Strange paint issue

[AirSpeed]

I painted my Jet boat yesterday and it looked great, went to check it out this morning and found these odd patches all over. I used urethane paint, sprayed three coats and all was well. I painted in a booth I bought at harbor freight, kept it at 65 degrees all night. I don’t know if it will sand and polish, will try tomorrow but if I have to re spray it I don’t want this to happen again! Anyone have any idea what could have caused this?

[Corts60]

It seems maybe something was gassing off under the paint?

[AirSpeed]

Originally Posted by Corts60

It seems maybe something was gassing off under the paint?

It does, they’re thousands of tiny bubbles, I just sanded a spot and they’re hollow, I’m going to sand it down tomorrow and try again.

[mongocanfly]

How much time between coats did you give it?...what does the pds say?
The paint I'm using says 15min minimum between coats

[AirSpeed]

Originally Posted by mongocanfly

How much time between coats did you give it?...what does the pds say?

About 20 minutes, supposed to be 15 but it was only about 65 degrees yesterday so I gave it an extra 5. Ive never had this issue before. My only guess is I put it on too thick, I had a couple runs and they looked like foam. I’m thinking it’s solvent pop, gonna sand it down until I see no more bubbles then sand the entire boat, give it a day to gas off then spray again.

[MP&C]

Urethane is the most finicky paint on flash times to eliminate solvent pop. I think the extra 5 should have been double the 15.. Temperature changes, insufficient air flow, all will alter your flash times.

[AirSpeed]

Originally Posted by MP&C

Urethane is the most finicky paint on flash times to eliminate solvent pop. I think the extra 5 should have been double the 15.. Temperature changes, insufficient air flow, all will alter your flash times.

I’m gonna give it a half hour when I repaint. Going to sand until I see no sign of bubbles and try two more coats, maybe one if it covers well. It’s only about 15% of the boat that got the solvent pop, still going to sand the whole thing down, at least through the last coat. I’ve painted a lot of stuff but this is the first time this happened! Going to be more careful in the future!

[lupo]

Urethane's need humidity and heat to dry. Most paint calculations are based on 70° and 50% humidity. If it was a low humidity day and you recoated too quickly or applied the paint to heavy bubbling will be the result. When the top dries before the bottom layers and bottom layers emit gas causing bubbling in the surface. So slow it down watch the humidity and heat and don't lay it on so heavy.I hope this helps

[AirSpeed]

Originally Posted by lupo

Urethane's need humidity and heat to dry. Most paint calculations are based on 70° and 50% humidity. If it was a low humidity day and you recoated too quickly or applied the paint to heavy bubbling will be the result. When the top dries before the bottom layers and bottom layers emit gas causing bubbling in the surface. So slow it down watch the humidity and heat and don't lay it on so heavy.I hope this helps

Thanks! I will keep all that in mind!

[nsb29]

What temp reducer are you using? looks like You need to use a slower reducer to me

[AirSpeed]

Had much better luck with paint yesterday, listened to advice and it made a big difference. Thanks!

[AirSpeed]

I got it fixed, turned out pretty good!

[notsolo]

Turned out great. Did you end up mixing your own paint? and does it now match the truck?

[AirSpeed]

Originally Posted by notsolo

Turned out great. Did you end up mixing your own paint? and does it now match the truck?

I have a friend at NAPA, we matched it as close as we could

[Skymortar]

Five degree rule. Paint is based off a seventy degree ideal spray temp for medium reducer and hardener. For every five degrees under seventy you double flash time. For every five degrees over you cut it in half. Put your first coat on a little skinny. Not dry but not with the same build you want on your second coat. You want the booth running as long as possible. If you turn off the booth the solvents will come out of the clear and lay back down on the clear.