# Frustrated with microbubbles, ?solvent pop



## jmcafee76 (Sep 21, 2020)

Problem with tiny craters and volcanoes which looks like solvent pop. Not seen in the wet finish. I don't see the application as too thick.

Spraying BM Advance, Fuji 4 stage HVLP, 1.8 mm air cap. 

Material thinned 10%, mixed with helical paddle. Strained through 190 micron filter.

Temp 70 degrees, humidity 45%.

I =think= this began after I added a drop of oil to the needle shaft to lube the packing nut (per Fuji recommendation), but the gun has been thoroughly cleaned with water and mineral spirits since then. No contamination in the air hose. Gun is dry and free of solvents when spraying.

Thanks for your help.


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## AngieM (Apr 13, 2016)

What about the substrate? 

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## jmcafee76 (Sep 21, 2020)

MDF cabinet door previously finished with oil enamel. Old finish sanded with 150, spot primed, and sanded again with 150.


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## AngieM (Apr 13, 2016)

Definitely looks like puberty acne to me. Cysts followed with pits. @NACE what do you think? 

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## finishesbykevyn (Apr 14, 2010)

What did you prime with? What is the surface your painting? Looks like classic fish eye.


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## NACE (May 16, 2008)

I suspect residual mineral spirits from cleaning gun caused fish eyes. I’ve been cleaning with acetone due to its high evaporation rate. Mineral spirts varies in purity and quality and can contain a lot of water or can be oily.


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## Wolfgang (Nov 16, 2008)

People have the misconception that all thinners, cleaners, and reducers are manufactured with the same purity. Obviously not. Even acetone has different purities. The box store acetones has been known to cause problems with different finishes when used as a thinning agent. Should be okay to use as a gun/hose cleaner though. I've seen it cause flash rusting on sheet metal when used as a wiping cleaner.


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## Redux (Oct 27, 2018)

Wolfgang said:


> People have the misconception that all thinners, cleaners, and reducers are manufactured with the same purity. Obviously not. Even acetone has different purities. The box store acetones has been known to cause problems with different finishes when used as a thinning agent. Should be okay to use as a gun/hose cleaner though. I've seen it cause flash rusting on sheet metal when used as a wiping cleaner.


Not all tap water is created equally either, and thinning with tap water can result in surface tension issues affecting to the finish’s wetting ability, sometimes resulting in fisheyes, as well as resin and pigment dispersion issues, all of which are pH sensitive. Well water can range from a pH in the low 5’s to over 8.5 and this is why many tech sheets state to thin with deionized water.


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## Wolfgang (Nov 16, 2008)

I know that when I was spraying AquaKem WB I was using distilled water, denatured alcohol and butyl acetate as reducers / retarders. The butyl also helped to eliminate pin holes.


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## store021 (Mar 27, 2017)

Did you wipe off the dust from sanding?
Have you tried spraying a slightly thicker coat (thicker than the first coat) or turned the pressure up at all?


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## Redux (Oct 27, 2018)

If you can’t determine the cause, you might consider changing your deodorant.

A floor finisher I’ve worked with would always get fisheyes in his floor coatings. He’d typically be hired to do the lower visibility floors and my company would do the higher visibility floors. The both of us would be using the same procedures & finishes and nobody could figure out why my finishes were fine and his weren’t. 

It turned out that the fisheyes in his work were due to his assistant’s deodorant. After not believing that was the cause, and after googling it, there were several references to deodorant being the root cause.


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## finishesbykevyn (Apr 14, 2010)

Redux said:


> If you can’t determine the cause, you might consider changing your deodorant.
> 
> A floor finisher I’ve worked with would always get fisheyes in his floor coatings. He’d typically be hired to do the lower visibility floors and my company would do the higher visibility floors. The both of us would be using the same procedures & finishes and nobody could figure out why my finishes were fine and his weren’t.
> 
> It turned out that the fisheyes in his work were due to his assistant’s deodorant. After not believing that was the cause, and after googling it, there were several references to deodorant being the root cause.


Just when I thought I had heard it all! :vs_lol:You never seaze to amaze me Redux..


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## finishesbykevyn (Apr 14, 2010)

The only time I've had any issues with Advance, is when the humidity was too low.. and, Also if your using a cup gun, the product gets sloshed around in the cup, thus causing bubbles prior to application. The bubbles can get transferred to the surface and dry before popping.(speaking from first hand experience)
Also, are you sure the fisheyes are not in the primer. Sometimes you cant see them untill topcoat goes on..


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## Redux (Oct 27, 2018)

finishesbykevyn said:


> Just when I thought I had heard it all! :vs_lol:You never seaze to amaze me Redux..


It’s a pretty common occurrence, more so than one might expect. I’ve seen members making mention of it @ woodworking and auto body painting forums. Apparently a lot of personal care products contain siloxanes which have a tendency to flake off, resulting in craters & fisheyes once they’ve come into contact with the surface being finished. 

The boss of the other flooring company I mentioned had his assistant bring in all of his personal care products, powdered nitrile gloves, booties, pretty much anything and everything that could have come into contact with the floors. They tested out all the above mentioned on some mock-ups and it turned out to be the deodorant which resulted in craters within the film. The boards tested with the deodorant looked like a piece of Swiss cheese.


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## Wolfgang (Nov 16, 2008)

There are some good water-based wipe down products out there. The auto refinish industry has been using them for years.

Also, check your tack rags. I've known some to cause reactions with finishes.


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## Joe67 (Aug 12, 2016)

Sorry but if it turns out that I can't paint while wearing deodorant, I'm moving on to plumbing.


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## Masterwork (Sep 13, 2020)

Joe67 said:


> Sorry but if it turns out that I can't paint while wearing deodorant, I'm moving on to plumbing.


No Zest soap. That's one I know of. The Toyota plant near me has an air shower you have to go through to get to the paint area. Alarm bells go off if it sniffs certain things on you.


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## canopainting (Feb 12, 2013)

Could be moisture droplets from respirator or sweat.


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## finishesbykevyn (Apr 14, 2010)

I honestly just don't think Advance should be sprayed from an HVLP. IT's designed to "flow out". When you apply it with air, it just drys way to fast entrapping air bubbles etc.. I spray it with my airless 308fflp and it;s flawless 99% of the time.


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## propainterJ (Jan 31, 2011)

The fish eyes are a contaminent,probably from those stupid tac rags,use a cotton rag from paint store gently wetted with appropriate solvent

The Pimples are maybe from paint drying too fast,or dust on surface,or on floor of shop getting pushed into air from your boots

Id try getting a wet mop and mopping down all around your spray area ,plus blowing off your ceiling and walls of your shop prior to paint

Just a thought good luck


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