Paint bleed under tape

What kind of masking tape are you using?  Are you airbrushing straight down onto the edge and not pointing the airbrush directly at it?  Do light, thin passes with the airbrush, and don't point straight at the masking edge so the paint doesn't build up along it.

I'm using Tamiya vinyl tape and their masking sheets without getting paint bleed under the edges.

Easy fix.

After you've masked, apply a layer of clear coat and let dry...then paint as usual.

It seals the edge and virtually eliminates 'creep' under your tape.

As far as removing the blotches, delicate scraping with just the tip of a hobby knife works about half the time. With Tamiya (or any) acrylics, remove your masking as soon as possible...preferably when 'set' but not completely cured. You'll get a much cleaner edge with less chance of flaking...and removing 'errors' will be easier, before it's fully bonded to the layer below.

Using Tamiya tape. 

Used thin coats but not necessarily straight down.

The suggestions here sound good, will try them.

Thanks.

gregbale

Easy fix.

After you've masked, apply a layer of clear coat and let dry...then paint as usual.

It seals the edge and virtually eliminates 'creep' under your tape.

As far as removing the blotches, delicate scraping with just the tip of a hobby knife works about half the time. With Tamiya (or any) acrylics, remove your masking as soon as possible...preferably when 'set' but not completely cured. You'll get a much cleaner edge with less chance of flaking...and removing 'errors' will be easier, before it's fully bonded to the layer below.

 

You can also seal the tape edges by spraying the color you are masking over.  Just spray a light coat over the tape edges.

I have also had fair luck with scraping areas with knife and light sanding with very fine sandpaper, 1000 or 2000.