This phos-copper brazing alloy delivers moderate liquidity and improved gap filling compared to Brazeit #0. The 5% silver content provides good economy when compared with #5.

#5 is used for the brazing of copper and copper alloys, brass, and bronze. It can also be used on silver, tungsten, and molybdenum. It is primarily used for the joining of copper-to-copper. Brazeit 5 should not be used when brazing ferrous metals or copper alloys containing more than 10% nickel because of phosphorus embrittlement due to reaction with iron or nickel. #5 has good flow and wetting properties on copper, brass, and bronze. Its melting characteristics are such that on the low end of its brazing temperature range it has “sluggish” flow characteristics which enable it to fill gaps better, making it ideal for loose-fitting joints. On the other hand, when brazing at the high end of its brazing temperature range, it is very fluid, making ideal for tight-fitting joints requiring deep penetration.


Melting Pt. 1190 ºF
643 ºC
Flow Pt. 1495 ºF
813 ºC
MBT1 1500
AWS A5.8 BCuP-3
QQ-B-650 BCuP-3
Preform Options Brazing Discs 
Brazing Rings 
Brazing Shims 
Brazing Washers 
Custom Designs 
Resale Options Brazing Rods 
Brazing Strip 
Brazing Wire 
Approx. Wire Length (BCuP/lb.) (BAg/Tr.oz) 1120 in @ 0.062 diameter 
4500 in @ 0.031 diameter 
490 in @ 0.093 diameter

Physical Constants

Solidus 1190 ºF
643 ºC
Liquidus 1495 ºF
813 ºC
Brazing Range 1325 to 1500 ºF
718 to 816 ºC
Specific Gravity 8.13
Density 4.29 T.oz./cu.in.
0.294 lb./cu.in
Electrical Conductivity 9.6 % IACS
Electrical Resistivity 18.1 Micro ohm-cm
Color Light Copper


The phosphorus content of #5 acts as a fluxing agent and no flux is necessary when brazing copper-to-copper joints. However, when used with a copper alloy or one of the other brazeable metals, a brazing flux must be used to promote wetting, bonding, and flow throughout the joint. The flow point of #5 is 1325 ºF (718 ºC).

Used when gap clearance range is .003 to .006". Ideal for larger copper pipe sizes.

Available Forms

Standard forms of #5 are brazing wire and brazing preforms.

Safety Information

The operation and maintenance of brazing equipment or facility should conform to the provision of American National Standard (ANSI) Z49.1, "Safety in Welding and Cutting." For more complete information, refer to the Material Safety Data Sheet for #5.


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

  • AWS: BCuP-3
  • EN: CP 104
  • Lucas: Sil-Fos 5
  • UNS: C55281


  • Brazing Temperature Range High: 1595 F / 868 C
  • Brazing Temperature Range Low: 1545 F / 841 C
  • Liquidus: 1495 F / 813 C
  • Solidus: 1190 F / 643 C



  • Cu: 89%
  • P: 6%
  • Ag: 5%

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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