METRO SUPPLY COMPANY - "A Supplier of Mechanical and Acoustical Insulation Products"

NEW JERSEY:  (973)-237-1551 
NEW YORK:   (718)-383-0117
VIRGINIA:       (571)-667-6366

GripNail Fastening Systems Logo


Weld Pins


PowerPoint weld pins are used to fasten duct liner insulation to the inside of sheet metal air ducts. These fasteners are usually applied when the ductwork is being fabricated in sheet metal shops. The fasteners have been specifically designed to work with all currently available duct liners (usually fiberglass duct liner insulation) and standard resistance welding type application equipment.

Beveled Edge Cap

Prevents tearing of duct liner insulation

Faster Welds

Forged diamond point design creates more electrical resistance for faster welds.

Better Plating

Zinc and Chromate plating exceeds SMACNA standards and gives a more professional appearance.

Reduced Down Time

Consistent point quality reduces frequency of machine adjustments.

Stronger Welds

Hardened steel point assures positive electrical contact for complete sheet to pin fusion.

Applied with Standard Equipment

Easily applied with Gripnail's Automatic Pin Welder or most standard hand held or hopper fed resistance welders.

Manufactured with pride in the USA

To the highest possible quality control standards.



A Gripnail is a unique mechanical fastener used to attached duct liner insulation to sheet metal. It was specifically designed to fasten acoustical duct liner to the inside of heating, ventilating and air conditioning ductwork. This operation generally takes place when the ductwork is being manufactured.


Gripnails are driven through the insulation and into the sheet metal with controlled impact. The hardened tapered teeth of the fastener bite into the sheet metal without puncturing. A hardened steel back-up plate is required to properly set the teeth of the Gripnail in the sheet metal.

The impact of Gripnail when driven into sheet metal causes tapered teeth at it's tip to close, biting into and holding the softer metal but not puncturing it.

A permanent attachment is formed with the hardened steel fastener "nailed" to the sheet metal. A pre-attached cap holds the duct liner firmly in place.

Gripnail fasteners withstand pulls up to 120 lbs., far exceeding SMACNA application standards. Extensive tests also demonstrate Gripnail fasteners have superior corrosion resistance, surpassing SMACNA's 96 hours saltspray test.

Equipment and Machines


Gripnail machines were first introduced to the HVAC industry in 1970 and have proven their reliability in the most severe duct manufacturing environments.

Metro Supply Company distributes all the Gripnail Fastener machines and equipment for both Gripnailers and Power Pins.  The equiment varies from portable hand welders to multi-headed sheet metal shop welders.