A popular phos-copper brazing alloy. Offers superior ductility and is the preferred choice when joint clearance and brazing temperature control are less than ideal.

#15 is used for the brazing of copper and copper alloys, brass and bronze. It can also be used for brazing silver, tungsten and molybdenum. It is very effective for joining pipe and tubing and is widely used for electrical work. #15 should not be used for brazing ferrous metals or copper alloys containing more than 10% nickel because of phosphorous embrittlement due to reactions with iron or nickel. Of the copper phosphorus brazing alloys, Brazeit 15 has more ductility and better electrical conductivity than the lower silver content phos-coppers. It has good flow and wetting properties on copper, brass and bronze. Of the phos-copper filler metals, #15 has the most “sluggish” flow characteristics. This enables it to fill gaps better. The recommended joint clearances are between 0.001″ and 0.005″. Melting of #15 is virtually complete at 1300ºF (704ºC) even though the liquidus is not yet reached. Best results are obtained when brazing slightly above this temperature.


Melting Pt. 1190 ºF
645 ºC
Flow Pt. 1300 ºF
705 ºC
MBT1 1500
AWS A5.8 BCuP-5
QQ-B-650 BCuP-5
MIL-B-15395 Grade III
QQ-B-654 BCuP-5
Preform Options Brazing Discs 
Brazing Rings 
Brazing Shims 
Brazing Washers 
Custom Designs 
Resale Options Brazing Rods 
Brazing Wire 
Approx. Wire Length (BCuP/lb.) (BAg/Tr.oz) 1080 in; 0.062 diameter
4340 in; 0.031 diameter
475 in; 0.093 diameter

Physical Constants

Solidus 1190 ºF
643 ºC
Liquidus 1475 ºF
802 ºC
Brazing Range 1300 to 1500 ºF
704 to 816 ºC
Specific Gravity 8.44
Density 4.45 T.oz./cu.in.
0.305 lb./cu.in
Electrical Conductivity 9.9 % IACS
Electrical Resistivity 17.4 Micro ohm-cm
Color Light Copper


The phosphorus content of #15 acts as 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 flux used must be active within the required temperature range of #15 and active throughout the heating cycle. The flow point of #15 is 1300 ºF (704 ºC).

Best for large gap application, clearance of .002" to .006". Least fluid of BCuP family. Easy to use.

Available Forms

Standard Forms of #15 are brazing wire, brazing strip, and brazing preforms.

Safety Information

The operation and maintenance of brazing equipment or facility should conform to the provisions of American National Standard (ANSI) Z49.1, "Safety in Welding and Cutting." For more complete information, refer to the Material Safety Data Sheet for #15.


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-5
  • EN: CP 102
  • Lucas: Silver-Fos 15
  • UNS: C55284


  • Brazing Temperature Range High: 1575 F / 857 C
  • Brazing Temperature Range Low: 1525 F / 829 C
  • Liquidus: 1475 F / 802 C
  • Solidus: 1190 F / 643 C



  • Cu: 80%
  • Ag: 15%
  • P: 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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