106 How to Repair a Pot Metal Carburetor at 350°F with Super Alloy 1
Pot metal is an alloy called by many slang terms: pot metal, monkey metal, and zinc die cast to name a few. Regardless of what you call it, this soft metal can sometimes be difficult to repair due to its low melting temperature and differing metallurgic composition. Typically comprised of a blend of copper, zinc, tin, aluminum, lead, cadmium or iron, pot metal is a soft metal with that melts around 787°F–making most solders useless for pot metal repairs. Super Alloy 1 is a multi-metal solder with a 350°F working temperature, making it an ideal solution for all your pot metal repair needs–including pot metal carburetor repair.
In this video, we utilize a propane torch and Super Alloy 1 alloy to repair a pot metal carburetor. After removing all the oxidation from the parent metal with a wire brush (this task can also be performed with a wire brush, sandblaster, Dremel tool etc, just be sure to completely clean off all oxidation just prior to welding to ensure a proper bond) we begin the carburetor repair. Remove all gas and flammable liquids before applying heat to the carburetor.
Due to the size of the carburetor, we pre-heated the part broadly and thoroughly with a propane torch prior to making the repair. Pre-heating the part is necessary to optimize the flow of the flux.
Dip the solder rod into the honey flux and apply it to the repair area. Continue to move the torch to avoid overheating the flux. Overheating the flux will turn it black. If this happens, simply remove the flux with warm water and a wire brush and begin again.
Notice the flux’s transformative action–as the part heats to the proper melting temperature, the flux changes from a honey color to root beer brown. When you see the flux turn root beer brown, this is a visual indication the pot metal has reached Super Alloy 1’s working temperature and it’s time to add the solder rod.
Allow the metal to air cool slightly before using a wire brush and warm water to remove the flux residue. To smooth the solder, use a Dremel tool and grind to a finish.