Is it possible to paint over base coat ?
I have a little bit of surface rust on my fender corners where the headlight goes in. I'm going to send that down and prime that area but can I spray base over the existing base? If so what should I send it down to 400?

Are you spraying over freshly sprayed base coat?

'68 Coronet R/T wrote:Are you spraying over freshly sprayed base coat?

No its not fresh, I had someone paint my bumper which he did a horrible job, and I had to redo that.
Anyway I thought it was a good idea at the time because I had a few rock chips on my hood to have him redo the hood . Rock chips are back and also the clear he used is peeling.
I want the paint to last but I don't want to spend the time of a showroom car on it. Can I sand it down 220,320,400 shoot it with base and clear it.

https://photos.app.goo.gl/C5Knjifk3qMgXigp6

No. P400 is too coarse to go under basecoat.

Sand the bar back with P180 then refine that to P400 on a DA. Apply primer and when the primer is dry, block that back with P800 wet or P500 dry before spraying metallic or pearl basecoat. If the colour is a solid you can use P600 wet for slightly faster levelling.

NFT5 wrote:No. P400 is too coarse to go under basecoat.

Sand the bar back with P180 then refine that to P400 on a DA. Apply primer and when the primer is dry, block that back with P800 wet or P500 dry before spraying metallic or pearl basecoat. If the colour is a solid you can use P600 wet for slightly faster levelling.

Okay so I have a question why 600 wet not dry? Does wet vs dry give you a different finish?

Yes. Because the water keeps the paper cleaner it cuts more. So P800 wet is roughly equivalent to P500 dry.

NFT5 wrote:Yes. Because the water keeps the paper cleaner it cuts more. So P800 wet is roughly equivalent to P500 dry.

Ok great. When you say apply primer, since I'm going over the base where am I priming? Only where the metal is showing ?

Tell you what I'll do. I'm doing one right now and I'll take a picture of each step and post up with an explanation. Will take a few hours....

Here's where I'm up to right now. Repair done and repair area sanded with P180 on block, then refined with P240 on DA with P400 extending the edges and softening the feathering. Outlining for masking mostly done.

Nice I appreciate that that would be a lot of help.
I just have one last question for this second I'm a bit confused. I have my bumper epoxy primed, filled in some body work. Did like you did 180-240 and 400.

What's confusing me is I have to reshoot the epoxy and spray base while it's wet within 1 hour but but the prep sheet for the epoxy says sand to 240 before I apply epoxy. The base coat tech sheet says 400 so can I do 400 on the epoxy right now before I reshoot it and then base it or should I do 240 on the epoxy shoot it and base it like that

Is your body work good enough to just paint over or do you need to use the filling properties of a primer.

If the former, then just mix epoxy as a sealer, spray it out and then base straight over within the 1 hour timeframe. If the latter then mix epoxy at full strength and allow to dry before sanding with P800. Don't use P400 under base - you will see the scratches.