3 All-State®
No. 21 Phosphor—Copper
Alloy Torch Application
General Characteristics
A brazing rod containing the proper
balance of phosphorus to act as an efficient fluxing agent on all copper
joints. Offers: 1) Fast capillary action
on tight joints; 2) High electrical and heat conductivity; 3) High fatigue
resistance and tensile strength.
Typical Applications
Joining copper to copper without flux
or copper to copper alloys (brass and bronze). When joining brass and
bronze, All-State®
No. 21 Flux should be used. This alloy is widely used in the refrigeration, electrical
and plumbing industries
to join copper tubing and pipe, electrical wires and flexible tubing. No. 21 will
join copper-nickel alloys with
less than 30% nickel; not recommended for ferrous metals.
Qualities Tensile
strength —up
to 40,000 psi (28.13 kgs/mm2) Elongation
in 2" —19%
Working temperature —1445°-1460°F
(785°-793°C) Procedures
Clean parts to be joined. If light
sections of brass or bronze are being joined, All-State®
S-200 Paste Flux should be
used. When joining heavy sections of brass or bronze, All-State®
No. 21 Flux will give longer protection at higher
temperatures; no flux needed when joining copper to copper. All joints should
be tight fitting, clearance not to
exceed .003". The use of a large tip will give a broader heat and reduce application
time. When flux turns clear
or a dull red heat is reached, a small amount of No. 21 should be melted off;
continue heating until bonding
is complete. Operation should be fast; avoid overheating, and do not remelt. To
remove flux, submerge in
hot water and brush. To restore the copper color, immerse in 10 percent sulfuric
acid and water solution. Rinse
in hot water.
