Cup Alloys - For Refrigeration Engineers -


UK Silver Price
28th Mar 2017


  For the Refrigeration Engineer

There are several alloys widely used in the refrigeration and air conditioning industries. Whether you are a manufacturer, installer or repairer of refrigeration plant , CuP Alloys, as a specialist supplier of brazing materials, has the right alloy, in the right form at competive prices. Every packet carries a Certificate of Conformity with tips to ensure the production of strong leak-free joints.

Further information on the successful and economical use of brazing alloys and silver solder can be found in the section "Best Brazing Practice".

Brazing Copper

There are several copper phosphorus alloys, for brazing copper to copper, without the need for a flux. They have a silver content ranging from 0 - 18% silver. There is an alloy to meet the service conditions of the joint, customers specification and the International Standard ISO 17672 CuP179. All are supplied ex-stock in clearly labeled packs of 0.5, 1 and 5kg.

They should not be used to braze copper or brass to ferrous or nickel alloys. A weak brittle inter-metallic compound is formed in the joint that leads to premature joint failure.

Silver Free Alloys

CuP6 and CuP7 are good, general purpose silver free alloys for brazing copper that will suit most applications. They produce high quality joints economically.  CuP6 contains 6% phosphorus conforming to ISO 17672 CuP 179 - melting range 705 - 810 deg C. It is a relatively slow running alloy suitable for bridging larger gaps and brazing overhead.

CuP7 contains more phosphorus, is more free flowing and offers greater joint penetration. Melting Range 705 - 800 deg C. It is a ready substitute for S2. Use either on low stressed joints operating down to -10 deg C.
Both are available ex-stock in rod form 500mm x 1.5 -3.0mm dia and the popular 500 x 2 x 2mm square rod.

Silver Bearing Alloys

These alloys contain between 0.4 and 15% silver. The advantages offered by the silver are

increased joint ductility at ever decreasing temperatures,

greater corrosion resistance,  

greater resistance to vibration and thermal shock,

lowering the brazing temperature and

improving alloy fluidity.

Ensuring total penetration of the alloy into joint, reduces the risk of "ice blisters". The most common cause of joint failure, lack of penetration, is eliminated. Set the joint design for brazing (NOT WELDING), heat it to promote flow. See "Best Brazing Practice" for more information

Ag2P - use it down to - 20 deg C
Ag5P/Ag6P - use down to - 30 deg C
Ag15P is the most durable and probably easiest alloy to use. It meets the most demanding operational conditions.
Ideal for temperatures down to -40 deg C. Often used on underfloor pipe runs.

Silver Solder

The most common alloys are 55%, 40% and 38% silver. All are cadmium free.
455 melts at 630 - 660 deg C with good fluidity and will produce strong joints with only a small fillet
440 melts at 650 - 710 deg C is intrinsically cheaper and offers better gap filling properties.
438 melts at 650 - 720 deg C behaves very similarly to 440 but with the obvious advantage of a price reduction.

All alloys are available as bare rod 500mm x 1.0-2.5mm dia.
They are also available as flux coated rods 500mm x 1.5-2.0mm dia








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