Brazing Filler Metal Composition and Temperature Chart

Brazing filler metals are selected for the base metals, joint design, clearance, service conditions, and qualified process. This reference compares five named products from one manufacturer so their published nominal compositions and melting ranges can be read side by side.

Selected filler metal data

MECHANITEC / ENGINEERING REFERENCE

Selected aluminum, copper, and silver brazing filler metals

Selected Lucas-Milhaupt product data for aluminum, copper, and silver-bearing brazing filler metals.

1–5 of 5 matching rows (5 total)

Selected aluminum, copper, and silver brazing filler metals — page 1 of 1
Filler metal	Family	Nominal composition (wt.%)	Solidus (°C)	Liquidus (°C)	Manufacturer note
AL 718	Aluminum-silicon	88 Al / 12 Si	577	582	Manufacturer describes it as a eutectic aluminum-silicon alloy for aluminum base materials.
CDA 102	Copper	99.95 Cu	1083	1083	Pure-copper filler; manufacturer notes very fluid flow and a need for tight clearances.
SIL-FOS 6	Silver-copper-phosphorus	6 Ag / 86.75 Cu / 7.25 P	643	691	Manufacturer describes a very fluid alloy for close-fit work.
SILVALOY 202	Silver-copper-zinc	20 Ag / 45 Cu / 35 Zn	713	816	Manufacturer lists use with ferrous and non-ferrous metals and heat-treating operations.
SILVALOY 300	Silver-copper-zinc	30 Ag / 38 Cu / 32 Zn	677	766	Manufacturer describes it as a general-purpose intermediate-temperature filler.

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How to read solidus and liquidus

The solidus is the temperature at which melting begins; the liquidus is the temperature at which the filler is fully liquid. Between those values, solid and liquid phases coexist. A narrow interval can make a filler behave differently during heating than an alloy with a broader melting range. These temperatures describe the filler metal and are not a recommended torch setting or a universal brazing temperature.

The table includes AL 718, a nominal aluminum-silicon filler; CDA 102 copper; SIL-FOS 6, a copper-phosphorus alloy with silver; and two silver-copper-zinc products. The product pages list different flow and application characteristics, so composition alone is not enough to choose a filler. For example, the manufacturer notes that CDA 102 is very fluid and calls for close clearances. The phosphorus-bearing SIL-FOS 6 is also described as very fluid for close-fit work.

Selection checks before using a filler

First confirm that the filler is compatible with both base metals and the required service environment. Review the product technical data sheet for the exact form, flux requirements, recommended clearance, heating method, and joining limitations. Consider corrosion, operating temperature, joint loading, dissimilar-metal effects, and any applicable industry code. A product’s nominal chemistry does not establish the certified chemistry of a particular batch.

Next verify that the joint can be assembled with the specified fit and cleaned using the process required by the manufacturer. Oxides, contamination, excessive clearance, and uneven heating can prevent capillary flow even when the filler itself is suitable. Use a qualified procedure and representative test joints when performance matters.

Limits of this comparison

These are selected manufacturer product examples, not an exhaustive alloy catalogue. The values are transcribed from the linked product pages and should be checked against the current technical data sheet before procurement or production. This table does not provide joint strength, design allowables, procedure qualification, or interchangeability approval. Do not infer a safe process temperature by adding an arbitrary margin to solidus or liquidus.

Sources

Product compositions, melting ranges, and application notes come from the manufacturer’s pages for AL 718, CDA 102, SIL-FOS 6, SILVALOY 202, and SILVALOY 300. Check the latest product data and qualified joining procedure for the application.