Yet another primer question from my side.

Lets say your prepping a fender and doing your final sanding of your 2k primer, base is next. Your done sanding but you have one or two burn troughs on an edge or some other defect that needs primer.

Would you just fill in the defect spots with more primer and sand or would you primer the whole fender?

On a side note, say your spraying a light metallic waterborne, prepping a fender, which grit would final sand with before 2k primer? No sealer, just 2k then base.

Just spot in the burn throughs and sand.

For a light metallic I like to sand the primer with P800 wet. If you're dry sanding then P500 on an RO is ok, too. Anything coarser than these can result in sanding scratches showing through. For a solid colour P600 wet or P400 dry on an RO.

Thanks. I will spot in then.

I was thinking which grit when final sanding the substrate before 2k primer?

My apologies, I misunderstood.

If you're using a filler/primer then not coarser than P180 and not finer than P400 (all dry). I like to finish repairs with P240 on a RO and extend the surrounding area with P400, again on the RO. If it's just a primer or a primer that you're using as a sealer then P400 (preferred) to P600.

Thanks for the tip. Im starting to get closer to having ok standard quality in my work without making backwards steps all the time. Which is much thanks to your advice and this forum.

Help me understand this.
I had what i thought was a leveling issue in the primer, same as in the pic and so i sprayed some more primer but after sading it looks like this. Im having a hard time understanding what im looking at and what to with the "circles/transitions". Should i spray more primer, sand, base over?

When i sprayed the affected area i just sprayed that area moving a bit further out on every coat.

I cant feel any transitions and the reflection is good when wet checking

Looks like you've sanded through.

Re-prime, sand without going through, base and clear.

Don't change your gun distance. Stay at one distance to give even wet coats. Pulling back will only give you an uneven finish that needs more sanding.