacquer. I sprayed 2 coats a 3 x 6 foot panel for a bookcase on my lunch break last week. I did the entire book case with 3 coats and was done and handling it in I think 2 hours if I remember correctly.

David


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## VIVA (Nov 4, 2008)

WOW... Lot of texts! =)

Work taken a lot of time, sorry for absence.



cabinetman said:


> First, if the poly you are using is intended as a spray, it may be too thin to brush down. If you are thinning your material too much, you will have the same problem. Check the directions on the can for application, to determine what you are using.


Em. I'm using a Varathane Diamond Polyurethane. And it's definetly not for spraying. BTW, i have a habbit to read manufacturer's directions, just in case.



cabinetman said:


> Next, it may be the brush you are using. A good synthetic bristle brush is recommended. It won't carry as much material as a natural hair brush, which could be a cause for runs.
> 
> The type of brush should allow enough material to be laid down and drawn smoothly.


I'm using a synthetic brush. Manufactured by PPG (Pittsburgh Paints). Here, at Varathane dealer shop, it costs slightly less than 10$.



cabinetman said:


> Technique will eliminate some of the problem. You may try drawing the pattern towards the ends and from the inside corners out as a final stroke. Once a surface gets a wet coat, adding more material with an additional stroke is loading up too much. The trick in brushing is to get it on and move on. You don't want to do excessive brush strokes. You'll develop a feel for how much material you can brush with the brush pressure and using the flexibility of the bristles.
> 
> If you have the option to spray, that will produce a very fine finish.


That is closest answer. In fact, in my beginnings, i was learned, that there is not necessary to put a coat without brushmarks. Put 3-6 thin coats, without runs, and than sand out the marks. That was great, until i learned better to see the quality of finishing. This way applied coat, from some angles have noticable brushmarks. I've tried to sand more, and sanded through (i don't know this trem in english).
So, that meant to me, that the clue in brush technique.

I have no option to spray, but seems, that it would be necessary to get it. 

Thoughts that brush gives same or better quality finish is wrong? Or right, but takes much longer time?


djonesax, generally i like this poly, and want to apply IT perfectly (or alomost perfectly) +) BTW, My poly dries from dust for 5-10 min =\ 

Teenagewoodworker, wipe-on is an interesting way, but not for now to me.

Generally, the key to go faster withiout losing quality - is HVLP or smth like... Hm....

Will try further using your advices, and aspectially - cabinetman's.


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## chevyll_1967 (Aug 7, 2008)

I've used sponge brush before and seems to have less runs than ordinary brush.


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## annex greg (Nov 10, 2008)

Hi, I have found water-based polys to preform vastly different one from another, as well the technology has been improving over the years. Interestingly enough the best waterbased lacquers and polys seem to come from Italy. As I understand it they have have had regulatory people over there longer than we have had them over here. I live and work in California and so we have the strictest regulations in the union so much so that most of the large furniture manufactures we had in the area have moved out of state. The point being, that I have been searching for water based materials that meet the looks and feel of nitro lacquer. Having experimented with many different brands the best I have found is from a manufacture called Renner. I have had great luck with all there materials, as far as application the only way I would go would be to spray it on, the trick being with spraying a water based material is that you have to use a gun with a large tip usually a 2.0 mm. I have found the hard way that the smaller tip sizes put out a very poor finish. That in fact is one of the main reasons I have seen failures with the water based materials and people trying to switch over to them is that they unwittingly do not have the correct equipment and incorrectly think that the water based materials are going to go through the gun that they have been spraying their Nitrocellious lacquers with. I have on my blog a very good article on spray basics written be a fellow finisher Thomas Craven if you would like to have a quick "How to" on the subject. http://woodfinishings.wordpress.com 

All that being said if I had to do a coating and didn't have a spray gun I would go with what chevyll_1967 mentiond and that would be using a sponge. and build light coates. 

One of the technical differences inbetwee the nitrocellious lacquers and the water based lacquers and Poly's is that the nitro when applied will melt in to the previouse coate, solvants in the mix disove the earlier coating and so you get that solvant lacquer smoothness and the water based lacquers don't do that. consiquently the thing to do is to layer it up slowly and then sand the heck out of it to get the smoothness desired and then lay on a final coate with enought retarder in it for it to level out befor drying. For California where it is hot and dry that is sometimes necessary If youare in the cold and damp area that might not be necessary. 

Greg


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