page4
Composition by weight %
Family
Solidus/liquidus
point (°C)
Toxic
Comments
Cu
Zn
Ag
Au
Pd
Pt
Ti
Cr
Mo
W
Mn
Fe
Co
Ni
Cd
Sn
Al
B
Si
P
other
Cu
75.9
Ag
17.6
P
6.5
Cu–
Ag–P
643
[15]
–
Sil-Fos 18. Eutectic. For copper, brass and bronze alloys. Self-fluxing on copper.
Extremely fluid. Good fitup required. Gap 0.025–0.075 mm. Gray color.
75.9
17.6
6.5
Cu
89
Ag
5
P
6
Cu–
Ag–P
643/813
[10]
645/825
[11]
645/815
[12]
–
BCuP-3, CP 104, CP4, Sil-Fos 5, Silvaloy 5, Matti-phos 5, SILVERPHOS 5.
Slow-flowing, very fluid. Less expensive than BCuP-5. Can fill gaps and form fillets.
Strong tendency to liquate. For copper tube brazing, used in plumbing. Used for
fluxless brazing in refrigeration, air conditioning, medical gas pipework, and heat
exchangers. Gap 0.051–0.127 mm. Flow point 720 °C. Light copper color.
Maximum service temperature 149 °C (intermittently 204 °C).
89
5
6
Cu
88
Ag
6
P
6
Cu–
Ag–P
643/807
[16]
–
Silvaloy 6. Flow point 720 °C. For copper, copper alloys, brass, bronze. Primarily
for copper-to-copper. Can be used also on silver, tungsten and molybdenum. Low
vibration resistance. Light copper color. Maximum service temperature 149 °C
(intermittently 204 °C).
88
6
6
Cu
86.75
Ag
6
P
7.25
Cu–
Ag–P
645/720
[12]
645/750
[17]
641/718
[18]
–
BCuP-4, Sil-Fos 6, Matti-phos 6, SILVERPHOS 6HP. Very fluid, fast flow, for
narrow joints. Low melting range. Flow point 690 °C. Lowest melting point from the
low-silver alloys. Low cost. Used for fluxless brazing in refrigeration, air
conditioning, medical gas pipework, and heat exchangers. Tends to liquate.
Extremely fluid above flow point, readily penetrates narrow gaps. Gap 0.025–
0.076 mm (0.05–0.2 mm). Less ductile than BCuP-1 or BCuP-5.
86.75
6
7.25
Cu
90.5
Ag
2
P
7
Cu–
Ag–P
705/800
[11]
–
CP 202, CP3. Gap-filling. Used in plumbing.
90.5
2
7
Cu
91
Ag
2
P
7
Cu–
Ag–P
643/802
[10]
645/875
[12][19]
643/788
[20]
641/780
[21]
–
BCuP-6, CP 105, Sil-Fos 2, Silvaloy 2, Matti-phos 2, SILVERPHOS 2. Medium
flow. Flow point 704–720 °C. Very fluid, can penetrate narrow gaps. Gaps 0.025–
0.127 mm (0.05–0.2 mm). Comparable to Fos-Flo 7. For copper, copper alloys,
brass, bronze. Primarily for copper-to-copper. Can be used also on silver, tungsten
and molybdenum. Low vibration resistance. Tends to liquate. Light copper color.
Maximum service temperature 149 °C (intermittently 204 °C).
91
2
7
Cu
91.5
Ag
2
P
6.5
Cu–
Ag–P
643/796
[22]
–
Silvaloy 2M. Medium flow. Flow point 718 °C. Very fluid, can penetrate narrow
gaps. For copper, copper alloys, brass, bronze. Primarily for copper-to-copper. Can
be used also on silver, tungsten and molybdenum. Low vibration resistance. Light
copper color. Maximum service temperature 149 °C (intermittently 204 °C).
91.5
2
6.5
Cu
91.7
Ag
1.5
P
6.8
Cu–
Ag–P
643/799
[23]
–
Silvalite. For copper, brass and bronze. Self-fluxing on copper. Also usable on
silver, tungsten, and molybdenum. Primarily for copper-to-copper joining. Low
resistance to vibrations. Good for tight-fitting copper pipes and tubing. Extremely
fluid, will penetrate even thin joints. Light copper color. Maximum service
temperature 149 °C (intermittently 204 °C). Flow point 732 °C. Optimal brazing
temperature slightly above flow point. Sluggish at low temperatures, suitable for
gap-filling. Very fluid at high temperatures, suitable for deep penetration to tight-
fitting joints.
91.7
1.5
6.8
Cu
92.85
Ag
1
P
6
Sn
0.15
Cu–
Ag–P
643/821
[24]
–
Silvabraze 33830. For copper, brass and bronze. Self-fluxing on copper. Also
usable on silver, tungsten, and molybdenum. Primarily for copper-to-copper joining.
Low resistance to vibrations. Good for tight-fitting copper pipes and tubing.
Extremely fluid, will penetrate even thin joints. Light copper color. Maximum service
temperature 149 °C (intermittently 204 °C).
92.85
1
0.15
6
Cu
93.5
P
6.5
Cu–P
645/740
[11]
–
CP 105, CP2. Gap-filling. Used in plumbing.
93.5
6.5
Cu
92.8
P
7.2
Cu–P
710/793
[10][25]
710/795
[12]
–
BCuP-2, Fos-Flo 7, Silvaloy 0, Copper-flo, PHOSCOPPER 0. Fast flow, very
fluid. Can withstand moderate vibration, not very ductile. For copper, brass and
bronze. Primarily for copper-to-copper. Can be used also on silver, tungsten and
molybdenum. For joining tight fittings and tubing, will penetrate narrow gaps.
Unsuitable for larger gaps, should be used only where good fitup can be
maintained. For heat exchanger return bends, hot water cylinders, refrigeration
pipes. Flow point 730 °C. Gap 0.051–0.127 mm (0.075–0.2 mm, 0.025–0.076).
Tends to liquate. Maximum service temperature 149 °C, intermittently 204 °C. Steel
gray color.
92.8
7.2
Cu
93.85
P
6.15
Cu–P
710/854
[12]
–
Fos-Flo 6. Ductile, moderate flow. Economical. Wide melting range. Use where
joint tolerances are larger and ductility is important. Flow point 746 °C. Gap 0.076–
0.127 mm.
93.85
6.15
Cu
97
Ni
3
B
0.02–0.05
Cu
1085/1100
[1]
–
CU 105. Fluid. Capable of bridging larger gaps than pure copper (up to 0.7 mm in
extreme cases).
97
3
0.05
Cu
99
Ag
1
Cu
1070/1080
[1]
–
CU 106. Slightly lower melting point than pure copper. More expensive due to silver
content. Rarely used now. Can be used after CU 105 in step brazing.
99
1
Cu
95
Sn
4.7
P
0.3
Cu–Sn
953/1048
[26]
–
CDA 510. Bronze. For steels where lower temperature than with pure copper is
required.
95
4.7
0.3
Cu
93.5
Sn
6.3
P
0.2
Cu–Sn
910/1040
[1]
–
CU 201. Bronze. Requires fast heating to avoid problems with wide melting range.
93.5
6.3
0.2
Cu
92
Sn
7.7
P
0.3
Cu–Sn
881/1026
[26]
–
CDA 521. Bronze. For steels where lower temperature than with pure copper is
required.
92
7.7
0.3
Cu
87.8
Sn
12
P
0.2
Cu–Sn
825/990
[1]
–
CU 202. Bronze. Requires fast heating to avoid problems with wide melting range.
87.8
12
0.2
Cu
86.5
Sn
7
P
6.5
Cu–Sn
649/700
[27]
–
Silvacap 35490. Bronze. Self-fluxing on copper. Generally provides joints stronger
than the base metals. Used for joining copper assemblies with low tolerances.
Maximum service temperature 204 °C, intermittently 316 °C.
86.5
7
6.5
Cu
86.8
Sn
7
P
6.2
Cu–Sn
657/688
[28]
–
Fos-Flo 670. Low-cost. Useful for joining copper to copper or copper alloys where
strong impacts and vibrations are not encountered. Requires good fitup. Self-
fluxing on copper. Silver-free. Extremely fluid above flow point, for tight-fitting joints.
Gap 0.025–0.075 mm. Light brown color.
86.8
7
6.2