16301121 - Tweco 63J3 Nozzle Insulator for Spray Master 350 MIG Guns

Keep Your Spray Master 350 Running Smoothly

If you are running a Tweco Spray Master 350 MIG gun, you know it's a workhorse in the shop. However, even the toughest guns need maintenance, and the nozzle insulator is one of the most important small parts to keep an eye on. The Tweco 63J3 (part number 1630-1121) is the direct replacement insulator for your 350-amp setup. Its primary job is to keep the electricity where it belongs—at the contact tip—and stop it from traveling to the nozzle. If your nozzle shorts out against the table or the part you are welding, a worn or missing insulator is often the culprit.

Over time, heat and spatter can crack or degrade the insulator inside your gun. When this happens, you might experience erratic arcs, poor gas coverage, or a nozzle that won't stay tight. Swapping in a fresh 63J3 insulator is a quick and inexpensive fix that restores the safety and performance of your torch. This genuine Tweco part is built to handle high heat without melting or deforming, ensuring that your nozzle stays electrically cold and easy to remove for cleaning.

Installation is straightforward: simply remove the nozzle and the old insulator, then slide the new 63J3 onto the conductor tube or diffuser assembly (depending on your specific gun configuration) until it seats firmly. It is designed to hold the nozzle securely in place while allowing for the necessary gas flow. Don't let a five-dollar part ruin a thousand-dollar weld or damage your machine.

Whether you are fabricating structural steel, repairing heavy equipment, or working in a production line, keeping a few spare 1630-1121 insulators in your toolbox ensures you are never stuck waiting for parts. Trust genuine Tweco components to keep your Spray Master gun performing like the day you bought it.