Rectangular Ductwork is typically insulated internally with Duct Liner rather than externally with Duct Wrap because of the acoustical benefits. Most duct shops will have two pinspotters for use in securing the Duct Liner to the Metal ductwork: a free standing “FG” model with a 5 ft throat and a smaller “MF” model with a 12 ft Cable and weld gun. Shops will favor the free standing Model for straight duct and the compact model for fittings in which a 12 ft cable is the only feasible method to weld the pins through the Liner into the steel ductwork.
On straight duct, the benefit of the FG model comes from its cast iron hopper, which makes the process automatic—the weld pins are poured into the hopper and fed automatically through the weld process. The MF style is a slower, manual process—the weld pins are placed on the ductwork and the gun is used to weld each one through the liner to the metal. If a shop has only one Pinspotter, it’s almost always the MF series because of it’s versatility: the ability to move the machine around the shop coupled with it’s 12 ft cable that reaches into fittings that would not be possible with a fixed head pinspotter.
But when it comes to jobs with a high percentage of straight duct, the process of Lining the duct is much slower.
In 2020 Duro Dyne introduced the FPP5 Bulk Feed Conversion Platform that enables an MF series to be two machines in one. Compact and corded for fittings, then very quickly hooked up for performance as Bulk Feed machine with all of the power and speed of an FG/Mach 3 series.
