I have some confusion over painting over factory primer / basecoat I’m hoping someone can clarify. For the most predictable quality results it seems the best thing to do is sand down to bare metal then new primer, base, & clear coat. Thats the type of repair some shops will warranty for life. You are also paying multiple times over what a spot repair or what a repair would cost not removing all the factory primer & base coat.

However, realistically, let’s say you are doing a small repair where financially that isn’t an affordable option in a daily driver. Can you successfully just sand to basecoat & apply more basecoat over that than clear coat? I know that wouldn’t be a repair a shop would give a lifetime or even a 10 year warranty on.

But, people are doing these spot repairs / partial layer repairs with some success & they can look pretty good to the average eye. I don’t see a lot of guys on YouTube sanding down to bare metal to repaint a panel & they are blending adjoining panels not sanding them down to bare metal.

So, I’m wondering… Can you sand to factory primer & apply new base & clear over that? Do you always have to re-prime? Can you sand off the clear, apply new base coat until consistent then new clear over that? Is that considered a decent repair?

I’m assuming it’s not recommended to sand off clear & apply new clear coat only (say spot clear coat failure & base coat is pretty good) simply because it may not fill all the scratches in the basecoat from sanding? But, what about adding a few layers of basecoat over sanded factory basecoat - then clear coat. Is that acceptable or way hacky?

I believe there is a window when new primer / base is sprayed that it’s best to spray over it. Once it ages (and whatever is on top is removed from sanding) - can topping the old with new significantly effect durability? Assuming all sanding & prep is that acceptable for a repair for the average eye on a daily driver?

I know the standard professional body tech response is all those YouTube body shop guys are hacks & doing shoddy work. But I’ve seen some spot type repairs in person the average eye won’t see. I’m looking for pro opinions…

Can you sand & spray new layers over old (taking blending out of the equation & color matching) & expect a durable repair using quality products & 2k clear? By durable I’m not saying 20 years - I’m saying a few years worse case scenario, but the cost is < 1/4 repainting an entire panel that has been sanded to bare metal. So, maybe in a few years it will need to be redone - or maybe the car is gone. Or maybe it still looks pretty good?