In addition, we produce these cup head weld pins with capacitor discharge (CD) weldable bases and supply them with self-locking washers as matched components. Meanwhile, we comply with SMACNA HVAC Duct Construction Standards for mechanical fastening of duct liner. Therefore, HVAC contractors and sheet metal fabricators rely on them for permanently attaching fiberglass duct liner, rock wool, and acoustic insulation to the interior of sheet metal ducts.[reference:0]

Technical Specifications of Duct Liner Weld Pins

To begin with, we manufacture our cup head weld pins in a range of diameters and lengths. Specifically, the table below summarizes the standard product range.

Material & Welding Specifications for Cup Head Weld Pins

• To begin with, we use low carbon steel (C – 0.23% max, Mn – 0.90% max) as the standard base material for our duct liner weld pins. This meets the metallurgical requirements for reliable CD welding.[reference:1]
• Moreover, we apply a zinc coating as standard, with copper plating available on demand. Copper plating improves electrical conductivity for capacitor discharge welding.[reference:2]
• Additionally, we supply the matching self-locking washers in galvanized mild steel with a domed, multi-lanced hole design for positive locking on the pin.[reference:3]
• Furthermore, our cup head weld pins achieve a minimum tensile strength of 60,000 psi and a minimum yield strength of 50,000 psi, with a minimum elongation of 20% in 2 inches.
• For special orders, we supply stainless steel 18-8 and aluminum pins for corrosion-sensitive or lightweight applications.[reference:4]
• Finally, we offer OEM & ODM — we customize pin diameter, cup head dimensions, length, plating, washer size, and packaging according to your specifications.

How Duct Liner Weld Pins Work — CD Welding & Self-Locking Retention

In fact, the duct liner weld pin offers a fast, permanent mechanical fastening method for insulation inside HVAC ductwork. Furthermore, it is the industry-standard solution for securing duct liner against high airflow and vibration.[reference:5]

To begin with, you weld the pin to the sheet metal duct using a capacitor discharge (CD) stud welder. Meanwhile, the welding process creates a strong, permanent bond between the pin base and the galvanized steel duct surface.[reference:6]Then, you push the insulation over the protruding pin. After that, you press a self-locking washer (speed clip) onto the pin up against the insulation. Finally, you clip off or bend over the remaining pin portion for a permanent attachment.[reference:7]

Therefore, the combination of CD welding and self-locking washers ensures the insulation stays securely in place even in high-vibration or high-airflow environments. Moreover, most duct liner specifications require this mechanical fastening in addition to adhesive bonding, to fulfill SMACNA requirements.[reference:8]

Key Advantages of Duct Liner Weld Pins

• First, the cup head design provides a larger bearing surface and allows the pin to move smoothly through automated hoppers and feed systems.[reference:9]
• Second, the beveled washer edge prevents the washer from cutting into the insulation facing, preserving the insulation’s integrity.[reference:10]
• Third, the CD weld process directs heat to the point of contact, reducing smoke and possible liner damage compared to resistance welding.[reference:11]
• Finally, the self-locking washer presses onto the pin and provides positive locking without the need for special tools or secondary operations.

About Our Factory — Direct Manufacturer of Duct Liner Weld Pins

In fact, Tarco Industry operates a modern manufacturing facility. Specifically, we dedicate it to the production of duct liner weld pins and HVAC insulation fasteners.

Furthermore, we complete every step in our own factory. This includes wire drawing, cold heading, cup head forming, plating, and packaging. Consequently, we do not outsource production. We do not act as a middleman.

In addition, we equip our factory with advanced cold heading machines and automated plating lines. As a result, we produce high-strength duct liner weld pins with consistent cup head geometry and reliable weld performance.

Therefore, whether you need standard cup head pins or custom configurations, Tarco Industry can produce them directly for you.

Factory Direct Advantages

• First, we are a Manufacturer, Not a Trader. You buy directly from Tarco Industry production lines, eliminating middleman markups.
• Second, we handle In-House Production. We produce pins, cup heads, and washers all under one roof for full quality control.
• Third, we welcome OEM & ODM. We customize pin dimensions, cup head sizes, plating, and packaging.
• Fourth, we maintain Bulk Production Capacity. We ensure stable output for large HVAC and industrial insulation orders.
• Finally, we provide Factory Price. We offer competitive direct pricing for distributors, insulation contractors, and OEMs.

Why Choose Our Duct Liner Weld Pins?

• For example, our pins offer Reliable CD Weld Performance. The copper-plated or zinc-coated base ensures consistent electrical conductivity for capacitor discharge welding.
• In addition, they provide Cup Head Retention. The cupped head design holds insulation firmly and allows smooth movement through automated feed systems.
• Moreover, they feature Precision Cup Head Forming. Consistent cup head dimensions ensure reliable welding contact and insulation retention.
• Furthermore, they ensure Secure Insulation Retention. Self-locking washers with beveled edges hold insulation firmly without cutting the facing.
• As a result of their Corrosion Resistance, the zinc-plated or stainless steel pins resist rust in humid or outdoor environments.
• Finally, we provide Direct Factory Support. Tarco Industry provides technical guidance, samples, and custom production.

How to Install Duct Liner Weld Pins

1. First, prepare the duct surface. Clean the sheet metal surface to remove rust, scale, oil, and moisture for proper electrical contact.
2. Then, load the pin into the welder. Place the cup head weld pin into the CD stud welder chuck.
3. Next, weld the pin in place. Press the welder perpendicular to the duct surface and activate the weld. The CD process creates a strong, permanent bond.[reference:12]
4. After that, impale the insulation. Push the duct liner or insulation material over the protruding pin until it rests against the duct surface.
5. Finally, secure with self-locking washer. Press the self-locking washer onto the pin up against the insulation. Clip off or bend over the remaining pin portion for a permanent attachment.[reference:13]

Applications & Industries for Duct Liner Weld Pins

• For instance, in HVAC duct systems, contractors use our pins to attach fiberglass duct liner and external insulation to sheet metal ducts.[reference:14]
• Also, in acoustic duct lining, they secure sound-absorbing insulation to reduce noise transmission through ductwork.[reference:15]
• In addition, for air handling units (AHUs), they fasten insulation to internal surfaces of AHU panels and enclosures.[reference:16]
• Furthermore, in industrial ductwork, they hold thermal insulation in place to maintain temperature control and energy efficiency.[reference:17]
• Lastly, in marine and offshore ventilation, they secure insulation in duct systems on ships and platforms.

Quality Assurance & Certifications

Furthermore, Tarco Industry manufactures our duct liner weld pins under strict quality control. Specifically, they comply with SMACNA HVAC Duct Construction Standards for mechanical fastening, and industry standards for ASTM C1071 insulation and UL181 air duct materials.[reference:18]

As a result, we perform dimensional inspection, plating thickness verification, and weld testing. Moreover, we test every production batch before shipment.

• Additionally, we offer certifications including ISO 9001, CE, and SGS.
• Similarly, our production capacity reaches 500,000 pcs per month.
• Also, we set the MOQ at 10,000 pcs (negotiable for sample orders).
• In terms of packaging, we offer bulk cartons on pallets with custom marking.
• Finally, we deliver within 15–20 business days after order confirmation.