Refrigeration and Air Conditioning

From EPE magazine

Online tutorial from Media College

From the Electronics Club

Contains tutorials for MIG, TIG and ARC welding, plus information on welding different types of steel.

From Safework Australia

Guide for welding and cutting from BOC

SMACNA's technical manuals and standards relate to the sheet metal and HVAC industries. The site contains free materials, as well as ones that need to be purchased.