Metal Primers

When working with a metal primer, also known as etching primer, try to avoid getting it onto plastics. It may cause undesired reactions like adding a texture to the plastic but shouldn’t cause any damage.

Primers like Mr Hobby’s Mr Metal Primer are self leveling like if you were using Mr Color Leveling thinner, so you don’t really need to fuss with it too much even when brushed.

The bottled variant will last a lot longer than you’d think. I would recommend using disposable brushes if you don’t want to deal with cleaning it up, but a bit of lacquer thinner should work fine.

Finally, let it sit for at least a full 24 hours before trying to paint, this is related to the above undesired reactions with a paint going on top when it hasn’t fully cured.