Fish eyes

[wristpin]

Wanted to tidy up the rather scabby cowling on a small engine that I've gotg just overhauled . Stripped it back to bare metal, wiped it over with solvent and sprayed it with Upol etching primer from a rattle can - went on fine.
Left it for 24 hours and sprayed it with Farmline gloss from a rattle can and one section "fish eyed" badly while the majority was fine. Nothing had been used or done in the shed where it was between the primer and top coat so wondering why?
If the cowling had been previously contaminated is there any logic to the primer going on OK and the top coat reacting , but only in one place?

 

[ford34/2]

Fish eye is most often caused by a spot of oil, grease or wax on the surface. The best way to prevent it is to clean the surface well before painting, even silicone in the air. Been there --even got the tee shirt
If you spot a fish eye in your finish Stop your work. Let the paint dry as is for at least 24 hours.

Sand the surface with #400 or finer grit sandpaper until the fish eye is gone and the primer coat appears. Clean the surface well with alcohol and begin the painting process again.
The best method to counter this is to pre-clean the surface well before you begin. This will stop it before it starts.

Despite some of my best efforts, my spray booth is the garage and air turbulence can dislodge other minute bits and bobs of all sorts from previous work, A lot of this stuff you cant even see in the air. Be scrupulous with your clothing with preparation and protect the surface till the spray gun hits it.

Stan

 

[norsa]

Fish eye is the most irritating paint issue because it could come from absolutely anywhere. From your description, it has to be under the primer coat and often doesn't show its self until colour coat. you should in the ideal world have used panel wipe before you sprayed and immediately wiped it off before it flashed off, then tack cloth and away you go but sometimes seems overkill for just a little panel. You were unlucky that's all. Guide coat it and see if you can flat all the fish out then make that area your first pass. It will react pretty much straight away if still present.
Nick

 

[wristpin]

Thanks for all the advice - I will put it into action tomorrow and get some panel wipe for next time.