Duct, Metal and Sheet Work Fabrication. Aluminum, Stainless Steel, Galvanized, & Black Iron. Residential-Commercial-Marine. Computer Aided Plasma Cutting Ability. 26 Gage - 1/4" Plate. New to the industry in name only, Duct-Fab Inc has extensive knowledge of designing and fabricating HVAC ductwork systems for all types of applications. We keep up with the latest info from SMACNA, NPFPA, PBCCI, USCG, SOLAS & ABS.