A Tale of 3 Guns: Spray Gun Selection for HVAC Adhesives and Sealants

Applying adhesives and sealants with the correct spray gun ensures clean coverage, proper spray patterns, and safe operation. Each product category uses a specific delivery system, so gun interchangeability is not possible. This guide offers a quick overview of the three spray systems used in HVAC applications.

Aerosol Adhesive Spray Guns

Aerosol materials rely on pressurized cylinders to move the product through the gun. As example, Hardcast’s Adjustable Spray Gun (SKU 307490) spreads the stream of adhesive in a “fan” pattern using a specialized tip (SKU 304301) via a hose connected directly to the adhesive cylinder (such as Low-VOC Travel-Tack, available in #40, #187 #375 sizes). This simple, all-in-one system is easy to transport and requires no external air or pump.

Application Advantages:

• Ideal for quick, mobile adhesive work
• Best with a fully Adjustable Spray Gun, rated up to 250 PSI
• Fan pattern created by a simple spray tip

Pail and Drum Adhesive Spray Guns

Water and solvent-based adhesives supplied in pails or drums use a diaphragm pump powered by shop air. These guns require two hoses. One delivers adhesive to the tip and the second atomizes (or splatters) the adhesive to create a uniform spray pattern.

Application Advantages:

• Best for controlled, higher volume adhesive applications
• Best with guns like the Binks 2100, typically rated up to 100 PSI
• Requires both fluid and air lines

Spray Applied Duct Sealant Guns

Duct sealants are applied with a piston pump that delivers material at very high pressure (up to 3,300). The pressure forms the fan pattern without the need for atomizing air. As example, our Mobile Delivery Sealant Delivery System uses a Graco Silver Plus Spray Gun which handles up to 5,000 PSI, exceeding the max pressure.  

Application Advantages:

• Ideal for large duct sealing projects
• Graco Silver Plus gun with Hardcast Mobile Sealant Delivery System
• Handles heavy-bodied sealants with consistent output
• Rated up to 5,000 PSI

Why Proper Gun Selection Matters

Each gun is engineered for a specific pressure range and hose configuration. Using the wrong gun can produce poor spray patterns, wasted material, or equipment failure.

• An aerosol gun cannot withstand the pressure of a piston pump.
• A high-pressure sealant gun will not produce a proper pattern on a low-pressure aerosol cylinder.
• Pail and drum adhesive guns require both a fluid and atomizing air line and cannot be replaced by single-line systems.

Matching the correct spray gun to the material, pump type, and pressure requirement ensures safer operation and consistent coverage on every job.