I have been lucky, until now. Fish eyes in paint

[barracuda816]

Good evening gents (and ladies),

Up until now this is not something I have had trouble with. And I know I should be trying to find the culprit. But I am coming to the conclusion of a full respray on a classic restoration and am low on both time and the paint from this batch (I am not wanting to buy more, that will likely not match 100% and then I have to spray the whole car again).

I am using a 2k acrilic direct gloss, with a 2k epoxy primer. The last two panels have had tiny fish eye on them. I always wipe down the panels with a silicon remover and a tack rag before painting.

I have a bodged together compressor system, using one oiled and one oil less joined together that just about keeps up with the spaying and the fresh air fed mask. The airline runs though around 10 meters of copper 18mm pipe and into a desiccant drier followed by a filter and then a 2m drop with a drain. I never get any water in the post desiccant drier or the drop line.

I think I have somehow contamination in the line though. As I sprayed the topcoat directly on the primered panel (after the required flash time) and still had some tiny fish eyes. I will change the hose. But not sure what can be done to remove the contamination from the gun. I use gun wash as it's cheaper. Should I run a bit of the 2k thinners through?

I was thinking about using this https://www.mipa-paints.com/fileadmin/product/gb/pi/lm/Mipa_Anti-Silikon-Zusatz_EN.pdf as I quite rate the mipa stuff and its easier to find than the upol stuff here.

Has anyone experienced the fish eye eliminator type additives?

Or any other tips on this? Im not sure it could be anything other than coming out the gun if its happing even after wet on wetting the primer (that showed no fish eyes). Unless the silicon rises to the surface after primering?

Thanks, in advance. Luke

 

[ajlelectronics]

Has anyone experienced the fish eye eliminator type additives?

They are silicon and wreck the gun, don't even think about it. Cleaning should be slow panel wipe and then a very light Tak rag application with no pressure, immediately before spraying.

Bear in mind that the contamination could be from somewhere in the booth.

 

[ajlelectronics]

Should I run a bit of the 2k thinners through?

Always. You use the gunwash as a general solvent, but always clean with virgin thinners for the product you are using next.

 

[norsa]

No, don't use an additive, it only disperses the fish eyes into tinier fish eyes. It can then affect your next few paint jobs with that gun. I'm going to say it's unlikely you're getting contamination in the line if its just localised patches. More likely a substrate contaminant. I trust WD40 is not present in your spray area.
Nick

 

[barracuda816]

Thanks aj. The cleaning is exactly like that, those fish eye eliminators are Silikon

Do you know if the epoxy primer is unaffected by silicon? Or if it would encapsulate or rise to the top of the primer?

 

[ajlelectronics]

Thanks aj. The cleaning is exactly like that, those fish eye eliminators are Silikon

Do you know if the epoxy primer is unaffected by silicon? Or if it would encapsulate or rise to the top of the primer?

It would behave just like the colour coat if contaminated.

 

[barracuda816]

No, don't use an additive, it only disperses the fish eyes into tinier fish eyes. It can then affect your next few paint jobs with that gun. I'm going to say it's unlikely you're getting contamination in the line if its just localised patches. More likely a substrate contaminant. I trust WD40 is not present in your spray area.
Nick

Thanks nick, no wd40 anywhere.

It’s not localised, it’s just I have been paining it by panel due to time and space constraints.

 

[barracuda816]

It would behave just like the colour coat if contaminated.

Good to know, thanks. Must be something in the gun then, as the primer is problem free.

 

[norsa]

Umm. Sometimes, it doesn't show in the primer as it does in top coat but it's still there and can peep through.

 

[norsa]

Test panel would be my next move. Clean, tac, paint. See how that lays.

 

[mr haynes]

How did you mix paint?

 

[barracuda816]

Paint mix is in graduated mixing cups swilled out with thinners and put through a filter cone.

Thanks gents for the ideas. I have a bit of time today to do some tests today.

First things will be a rinse of the gun with 2k thinners. And maybe change out my airline for a spare.

Some one should invent some paper sheet that changes colour on contact with silicon. Would really help to do a dry test for the gun and airline set up.

 

[8ob]

The guy that comes in to do our paint wont use our airlines, he has his own filter and airline set up that he brings along.

Bob

 

[steveo3002]

any new spray on deodorant /smellys /hair gel etc?

 

[norsa]

If you're doing a test. Spray with the current set up. Then if there are no fish, you've instantly eliminated your equipment.

 

[ajlelectronics]

As my workshop is used as my spray booth, nothing is allowed in aerosol form bar panel wipes, solvents and paint.

 

[mr haynes]

There was a previous thread where the problem was introduced by using medical syringes to measure the paint.....

 

[barracuda816]

Little update. Tried cleaning brown the panel with a new panel wipe, no change. I then changed out the airline and fully cleaned the gun out with proper thinners (not the gun wash) and it seems to have cured it . I suspect it was the gun wash but not sure if it was the line, or if I’ll get problems again.

Thanks for all your assistance.