Question how much old paint do I need to remove for spray painting?

[ArchLuke]

How much of the old powder coating do I need to remove before applying a primer?

 

[Lutfij]

If you really want a good paint job, strip the paint down the bare metal. From there wipe clean of any dirt/grime with a tack clothe, then apply an even coat of primer. Then use fine grit sandpaper like 800 or higher, wet sand and then wipe clean with tack clothe and then apply base coat>top coat.

^ That's my way of going about with a paint job. Others would also suggest scuffing the surface until thoroughly scuffed then apply primer. Depends on how good of a paint job you want to perform on the case/paint job.