# Micro Bubbles Everywhere



## DeanV (Apr 18, 2007)

Are there specific conditions that cause micro bubbles? All pigmented finishes.

I have had a rash of micro bubbles in our shop. 

First, with Kem Aqua Plus low gloss, we got rid of it by thinning a bit with butyl cellusolve. HVLP and airless, everything went fine.

Next, we did a few doors with the mid gloss Kem Aqua plus. Micro bubbles no matter what. HVLP or airless. Also cracks badly over caulk (the low gloss did not).

Zenith WB conversion varnish. Water and ethylene glycol both still micro bubbled. Airless application. All airless applications were 310 FFLP tips. HVLP air bubbles as well. We could get it to look good, but not feel perfect.

Now, airless with Emerald Urethane semigloss also micro bubbles with airless application. We added water and it still micro bubbles, but it looks like they dissipate before the film dries enough to trap them in.

Historically I have not had a problem with micro bubbles. At least not wide spread, maybe an occasional piece here or there.

I cannot figure this one out. I am not sure if winter air in MI is the problem (too dry maybe). We cannot control humidity in our shop. We heat our spray room with a normal furnace but it can't keep up with the the temp when the fan is running. We have tried spraying with and without the booth fan running, no difference. We often kill the heat for 15 minutes after spraying to let coatings flow out, release any bubbles, etc before drying. No difference either way.

Any thoughts?


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## PACman (Oct 24, 2014)

I've been posting on here about the microbubble issue for a couple of years now. But the first thing you need to do is actually determine if they are actually bubbles or microspheres. Look at them through a 10x magnification and try to poke them with a needle. If they are microbubbles you will be able to see the needle tip go into the hole or stick through the bubble. If it is a microsphere it will be hard. I have seen both in various pigmented products from certain companies for a few years now.

For example i am in the process of testing a brand spanking new waterbourne ceramic, and i need to have a nice smooth primed surface to make a good test/sample board. Not one of the readily available aerosol primers and most of the common brush on primers can be put on a surface without microbubbling. It is becoming very prevalent the last couple of years in particular. I even had a problem with aerosol bin, which was quite a surprise to me as that is (was) one of my favorite common primers. Three light coats and the microbubbles just keep coming through. I really don't know what the cause of the issue is to be honest with you.


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## DeanV (Apr 18, 2007)

I am pretty confident they are micro bubbles. They seem to dissipate mostly on their own, but some remain. Sometimes, if you look really close you can tell it pops and forms a crater as it dries.

Could be some of both I suppose as well.


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## PACman (Oct 24, 2014)

DeanV said:


> I am pretty confident they are micro bubbles. They seem to dissipate mostly on their own, but some remain. Sometimes, if you look really close you can tell it pops and forms a crater as it dries.
> 
> Could be some of both I suppose as well.


if you can definitely see a crater it is a bubble, but i have been fooled myself on several occasions. Are you or anyone else shaking the product? I wouldn't think that would be an issue with Kem aqua or Emerald, but it could def be the issue with the conversion varnish. You could try mixing it with a drill mixer very slowly and see if any bubbles start to come to the surface in the can. If they do then the bubbles are there before you start spraying.

Do you ever use any spray lubricant in your shop? You'd be surprised how long some of those tiny particles can stay airborne. They can even attach to dust particles. Have you talked to a SW chemical coating rep yet?


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## DeanV (Apr 18, 2007)

I talked to my independent BM dealer rep. They also make their own paint, so he is quite knowledgable. He suggest thinning a bit. He has seen this lately as well. For the the other guy, thinning did the trick.

We are stirring the products, not shaking.

I tried a new FFLP tip just now. Still not perfect. But, it will probably need to be good enough. 

I just tried a different product (Repcolite Ceramic Satin) sprayed through the same pump with just a quick flush of the SW Emerald Urethane out. And I can tell there will be no issues as soon as I finished spraying. No bubbles, nothing out of the ordinary. It sprayed just like most paints always do for me in the shop. Especially on flat cabinet doors. 

I don't get it. I guess the motto has to be be stay away from SW. And see if I can figure out the Zenith stuff.


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## Ric (Oct 26, 2011)

DeanV said:


> Are there specific conditions that cause micro bubbles? All pigmented finishes.
> 
> I have had a rash of micro bubbles in our shop.
> 
> ...


Hey Dean,

I'm gonna take a guess here, but I'd say what you're experiencing is probably solvent pop, and that idea is kind of supported by your statements butyl cellusolve helped to reduce them (somewhat), and that most of the "bubbles" will ultimately correct themselves. One more reason for this thought is Kem Aqua Plus contains a fast drying alcohol (2-methoxymethylethoxy)propanol that can sometimes misbehave (similar to acetone in oil/alkyd products) and result in solvent pop. Typically, application when surface & air temps are between 70-80 degrees F. with low humidity should, possibly, hopefully, may take care of the micro-bubbling - but you also may want to make sure your applied thickness doesn't exceed 3-4 mils wet. I hope this helps - good luck.


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## stelzerpaintinginc. (May 9, 2012)

*Solvent Pop*

Dean, have you tried increasing your ratio of Butyl Cellosolve? What ratio are you at now? How do you go about incorporating it into your paint? How fast are you adding it to your paint? 

I'm getting ready to do a cabinet job in my shop now and will probably pull the humidifier out, since the relative humidity is so low. If you don't have one, you could always pick one up for less than $30. It's a safer alternative than adding too much butyl for sure. 

I'm with Ric on this one though. It sounds like Solvent Pop. Increasing RH might do the trick. Please follow up though once you figure it out. Interested in what the culprit was and what you do to resolve it. Good luck.


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## DeanV (Apr 18, 2007)

I don't understand it yet.

I do not know what Emerald Urethane did it, but a Ceramic Satin did not.

Low gloss KemAqua had minimal issues, a couple splashes per gallon did the trick. 

Mid gloss KemAqua plus, nothing helped. 

Zenith: Nothing helped. Water was the recommendation there (4-5 oz per gallon). 

As far as a humidifier, I am not sure that by the time I ran the spray exhaust fan it would make a difference. I could not run the booth fan to keep the humid air in. I need to find my humidity meter again.

I will need to get some scrap doors and figure out what is going on. I couldn't get it dialed in yet.


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## Tprice2193 (Oct 3, 2017)

I am thinking solvent pop aggravated by a little extra milage, low humidity, and heat. I run into it when I put on the Kem Aqua Plus a little too thick trying to float out my final coat. Most of them pop on their own...some require a little help...a few come up after I stop looking. Maybe as simple as turning the heat down 5 degrees F.


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## PACman (Oct 24, 2014)

Is this the clear or pigmented Kem Aqua plus?

anyway here is the data sheet for the pigmented. Notice that it says that it is less prone to microfoaming than other water borne clears! There is some good information regarding humidity and force drying that may be helpful. There is also a comment about airless application and microfoaming.


https://www.paintdocs.com/docs/webPDF.jsp?SITEID=SWOEM&lang=E&doctype=PDS&prodno=M64W522


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## Wolfgang (Nov 16, 2008)

If you use the butyl in the Kem Aqua, use a little alcohol in it also. I've also used distilled water for thinning some of the latex's and it seemed to make a difference when I ran into micro-bubbles.

Had a national cabinet mfg give me those tips and that's what they used.


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## DeanV (Apr 18, 2007)

It is pigmented. I followed the pds sheet for Ken aqua to try to fix it. It worked for the low gloss, but not the mid gloss.

I will need to get more scrap doors and see if I can replicate it or not. Started with hvlp, then tried airless. Airless was a little better with the Zenith pigmented.


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## yoursurfacepros (Feb 23, 2018)

Practice makes perfect :/. Its tough when you've been doing something for years and the product makes it difficult.


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## Mr Smith (Mar 11, 2016)

Geez, I just wrote about 1000 words and it vanished after bumping a key on my keyboard.

To sum up:

Air flow is super important. Add a fan to keep the flow going. The exhaust fan sucks everything out and the vacuum must be replaced with fresh air.

KA+ is worse than KA

Thin coats: Try spraying on a hanger to do both sides. I always get problems laying them flat with WB lacquer.

Use a pre-cat lacquer instead. (although I know you are all about WB)

If WB Lacquer: Add additional retarder (or anti-foaming agent) to the mix along with your Butyl Cellosolve.

Have you tried the original Sayerlack WB lacquer from Italy? Sherwin Williams bought that company and their version of Sayerlack is inferior. Some shops carry the original.

Has anyone used a semi-gloss paint like Aura on cabinets and finished it off with the "stays clear" from Benjamin Moore?


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## Center_line_Painting (Jun 4, 2017)

@Wolfgang 
Just to be clear, adding Denatured Alcohol along with butyl?
@Mr Smith ...excuse my ignorance, what kind of retarder or anti foaming agent are you suggesting?


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## Mr Smith (Mar 11, 2016)

Center_line_Painting said:


> @Wolfgang
> Just to be clear, adding Denatured Alcohol along with butyl?
> @Mr Smith ...excuse my ignorance, what kind of retarder or anti foaming agent are you suggesting?


Retarders for waterborne lacquer are alcohols such as butyl cellosolve or butyl carbitol. You can buy anti-foam additives at some paint stores. I can't remember the name. Laying it on too thick will always produce bubbles.


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## Center_line_Painting (Jun 4, 2017)

ahh. got it.


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## ThreeSistersPainting (Jan 7, 2017)

I suffer the same issues in my shop when it gets cold out, I still have a cabinet door I am waiting to clear coat. The colder and dryer it is outside, the more bubbles I get in my WB finishes. The top coat seems to tack up before the finish can lay out correctly.


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## CApainter (Jun 29, 2007)

I've had the micro bubbling occur with BM Advance. I tried everything to reduce the bubbling but it kept occurring. Then I realized I was picking up a lot of air in the paint during straining. I was using the typical strainer bags. So instead of lifting the bag way out of the bucket, I strained it close and slow at the material. It seemed to help in my case. RH% and ambient temps probably influence the bubbling.


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