Most full-time art teachers are credentialed. It pays to go the extra mile to
get the credential because of the salary and benefits. Teachers working
without credentials are required to be in a credential program if they are
teaching. I worked 3/4 time as an art consultant in the elementary schools
for two years (California). They kept me under full-time because they
couldn't afford to pay out the benefits. I realized I was putting in as much
time as a full-timer without the benefits. So I went back to school. You can
find accellerated programs to get it done quickly.