handy fluxhandy flux

How is Flux Used in Jewelry Making?

Jewelers use flux during soldering to prevent oxidation and help the solder flow. Learn about different types of flux and which products work best.

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Flux is a soldering compound that keeps the soldering joints clean by blocking oxygen, which causes oxidation. Flux cleans, coats, and protects the piece and enables the solder to flow easily between the joints when heated. We'll discuss these uses and share some product recommendations.

Coating Flux

After pickling the item, coat/dip it first in a boric acid flux that protects the entire piece from oxidation and fire scale (heavy oxidation that forms on the jewelry from copper in the metal). Fire scale is very difficult to remove.

60% boric acid and 40% denatured alcohol yields an excellent and inexpensive flux. Add the boric acid to the alcohol until it stops dissolving and forms a thin paste. Dip the entire item into the solution, then dry it with gentle heat from your torch. Do this three or four times before soldering.

You can find boric acid and denatured alcohol at your grocery store or online.

Flow Flux

Now, you need a flux at the solder joint to help melt the solder without oxidation. This is called flow flux. Batterns and Handy Flux are the top choices. You can also use boric acid and water.

  • Batterns Self-Pickling Flux is used for hard soldering (solder that melts at a high temperature) of gold, silver, and platinum. It can be diluted with distilled water if it's too thick. Don't be fooled by the name. You'll still need to pickle the item before soldering. You can buy this from Amazon in 1, 3, 8, 16, and 128 oz jars.
batterns flux
Batterns Flux
  • Handy Flux is used for easy and medium soldering (solder that melts at a lower temperature) of gold and silver. It can also be diluted with distilled water if it's too thick. You can buy this from Amazon in 7 oz, 1/2 lb, and 1 lb jars.
handy flux
Handy Flux
  • Borax and water has been used by jewelers for years. While cheap, it also leaves a glassy, tough-to-remove coating on jewelry. You can purchase borax in the detergent aisle at your grocery store.

Use enough flux to protect the joints from oxidation, but not so much that it prevents the solder from flowing. Flux will bubble when the torch first touches it, and too much flux will create a lot of bubbles. The bubbling may cause your solder piece to shift, so preheat the flux a bit and then add the solder piece.

Flux dries out easily. Keep enough in a small vial to complete the job. Store the rest in an airtight container.

Jewelry Pickle Pot Kit Recommendations

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Megan Coward, Graduate Jeweler Gemologist, GIA, Graduate Gemologist

Megan Coward is a graduate of the GIA with Graduate Jeweler Gemologist and Graduate Gemologist accreditations. She has 20+ years in the retail jewelry industry in various roles including as a diamond buyer and gemstone appraiser.

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