Can I use WD-40 to lube my airbrush?

A: No!  Don't!  Bad Idea!  Just say no to WD-40!

In-Depth

WD-40 and paint basically don't mix.  They really don't like each other.

In fact, there are some paint shops that will string you up for even bringing a can of the stuff into their shop. 

Here's why.

• When you lube up the needle it will come into contact with the paint.
  
  That lube then mixes with your paint as you  move the needle back and forth.  
• When you lube the air system some of the lube will travel with the air to be mixed in with the paint.
  
  This isn't as big of a problem as WD-40 on the needle, but it's enough to ruin a great paint job.

Basically the lube mixes with the paint and causes something called fish-eye. It's a rather annoying and persistent problem.  Which is why car painters go postal on people who bring the stuff in.