What causes "Orange Peel" In Car paint?

My stepson just spend a bundle, having his old jeep repaineted. On first glance, the paint job looked nice (one good thing about jeeps, they change little from year to year). Anyway, he was PO’d-becuase the paint has an orange-peel appearence -littel pores in the surface, instead of being smooth. What causes this? poor quality paint? Too-fast drying?

IANA Body Shop Guy, but my understanding is that it’s caused by the surface tension of the paint as it dries, and is mostly a result of laying the paint down too thick. I had a body guy tell me once that even a hack can do an orange-peel-free paint job, as long as he’s willing to wet-sand the heck out of each coat after he lays it down. Good painters can lay a thin even coat down so they don’t have to do much sanding. Lazy painters will just cover the car, let it all orange-peel up, then clear it and call it good.

Also, I understand that the new, low-VOC water based paints are much much more prone to orange peel than the ‘good stuff’ from a few years back.

Some level of orange peel is an unfortunate characteristic of urethane-based paints. The older lacquers didn’t have nearly as much problem with this.

Look sideways at even a brand new, fresh from the factory car, and you’ll see the paint is lumpy. Car restorers get a lot of heartburn over this as lacquer could easily be brought to a mirror-smooth finish, but getting urethane smooth takes a huge investment in labor.

Really bad orange peel is generally caused by drying too fast - either the paint was laid down too thinly or the paint booth was too warm. Oddly enough, being laid on too thick, or the room being too cold can also cause orange peel.

Finally a question I can answer from professional experience painting boats without a spray booth.

What you are describing is not “orange peel”. Orange peel looks like,well,like orange peel and a catch all term for amateurs to describe poor paint jobs.

What you have is either solvent popping or more likely fine dust settling on the jeep during the painting process.

Here’s an excellent cite describing and explaining your stepson’s problem as well as providing solutions.

I might add the he should start with an aggressive cut polish if the pores are a result of fine dust.

I repair and restore antique brass lamps and some other brass or bronze odds and ends. Spraying lacquer was the hardest thing to learn and I still screw stuff up all the time and have to redo it.

I’ve had problems with:
-too much lacquer
-too little lacquer

each caused by too much or too little pressure on the trigger

-spraying with the nozzle too close
-too warm
-too cold
-high humidity is a real killer
-too much or too little air pressure vs. how much fluid being sprayed
-poor mixing of the ingredients
-dust

in other words spraying paint or lacquer is more art and lots and lots and lots of practice than anything.