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Tiny bubbles on water based poly

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Forum topic by TOPO posted 04-17-2012 04:31 PM 1660 views 0 times favorited 21 replies Add to Favorites Watch
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TOPO

14 posts in 1173 days


04-17-2012 04:31 PM

Topic tags/keywords: question bubbles poly water

Hi mates, being based in Spain, is difficult to use the same brands of finishes that you are using to I will skip brand names here, and they won´t make sense :-)
Issue I have is happening with three different brands of water based poly. All of them are quite thick, kind of almost gel consistency, but they flow very well when used. the problem I have is that when applying them, even with the lightests of my brush strokes, or with a foam pad, I´m getting very tiny bubbles all over the place. If I overbrush with only the tip, very slow and faintly, I get rid of some of them, but the remaining will be perceived when totally dry. A quick rub with fine sandpaper, solve the touch issue, but the bubble shapes remain as tiny circles on the wood. That is not a big problem in heavy figured woods, but on clear dark ones, they show as a shore thumb when the light strikes skewed.
Have you find this problem before? I tried with good quality synthetic and natural brushes, foam pads and even with cloth, but I always had the same issue. The cans were not shaken but stirred, and I avoided to discharge the brush against the lid, as some googling suggested… I´m running out of ideas.. could the that is too thick/liquid?

Any suggestions is more than welcome, I prefer to test 20 different solution than fry my brain thinking in what I´m doing badly….

Many thanks in advance, and regards from Spain!

Luis S.

-- El Topo, Madrid (Spain)


21 replies so far

View pintodeluxe's profile

pintodeluxe

3513 posts in 1532 days


#1 posted 04-17-2012 04:38 PM

Stirring the poly instead of shaking it may help.
I think the only way to get rid of bubbles is to spray a finish like lacquer, or perhaps try a thinner wipe-on poly.

-- Willie, Washington "If You Choose Not To Decide, You Still Have Made a Choice" - Rush

View CharlieM1958's profile

CharlieM1958

15712 posts in 2937 days


#2 posted 04-17-2012 04:54 PM

Try rubbing out the surface with automotive polishing compound. If the bubble remnants are just on the surface, that might get rid of them.

Also, as Willie said, stir gently rather than shake. And you could always try thinning it a bit to give the bubbles more time to surface and level themselves before the finish dries.

-- Charlie M. "Woodworking - patience = firewood"

View RussellAP's profile

RussellAP

2963 posts in 1005 days


#3 posted 04-17-2012 04:54 PM

I’d experiment with some thinner which will let it smooth out on it’s own rather than modify the application process.

-- A positive attitude will take you much further than positive thinking ever will.

View crank49's profile

crank49

3481 posts in 1690 days


#4 posted 04-17-2012 05:29 PM

You have done everything I would have done. Different brushes, foam pad, cloth, etc.
You state that you stir lightly and do not shake.
All this is good.

Only two ideas I have left and one of them has already been suggested; thin the poly.

The other is unconventional for wood working, but a process I bring from jewelry manufacturing experience. You can literally pull the bubbles from the poly while it is in the can with a vacuum pump.
A high vacuum, greater than 28.5” (725mm) WC, will cause the tiny bubbles to expand and float up to the surface and pop. Normally about 2 minutes will do the trick. Note, this must be done in a vacuum tank or other pressure vessel, not the can directly. It would be crushed. I have used an old pressure cooker my wife no longer uses.

-- Michael :-{| “If you tell a big enough lie and tell it frequently enough, it will be believed.” ― A H

View Bill White's profile

Bill White

3529 posts in 2679 days


#5 posted 04-17-2012 05:40 PM

No foam brushes period. No shaking either, just stir. A product in the states called FLOETROL is a “retarder” that really helps WB products flow out without bubbles. Made by Akzo Nobel Paints LLC.
I use a synthetic bristle “finishing” brush.
Maybe this will help.
Bill

-- bill@magraphics.us

View Loren's profile

Loren

7808 posts in 2367 days


#6 posted 04-17-2012 05:58 PM

Generally poly comes too think in the can to brush really well.

You might experiment with padding on the finish like shellac.

-- http://lawoodworking.com

View Lee Barker's profile

Lee Barker

2169 posts in 1569 days


#7 posted 04-17-2012 05:59 PM

I agree you’re on the right track. Stirring is good, not scraping the brush is good.

When you say “quality brush” are you including the Gramercy brush?

I discuss my recent discovery of this tool here.

Also are you straining your product with this kind of seive? It’s a very good habit to use these every time.

Kindly,

Lee

-- "...in his brain, which is as dry as the remainder biscuit after a voyage, he hath strange places cramm'd with observation, the which he vents in mangled forms." --Shakespeare, "As You Like It"

View Dallas's profile

Dallas

3094 posts in 1206 days


#8 posted 04-17-2012 06:13 PM

Just my way….

I use foam I’ve cut from a piece of tractor cab insulation, closed cell, black, heavy.

I use a hot knife to cut it so I get clean, even slices.

I wet the foam, squeeze it and let it sit on an angle for 20 minutes or so before using it.

Not knowing the characteristics of the WB poly you are using, it’s difficult to say what is wrong.

The WB poly I’ve been using is Rustoleum and Minwax. Look up the properties of each and see how they differ from what you are using.

-- Improvise.... Adapt...... Overcome!

View poopiekat's profile

poopiekat

3709 posts in 2453 days


#9 posted 04-17-2012 07:09 PM

I’m just glad that Charlie M did not burst into song, ala Don Ho.

-- Einstein: "The intuitive mind is a sacred gift, and the rational mind is a faithful servant. We have created a society that honors the servant and has forgotten the gift." I'm Poopiekat!!

View CharlieM1958's profile

CharlieM1958

15712 posts in 2937 days


#10 posted 04-17-2012 07:42 PM

I had to think about that one for a minute before it sunk in, Poopie.

-- Charlie M. "Woodworking - patience = firewood"

View TOPO's profile

TOPO

14 posts in 1173 days


#11 posted 04-17-2012 08:02 PM

Hey! many thanks for the answers… I will try to reply all of them :-)

Gramercy tools in Spain are a dream to get :-( I will be travelling to Seattle in June, so maybe I can get them shipped there, will love to test something that looks so finely made.

Never heard about floetrol, but will try to find it here!

The pressure vessel, well looks really interesting to perform…

And straining the fluid was not tried before, so maybe I will look around for those filters here…

The thinning process, looks promising, and easier to try, I will try it and keep you posted!

Thanks a lot for all the answers, I really appreciate the willinges of everybody to help here…

Best regards!

Luis

-- El Topo, Madrid (Spain)

View RussellAP's profile

RussellAP

2963 posts in 1005 days


#12 posted 04-17-2012 08:04 PM

I would think that straining it would produce more bubbles.

-- A positive attitude will take you much further than positive thinking ever will.

View Lee Barker's profile

Lee Barker

2169 posts in 1569 days


#13 posted 04-17-2012 08:34 PM

It doesn’t seem to, but next time I’ll watch closely. The strainers I use, purchased from an auto body supply shop, are extremely fine.

Kindly,

Lee

-- "...in his brain, which is as dry as the remainder biscuit after a voyage, he hath strange places cramm'd with observation, the which he vents in mangled forms." --Shakespeare, "As You Like It"

View RussellAP's profile

RussellAP

2963 posts in 1005 days


#14 posted 04-17-2012 08:37 PM

Does anybody else have Dean Martin singing Tiny Bubbles stuck in their head?

-- A positive attitude will take you much further than positive thinking ever will.

View Philzoel's profile

Philzoel

277 posts in 1062 days


#15 posted 04-17-2012 09:14 PM

I used to have bubbles. None any more. Clean surface really well after sanding. Mineral spirits works great.

Why do you use water based? It does not yellow, but it does not hold up well and is not water proof.

-- Phil Zoeller louisville, KY

showing 1 through 15 of 21 replies

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