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For vertical joints, any excess flux that runs down the tubing should be wiped clean, before
applying solder, as this will prevent solder from “chasing” the flux and eliminate wasted runs of
solder on the tubing.
6. Remove excess solder with small brush or rag while wet, leaving a fillet around end of valve as
it cools.
7. Allow a solder joint to cool to room temperature – Never shock a solder joint cool with water.
This could damage the integrity of the filler material.
BRAZING
1. Cut tube end square. Ream, deburr, and check for dry fit. Do not use tubing that is out of round
or fits so tightly into the solder cup that it must be forced or hammered into place.
2. Prior to preparing a solder cup for brazing on a valve:
Close a gate or globe valve fully, to avoid getting sanding fines in the seat well or damaging
the sealing surfaces
Remove the hanger assembly on a swing check valve.
Disassemble a three-piece ball valve and prepare the end connections.
WARNING: NEVER attempt to braze a two-piece ball valve or check valve.
Use sand cloth or a steel wire brush to clean both ends to a bright metal finish. Steel wool is not
recommended.
Apply flux immediately upon cleaning surfaces of joints to be brazed. If fluxed parts are allowed
to stand, the water in the flux will evaporate, and dried flux is liable to flake off, exposing metal
surfaces to oxidation.
3. Apply flux to outside of tube and inside of solder cup. Surfaces to be joined must be completely
covered.
4. Assemble joint by inserting tube into socket hard against the stop. The assembly should be
firmly supported so that it will remain in alignment during the brazing operation.
Prior to brazing:
Open fully a gate or globe valve, to prevent soldering the closure member to the seats.
Remove the hanger assembly on a check valve.
5. The best recommended fuel source is an oxy-acetylene flame.
NOTE: On one-inch and larger valves, it is difficult to bring the whole joint up to temperature at
one time. It will frequently be found desirable to use a double-tip torch to maintain the proper
temperature over the larger area. A mild pre-heating of the whole socket area is recommended.
Sweep flame around tube in short strokes up and down at right angles to run of tube. To avoid
burning through tube, the flame should be in continuous motion and not allowed to dwell on any
one point. Never direct the flame into the capillary gap between the tube and solder cup – always
work the flame away from the gap. Apply flame to valve at base of socket. Heat uniformly,
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