I NEED GOOD INFO. ON DC ARC BLOW BACK. HOW TO STOP IT? FROM KEVIN MCDONALD. MY SCHOOL IS FRANTIC.ITS STOPING THERE TESTING. AND I HAVE CALLED EVERY ONE I COULD THINK OF IN THE FEELD. THEY SAY THERE WORKING ON IT . THANKS ! P.S MY WEB SIGHT IS WWW.ALLIED WELDING SCHOOL.ORG ANY HELP WOULD BE GREAT!