We can now offer our sheet metal customers an alternative end connector designed to strengthen the duct wall and connect duct sections together. This system is easy to work with either on the job or in your shop. Manufactured from 20-gauge steel we will be stocking the 12ft lengths. The flange angle is furnished with an integrated sealant pocket for a secure air tight fit. You simply cut the flange angle to the proper length using a wooden mallet insert the corners into the flange. Starting at a corner, use a mallet hammer the completed frame into the raw edge of the duct section. Moving in one direction, make sure the duct is seated into the mastic. The frame can be fastened to the ductwork with either hex tex screws (10x3/4”) or spot welds. . When you get ready to hang the duct simply apply a 2 to 3” strips of gasket on the 4 exposed corners of one frame. Starting at the center of the other mating frame, apply a single strip of gasket completely around the inside edge of the frame. The butyl gasket is a permanently soft caulking compound with a high percentage of virgin butyl rubber. Butyl gasket can withstand movement without cracking and will adhere to most clean dry surfaces such as steel and has a temperature range -40to 200 deg. The next step is to mate the two ducts being installed together and snap a 6” piece of metal cleat on each side of the frame as per the manufactures spacing recommendations. Install the corner bolts, you now have a sealed duct joint. DOMJ is designed use on larger size duct and has many applications including large commercial and high-pressure applications.
