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brimcp99 02-28-2011 07:24 PM

Tiny tiny solvent pop?
Hey guys, ive got a weird problem, I can hopefully explain well enough in text. Ive been painting cars for a while so am reasonably sure its not a run of the mill issue.

Basically in some circumstances when I paint I get these tiny tiny specs in my paint. They are in a uniform pattern all over the panel and cover every square inch, Im 99.9% sure its not dust. Trust me I unfortunately know all to well what dust looks like stuck in paint. :rolleyes:

They are not visible enough to be of real concern; but are bugging me because I know they are there. You can only see them when looking very closley at the right angle with fluorescent lighting. It only happens 1/20 when I paint, im not sure what factors have changed to cause it.

I do wet the booth before painting and last time it happened im reasonably sure it was a hot day, but canít remember exactly as I only noticed them weeks latter. Im thinking that itís some type of reaction but am at a loss so far.

Any thoughts?

panelwagon62 02-28-2011 08:38 PM

What tip do you use in your gun?

Runnin'OnEmpty 02-28-2011 08:58 PM

This is not a waterbased basecoat is it?

And it's not being machine shaken?

dinger 02-28-2011 09:41 PM

I had the same problem, I was told I didn't wait long enough between coats. The first day the paint looked perfect, as days went by, it got worse. Ended up color sanding and re-shooting the clear. 2 stage HOK paint, water based.

Lizer 02-28-2011 10:55 PM

Do you have an inline filter on your air hose to remove water? Do you know what fish eyes are and does it look like that to you?

milo 02-28-2011 11:25 PM

Is the compressor in the same room your painting in?

brimcp99 03-01-2011 01:54 AM

Im using a 1.4 tip on a gravity feed gun (non-hvlp), shotting a single stage 2k urethane. Compressor is out of the booth. I have a water trap after a copper tube that flows through a tub of water for cooling.

Im reasonably sure its not fish eyes, it basically looks like really really really fine sand has been applied all over and is trapped underneath, I did some very fine wet sanding after marking an area and they are definately tiny nibs.

However I can almost say 100% that its some type of paint problem rather than fine debris getting caught up in the paint, it is much to uniform and even to be dust.

At first i thought it may be the foam in the compressor air intake breaking up into tiny particles then flowing out through my airline, but ive changed setups and it still sometimes happens. Ive got a gut feeling it may be a humidity issue but am not really sure

jcclark 03-01-2011 05:57 AM

If it's that tiny, it probably can pass through your strainers????
If so, it could be old activator or even specs of paint.
I had flattener go bad and do just that.
It was like super fine sand.
Went right through my finest strainers.
Keep us posted, I'd like to hear what you find. :pimp:

302 Z28 03-01-2011 06:51 AM

I agree it's got to be a product issue, something your using has gone bad.


oldschool hero 03-01-2011 07:02 AM

It is possible that static electricity could be a problem if humidity level is low.
I ground the car to the floor and also use a wire connected to the spray gun to the compressor.Some may say thats bunk but it's also good insurance. :cool:

brimcp99 03-01-2011 02:20 PM

I donít think its a paint problem, well chemically atleast, because I painted the other side of the ute a few days later and it came out fine with the exact same products.

Here is a photo of what I am talking about, it covers the entire panel, itís just that its only visible in the section with the fluorescent light on it.

Its annoying because the paint laid down real smooth so wouldnít have had to wetsand otherwise, the panel looks fine out in the sun, but just under booth lights you can see the issue, the below door is the same one as the first photo from a different angle.

Runnin'OnEmpty 03-01-2011 02:36 PM

After seeing the pics, it certainly looks like solvent pop.

brimcp99 03-01-2011 04:57 PM

Oh really? When ever ive had it before its been bigger and more of a liitle crater than a nib, thanks.

Runnin'OnEmpty 03-01-2011 08:30 PM


Originally Posted by brimcp99
Oh really? When ever ive had it before its been bigger and more of a liitle crater than a nib, thanks.

Well now that you mention it, solvent pop does form craters.
Are you saying these nibs are on the very top surface of the paint?

Maybe try looking at it using a strong shop light and a magnifying
glass...? See if the nibs are actual particles like dust, or bubbles
in the paint film...

Derkyb 03-01-2011 08:34 PM

nope its moisture in your lines! I just had the exact same problem last week and the only thing that solved it was buying a refrigerated dryer for the compressor from harbor freight for 400. How far away is your compressor from your supply? do you have a see through dessicant filter at the gun? I cant remember where I read the thread from barry but he said that stuff that looks like sand is actually the iso's crystalizing due to the moisture or something like that but the dryer definitely solved it. :sweat: Oh and It wont matter how many filters and water separators you have it will only slow it down but will still be there, trust me I had three dryer filters and a separator and still got water at the gun.

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