New paint on my wipers arms crackling - WTF?

[Jand3rson]

I've got the wiper arms pulled off of my car, and I cleaned them up and painted them with Satin black Rustoleum. After they dried, I noticed there was a spot on each one that had a run in it, so I sanded it down and sprayed some more paint on. The spots I sanded down and sprayed another coat on are almost immediatley developing a crackle finish, just like that paint you can by that does the same thing. Why is it doing that? I'm going to have to wait until tomorrow when they dry and sand it off and do it again, but why is it doing it in the first place?

This was taken not 5 minutes after this coat:

[Rocla]

How long did you let it dry before sanding?

Usually paint instruction tell you to shoot second coat with in 15 minutes, or after few days, after paint has completely dried.

[Jand3rson]

How long did you let it dry before sanding?

Usually paint instruction tell you to shoot second coat with in 15 minutes, or after few days, after paint has completely dried.

Probably not long enough, a couple of hours. It was also a little bit cold in the garage. I'll sand it down tomorrow and resrpay. I think I just got impatient.

[StereoInstaller1]

Josh, that is a chemical reaction between the last paint and this paint, or a reaction form whatever you cleaned with before painting.

There is a small chance of that being caused by "outgassing" of the first coat...but it ususally does not look like that, but more "spotty".

What temperature are you painting at? Bend should be cold as hell these days. 70 degrees or better!

Luke

[Jand3rson]

Josh, that is a chemical reaction between the last paint and this paint, or a reaction form whatever you cleaned with before painting.

There is a small chance of that being caused by "outgassing" of the first coat...but it ususally does not look like that, but more "spotty".

What temperature are you painting at? Bend should be cold as hell these days. 70 degrees or better!

Luke

Not very warm here. I'm painting in the garage, but I think when I sprayed that coat that crackled, it was starting to get too cold in there. It's fine during the day, but this was around 9pm, too cold in the garage for paint. And you're probably right about the 2 coats reacting, I don't think I let it dry long enough before I tagged it again.

[StereoInstaller1]

Not very warm here.

If your nipples are stiff, don't paint!

Bwaahahaa!
Luke

[AndrewBird]

Rustoleum doesn't do that normally, even if you put the second coat on too soon. My guess is the Rustoleum is eating away the original paint. I would just try sanding them back down and respraying. Make sure you clean off all the sanding dust first though. And like Luke said, cold is not good. You can get away with spraying in a cold area if you bring the painted pieces into someplace warmer.

You should pickup a small heater for the garage. Ones like this:



Work great. They don't use much electricity and they don't get hot enough to burn you. We used one in the shop for a long time before it finally died.

[Van Westervelt]

I think it has to do with the reaction from the two different paints. When y ou sanded it, you probably just sanded down to a fresh laer of the old paint which was more reactive than the outside area.

[ivo316]

He's right, strip all the old paint, it has happened to me.

[euroshark]

What did you prep them with? Everything that I have ever prepped with sandpaper or steel wool, I give it a very thorough wipe down with laquer thinner. If you paint over oil or grease, or like they said, other chemicals you might get bad adheision.

[BahnE30]

it's the original factory paint reacting with whatever your spraying, sand down to bare metal and spray away, or get different paint....