# How do I stop an HVLP gun from spraying specs on everything?



## Greasy_joe (Aug 3, 2021)

I work as a sign painter and fabricator, and by all means out paint jobs aren't perfect and don't need to be. But lately, after I got a high flow fitting for the end of the hose and the gun, the gun has been spraying specs of paint. I've tried changing every gun setting imaginable. Do I need high flow fittings on everything for them to work? (On the other end of the hose, regulator, etc) Could it be a humidity or heat issue? Please help, I'm fairly new to painting. Thanks.


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## finishesbykevyn (Apr 14, 2010)

What product are you spraying? Are you straining your paint? Kind of looks like air bubbles. Is there low humidity right now? Could be a lot of things..


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## Greasy_joe (Aug 3, 2021)

finishesbykevyn said:


> What product are you spraying? Are you straining your paint? Kind of looks like air bubbles. Is there low humidity right now? Could be a lot of things..


We use Matthews Acrylic Polyurethane paint, and I strain everything that goes into the gun. There has actually been a drought lately, but it's been raining a lot lately and the problem has persisted.


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## finishesbykevyn (Apr 14, 2010)

Not sure what set up you are using but here is the tds for your product. Maybe it can help.. Like others have mentioned, your tip/needle size may be too big. or too much air.


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## CApainter (Jun 29, 2007)

What type of compressor are you using? Does your compressor have an inline water separator.? It looks like moisture is affecting the coating.


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## Holland (Feb 18, 2011)

Is it a multi-purpose shop? Looks like sawdust contamination.


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## Greasy_joe (Aug 3, 2021)

CApainter said:


> What type of compressor are you using? Does your compressor have an inline water separator.? It looks like moisture is affecting the coating.


We have a Quincy air compressor, I'm not sure if it has a water separator built it but I have a water separator just before the regulator.


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## Greasy_joe (Aug 3, 2021)

Holland said:


> Is it a multi-purpose shop? Looks like sawdust contamination.


Yes, we do everything in one shop. So things like the CNC router and sanding metal don't help. I am in a paint booth though, and the issue I'm having hasn't always been a problem even though there's always been dust.


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## Greasy_joe (Aug 3, 2021)

finishesbykevyn said:


> Not sure what set up you are using but here is the tds for your product. Maybe it can help.. Like others have mentioned, your tip/needle size may be too big. or too much air.


I have an Annest Iwata LS-400 gun. I've tried messing with the air pressure on the regulator but everywhere from 40 to 80 psi has the same problem. Why would having a needle that's too big cause this problem? Are the tip and the needle separate things? Is there a specific size I would be looking for for the smaller needle?

Sorry for all the questions but I know very little about painting.


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## CApainter (Jun 29, 2007)

Greasy_joe said:


> We have a Quincy air compressor, I'm not sure if it has a water separator built it but I have a water separator just before the regulator.


I'm assuming you drain the compressor tank, unless it has an auto purge. Humid air sucked into the intake will condense and create a lot of water in the tank. I know this from experience. I just changed out a compressor because no one drained the tank at the petcock for over twenty years.


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## Greasy_joe (Aug 3, 2021)

Greasy_joe said:


> I have an Annest Iwata LS-400 gun. I've tried messing with the air pressure on the regulator but everywhere from 40 to 80 psi has the same problem. Why would having a needle that's too big cause this problem? Are the tip and the needle separate things? Is there a specific size I would be looking for for the smaller needle?
> 
> Sorry for all the questions but I know very little about painting.


Having a lower PSI looks better, but isn't consistent. The bubbles (what I'm assuming they are) also only appear when the piece I'm painting is parallel with the ground.


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## Greasy_joe (Aug 3, 2021)

CApainter said:


> I'm assuming you drain the compressor tank, unless it has an auto purge. Humid air sucked into the intake will condense and create a lot of water in the tank. I know this from experience. I just changed out a compressor because no one drained the tank at the petcock for over twenty years.


I will try that, thank you*.*


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## Greasy_joe (Aug 3, 2021)

CApainter said:


> I'm assuming you drain the compressor tank, unless it has an auto purge. Humid air sucked into the intake will condense and create a lot of water in the tank. I know this from experience. I just changed out a compressor because no one drained the tank at the petcock for over twenty years.


We do purge the tank every few days, as well as drain any water from the lines and separators. Doing it again hasn't helped.


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## CApainter (Jun 29, 2007)

From what I read in the product TDS, the coating is a conversion coating with a part A and B? Obviously, the ratios would be a problem if they were off. So, if by process of elimination, it is not a moisture problem, a dust problem, or a ratio problem, it may be that the coating was applied too thick and entrapped solvents resulting in micro gas release. It's hard to see what the defects actually are from the photo. It actually looks like dust and debris blown on to the surface during spraying. But that was eliminated as a potential cause.

Was any one working on the rafters, or the roof where pounding could have dislodged debris?


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## Redux (Oct 27, 2018)

Could be CO2 gassing due to moisture in the air line…try using an in-line desiccant air dryer filter…


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