United Precious Metal Refining – 6 Steps to continued Success


United Precious Metal Refining, Inc. is a global supplier of master alloys, de-oxidized sterling silver, solder and wire products for the manufacturing of Gold, Silver, Platinum & Palladium jewelry. United PMR is also a primary refiner specializing in processing all types of materials from scrap to bench grindings and sweeps.

United PMR, Inc.’s understanding of the Gold & Silver soldering process is unparalleled in the jewelry industry. Here are a few tips to use during the soldering process to help aid in your continued success.

1. FITTING – Great care should be taken in the fitting of pieces to be joined. Make sure the surfaces are smooth, even, free of burrs and fit tightly. This will assure a strong neat joint requiring less finishing. Remember, “SOLDER WILL NOT FILL GAPS “.

2. CLEANING – All parts being soldered must be thoroughly cleaned. The joint areas and solder must be clean, free of oxidation, oil, grease, polishing compound and tape adhesive. If the area around the joint has a high luster, roughen the surface with a scotch brite pad.

3. PROPER SUPPORT – Clamps or jigs should be used to align and hold the objects being soldered. This will help prevent movement or shifting of the pieces during the soldering process.

4. FLUXING – The entire object should be given a fire coat of boric acid and alcohol with a brush. The object is then gently heated to form a protective coating to resist oxidation. The joint areas should be well coated with solder flux to allow for burn off during the soldering process. The Battern’s type liquid flux will only provide a thin coating and more flux may need to be applied to protect the solder joint. Paste fluxes can give better protection on some jobs as they provide a thicker coating.

5. HEATING – Use a slightly reducing flame (softer flame). Let the heat of the objects being joined flow the solder. Don’t try to force the solder to flow with the torch flame as this usually results in pitting or a poor quality joint. Use a steady even heat to the surrounding metal to a dull red color, and then concentrate the heat on the solder joint area. Do not overheat. It is best to keep the torch moving to provide an even heat. It is best not to use micro torches for ring sizing as the small intense flame usually overheats or oxidizes the joint. Remember, “SOLDER FLOWS TOWARD HEAT”.

6. CLEANING & PICKLING – Flux residue can be removed in hot water, a brush can be used to speed removal. Oxidation on the soldered objects can be removed in the pickle solution. Hot “Sparex” safety pickle is the most commonly used pickle solution and effectively removes any surface oxides. A 10 to 20% Sulfuric acid solution or a 30% Food Grade Phosphoric acid solution can also be used although “Sparex” is a much safer pickle.

With over 30 years of industry experience, it’s no wonder their customers refer to them as “Simply the Best.”