Brazing

[metalbender]

Hello to all Still fairly new here, time for an odd question. I have had good success with my Forney twin carbon arc torch, heating, bending ,brazing with the ole' buzz box. I know it's old tech but I don't have an oxy set. I now have a Dynasty 200 dx and did some brazing, works quite well even though a waste of argon. I would like to hear if others have done this also, could regular compressed air be used to cool the torch??? Some artsy type stuff just needs to be brazed and the control with the tig torch is the answer. The flux on the rod does it's thing, the air would cool the torch for free. Some input pos or neg would be appreciated. Some comments like " are you nuts" will also work. Thanks Fred

[kcstott]

Argon is not used to cool the torch as much as it is used to protect the tungsten from degrading and oxidizing. If this is working for you then just turn down the argon to only protect the tungsten.

[davedarragh]

Brazing with TIG

Hello to all Still fairly new here, time for an odd question. I have had good success with my Forney twin carbon arc torch, heating, bending ,brazing with the ole' buzz box. I know it's old tech but I don't have an oxy set. I now have a Dynasty 200 dx and did some brazing, works quite well even though a waste of argon. I would like to hear if others have done this also, could regular compressed air be used to cool the torch??? Some artsy type stuff just needs to be brazed and the control with the tig torch is the answer. The flux on the rod does it's thing, the air would cool the torch for free. Some input pos or neg would be appreciated. Some comments like " are you nuts" will also work. Thanks Fred

Actually the process is quite common. You need to use Silicon-Bronze Rods, with NO FLUX. Nickel-Bronze, Aluminum-Bronze, and Manganese-Bronze are used as well. DO NOT use a Phosporus-Bronze or Silicon-Phosporus rods, as they contain Zinc. Zinc burns out under the TIG arc and the Phosporus causes cracking in steels.

Use lower amps than normal, and lay your beads as if you were welding, with Argon as your shielding gas.

The primary purpose of shielding gas(es) is to protect the molten weld metal from contamination by the oxygen and nitrogen in the air. Gas-cooled (air-cooled) torches do use the argon to help cool the torch. It dissapates the heat as well as protects the weld pool. C-25 and CO2 cool MIG guns as well.

It is particularly critical the proper pre and post flow rates are used in GTAW, as preflow clears the line of moisture and contaminants, and postflow to prevent oxidation of the weld area and tungsten by expediting the COOLING process.

If you research duty cycles for TIG torches and MIG guns, you'll find major differences between gas-cooled (air) and water cooled torches, as well as MIG guns using 100% CO2 compared to C-25 and flux-cored (self-shielded) guns.


Dave