The Duro Dyne MFPT Compact Pinspotter was staple in duct shops throughout the USA for many decades.
For smaller shops, it was their sole means of spotting weld pins to ductwork; for larger shops it was used on all lined fittings and the FG-1 Bulk Feed pinspotter was used on Straight Duct. The fact that these little machines, the last one of which was manufactured over 15 years ago, are still used in many shops, is a testament to their quality.
Though the MFPT is no longer available, it continued in the next generation of compact pinspotters, first with the MF12, then the MF12A and now the MF70.
While the differences between the three latest renditions are minimal, there are significant differences between those three and the MFPT. The process is unchanged in that the weld pins are typically placed by hand thru the Fiberglass Duct Liner which covers the inside of the ductwork. Then the operator welds down each pin, thru the liner spotting to the metal.
In some instances like Double Wall Spiral Pipe, the operator places the weld pin on the magnetic tip plate of the gun and then welds down.
Placing weld pin on gun tip prior to welding the solid inner wall of double wall spiral duct
Differences between the MFPT and today’s version:
Capacity:
The MFPT had a capacity of welding pins to 24 gauge Galvanized; the MF12A and MF70 have larger, 10 KVA transformers and the capacity of spotting pins on up to 16 gauge thickness.
Weight:
The rectangular shaped MFPT had a weight of 75 lbs while the more box-like shaped MF12A and MF70 are 120 lbs.
Because this weight puts it on the cusp of portability, some shops spend an extra few hundred to add a welding cart like this one from Klutch, available at online sellers.
Gun Cable length:
For most shops, the value in a portable pinspotter has more to do with the cable extending from the machine to the weld gun. Unlike a Bulk Feed Automatic and Stationary Pinspotter with a fixed position, the cable allows the shop to reach in and fasten pins thru liner at angles not possible with a fixed head.
The MFPT had a 7 ft Gun Cable length; the MF70 comes with a 10 ft gun cable length and will weld with a 15 ft Cable as long as the ground is sufficient.
Gun Style :
The weld Gun on MF12A and MF70 is more ergonomic. The MFPT, MF12 and even early versions of the MF12A had a cable extending from the back of the gun. The most recent years of MF12A and all MF70 versions have guns with Cables coming out the bottom which means less wear and tear on the cable, more ergonomic feel for the operator and better ability to get into tighter spaces.
Amp Pull:
Though there are no changes on the 220 Volt 1 phase requirement, the MF70 does pull more amps. The MFPT pulled 30 amps, and at least a 60 amp breaker is required for the MF70.
Why invest in a Compact Pinspotter in the first place?
If a duct shop has been using Self Adhesive Hangers with Washers, the investment in a Compact Pinspotter speeds up the Lining process over 20% (but the real factor is the savings in cost of fasteners). The SAH style (Self Adhesive Hanger) and washers as well as the Banger style pins both cost considerably more than weld pins—anywhere from 25% to 50%.
Versatility of adding the Bulk Feed Platform at any time:
At any time in the future, the shop can add the FPP70 5 ft Bulk feed Platform and alternate between using use this as an Automatic Pinspotter for Straight Duct and a portable model for Fittings.
Sold separately from—but used specifically for the MF, the MF12A, and the MF70—this Bulk Feed Platform with a 5 ft throat, gives any shop the ability to turn their portable Pinspotter into an FG style Bulk Feed automatic model thereby increasing speed by 3x faster. A simple disengagement of the Weld Cable and a simple twist-in hose hook up to the Mechanics of the Conversion Platform makes for a fast conversion to an automatic feeding of pins from vibrator bowl.
