How to Make Silver Solder Flux

Knoji reviews products and up-and-coming brands we think you'll love. In certain cases, we may receive a commission from brands mentioned in our guides. Learn more.
A brief How-To about making your own flux for soldering.

Flux is an agent used to bond two or more metals when they have been melted and soldered. Flux helps to clean impurities and oxidation from the surfaces of those metals so that the solder can bond with the pure metal, creating a strong connection. It also helps solder to flow more easily. Otherwise, it would form beads, or lumps. Metal workers, jewelers, and crafters use flux frequently and it is possible to make your own flux at home with only a few key ingredients. Here is a step by step guide on how to make your own flux from the comfort of your kitchen.

Using solder is used by everyone that is in electronics, from soldering to a circuit, to the home hobbyists and amateur radio operators. The need to make a good electrical connection between two copper pieces of wire is important. Without a good connection, there can be a bad connection that causes what you are building to not work.

It is also important to use a good soldering iron or soldering gun to make sure the heat is proper to not only heat the metal like copper, but also helps the solder flow smoothly, otherwise, you can get what is known as a cold solder joint, never good as a cold solder joint can just break off and not make the proper connection.




Table Salt



Mixing bowl or container with lid

Measuring cup



1. First, you will use the spoon and measuring cup to add 1 cup of borax to the mixing container. Borax can be found at most hardware stores and some grocery stores in the isle that has the laundry soaps and powders. (Borax is a powder used in most laundry detergent, so look near the detergent.)

2. Next, you will need to add 1/2 cup of table salt and mix the two dry ingredients together until blended.

3. Depending upon what type of flux you are trying to make, you can either use this dry flux formula, or you can also mix water to make it into a paste. Dry flux works just fine, but if you decide to add water you can add just enough to your mixture to make it into a pasty form. (Start off with little amounts of water and add more until you get your desired consistency.)

4. Use the flux as needed after you've made it successfully and to your liking. Place the lid on the container and keep it there until you are ready to use it again.

5. Be sure to seal up the containers of the ingredients you have used and to clean up any product you may have spilled while mixing. Wash your hands as well.


-Liquid flux is a bit easier to work with, while dry flux is commonly used to sprinkle on harder to reach areas.

-Potash can be used as an ingredient as well. Use the same amount of potash as borax and follow the recipe the same way from there.


Posted on Feb 27, 2013
Chuck Pick
Posted on Dec 16, 2012
Chuck Pick
Posted on Dec 16, 2012
Chuck Pick
Posted on Dec 16, 2012