Fos Flo® alloys are Copper based filler metals that are self-fluxing on copper by virtue of their phosphorous content. Because of their self-fluxing nature, you save time and money by eliminating the steps necessary to flux a joint before brazing. However, copper alloys such as brass and bronze should be fluxed with Handy Flux or Sure Flo Brazing Flux to assure a sound braze joint.

The level of phosphorous also changes the fluidity and ductility of the material. The greater the percentage of phosphorous in the filler metal the more fluid the material will be. While this alloy is widely used in the air conditioning and plumbing industries, it is not for use on ferrous or nickel based materials because the joint will become brittle and may fail.

Fos Flo® alloys have many of the same characteristics of the Sil-Fos materials, except that they are free from silver, which significantly reduces the price of the material. Alloy forms available include wire, preforms and powder.

Use the chart below to compare our most popular copper/phosphorus alloys.