A very fluid alloy suited for tight joints. Its low brazing temperature and narrow solidus-liquidus range makes it ideal for applications where temperature is a factor or in cases where extended heating rates are encountered – such as furnace brazing.

#18M is a ternary alloy of silver, phosphorus, and copper approaching the eutectic composition. It is very fluid at brazing temperature and should be used on well fitted joints. #18M’s low brazing temperature and narrow solidus-liquidus range makes it ideal for applications (where temperature is a factor and with slow heating rates) such as in furnace brazing.


Melting Pt. 1190 ºF
643 ºC
Flow Pt. 1230 ºF
666 ºC
MBT1 1270
AWS A5.8 BCuP-8
Preform Options BCuP-8
Resale Options Brazing Rods 
Brazing Wire 
Approx. Wire Length (BCuP/lb.) (BAg/Tr.oz) 1100 in; 0.062 diameter 
4390 in; 0.031 diameter 
487 in; 0.093 diameter

Physical Constants

Solidus 1190 ºF
643 ºC
Liquidus 1230 ºF
666 ºC
Brazing Range 1225 to 1350 ºF
663 to 732 ºC
Specific Gravity 8.35
Density 4.40 T.oz./cu.in.
0.302 lb./cu.in
Electrical Conductivity 6.0 % IACS
Electrical Resistivity 29.0 Micro ohm-cm
Color Light Copper


#18M is used for brazing copper and copper alloys, such as brass or bronze. It is suitable for use on silver, tungsten, and molybdenum. It should not be used on ferrous or nickel alloys. On copper to copper applications, it is self-fluxing due to the fluxing action of the phosphorus content. It’s low melting temperature makes it ideal for application on copper to brass where temperature and dezincification is a factor.

Automatic brazing of copper and copper products.

Available Forms

Standard forms of #18M are brazing wire and brazing preforms.

Safety Information

The operation and maintenance of brazing equipment or facility should conform to the provisions of American National Standard ANSI/ASC Z49.1, “Safety in Welding, Cutting, and Allied Processing”. For more complete information, refer to the Material Safety Data Sheet for #18M


Download SDS Sheet

Bellman-Melcor distinguishes itself as a provider of premium quality brazing alloys at industry competitive prices. Our extensive inventory of brazing and soldering alloys ensures that in most cases your order can be available for immediate delivery.

Compare With



  • Brazing Temperature Range High: 1330 F / 721 C
  • Brazing Temperature Range Low: 1280 F / 693 C
  • Liquidus: 1230 F / 666 C
  • Solidus: 1190 F / 643 C



  • Cu: 75.75%
  • Ag: 18%
  • P: 6.25%

The information and recommendations contained in this publication have been provided without charge & compiled from sources believed to be reliable and to represent the best information available on the subject at the time of issue. No warranty, guarantee, or representation is made by the Prince and Izant Company, Inc. as to the absolute correctness or sufficiency of any representation contained in this and other publications; Prince and Izant Company, Inc. assumes no responsibility in connection therewith; nor can it be assumed that all acceptable safety measures are contained in this and other publications, or that other or additional measures may not be required under particular or exceptional conditions or circumstances. The company and product names referenced herein are for identification purposes only. All trademarks and registered trademarks are the property of their respective owners.

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