Painting rims primer cracking

Posted by C2hype@reddit | projectcar | View on Reddit | 14 comments

Painting my wheels. Just applied a 4th layer of primer and seeing this cracking. Will it show through base coat and clear coat? Do I need to sand and reapply primer? 1 & 2 coat of primer used Rustoleum Fast Dry Primer (white) 3 & 4 coat of primer used Rustoleum Automotive Primer (black)

Reply to Post

14 Comments

[-]

toold-Tim@reddit

Looks like you missed a spot cleaning. Any solvent or cleaning agent not fully removed will cause adhesion to fail, so yes Unfortunately you will need to sand, clean, (both front and back) reseal, reprime, and then you should be back on track. Probably what happened is the back of the wheel wasn't fully clean or dried from solvent

[-]

Vollen595@reddit

Solvent pop.

[-]

NoMoOmentumMan@reddit

Where are you painting, what is the temperature?

[-]

C2hype@reddit (OP)

I was working in my garage with the door open. I’d say temp was around 50 degrees

[-]

NoMoOmentumMan@reddit

Assuming you cleaned and prepped the surface properly, that's likely your problem. Spraying paint gets really difficult the colder (or hotter) it gets. 65ish-75ish is the sweet spot.

[-]

C2hype@reddit (OP)

Would it be best to hit the wheel with a heat gun after each coat?

[-]

HSLB66@reddit

Very light heat can help cure but you have to keep it even. Not recommended because it’s hard to do with a gun

[-]

NoMoOmentumMan@reddit

Not likely. the whole space, wheel, and paint need to have the same stable temp. I saw in another comment thst this was with a thicker coat of paint, which makes sense. Paint is flashing off at different rates in different areas.

[-]

MyNamesMikeD75@reddit

It absolutely will show, you have to strip and reclean it

[-]

Material-Job-1928@reddit

I have seen two things cause this. Poor surface prep, either too smooth, or some chemical left on it, or the next layer applied too fast. The first layer was dry, not cured, and the solvents in the next coat caused the paint to flake. Sand it, scuff it, and shoot it again with more time between layers. You might try baking the paint a little. I painted some markings on, something, and the enamel I used to fill the lines is almost more durable than phosphate the factory put on the rest of it. I did 300F for 15 minutes.

[-]

AKA_Squanchy@reddit

Too cold. Also what did you sand with for prep? If you were down to metal were you using 120 grit? If paint then 400 or 600. The primer needs some tooth.

[-]

YousureWannaknow@reddit

Probably it will... I bet it might be related to speed of drying or reactions with chemicals you've used during preparation. Was it thick layer?

[-]

C2hype@reddit (OP)

Yea came after the thick layer

[-]

YousureWannaknow@reddit

Grind it down and start again with thinner one. No other way, sadly