How to Make Flux for Solder

Flux is a substance that is used to help fuse together two or more metallic surfaces with solder. Every metal has a layer of oxide on it. Flux cleans the oxide off and allows the solder to bond directly with the "bare" metal. This creates a very strong fusion. Flux is used by jewelers, leaded-glass window makers, welders---anyone who needs to solder metal together---and it is simple and inexpensive to make yourself.

Difficulty: Easy

Instructions

Things You'll Need:

• Protective eyewear
• Thick rubber gloves
• 2-quart pot
• Distilled water
• Boric acid crystals
• Sodium phosphate
• Powdered borax
• 1-quart glass jar or plastic tub with a lid

1. Don your protective eyewear and rubber gloves.

2. Combine the following ingredients in order in a 2-quart pot: 1 quart (32 ounces) distilled water, 7 tbsp. boric acid crystals, 4 1/2 tbsp. sodium phosphate and 5 tbsp. powdered borax. Stir constantly as you add the dry ingredients.

3. Place the pot on the stove. Bring the mixture to a boil, stirring often.

4. Remove the mixture from the heat, turn off the stove and allow it to cool. As it cools, the mixture will harden.

5. Pour the mixture into the quart container while it is still in a semi-liquid state. Do not cover the container until the flux has cooled completely.

Tips & Warnings

• Wash your pot and implements thoroughly after use. Take care not to get any ingredients on your skin. If you do, flush with cold water.

References

• How to use flux and solder.