#41
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TIG brazing aluminum machined stock to sheet
I think a good example of the 40F difference between the melting points of parent metal and a braze filler is this one:
P1080536 tig braze_aluminum.jpg You are looking at a German-made aluminum heat exchanger, air/oil. This design has been around for a long time, but the fittings and bracketry change per application (Mercedes 300). Problem: orig. exch. too old and decrepit and new ones are NLA. New one has the identical body but all machined fittings and bracketry are different. Solution: Whack off all needed pcs from orig and all non-essentials from new body, and Trading Places happens via tig boy and alu braze. Note: left side of machined alu fitting is next to factory furnace brazed joint, and my tig-braze fillet runs right up against the factory brazed fillet, but not melting it. Temps have to be delicately held to do this. (insert perspiration here) (had zero leaks and part fit exactly, with no warpage.) (ps, I first started doing tig-boy brazing in 1974, restoring a full set of 5 Very Rust Pitted wire wheels for a noted 12-string guitarist .... back to show-quality chrome, with zero defects. ... but I wuz young and got lucky and had zero pits in da krome .... )
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Kent http://www.tinmantech.com "All it takes is a little practical experience to blow the he!! out of a perfectly good theory." --- Lloyd Rosenquist, charter member AWS, 1919. |
#42
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Kent,
What is you comment about using silicon bronze to reinforce the outside of mild steel exhaust header tubes at the flange ? ( TIG welded on the inside of the flange ). Have you found cracking an issue ? Is brazing rod a better option ? Thanks Dave
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David Boles |
#43
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I've seen the tig bronze laid on those joints many times, as it saves the headers from separating there a little bit longer. If the headers have many miles on them be careful of the thin spots.
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Kent http://www.tinmantech.com "All it takes is a little practical experience to blow the he!! out of a perfectly good theory." --- Lloyd Rosenquist, charter member AWS, 1919. |
#44
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Some nice welding info on this from a supplier.
Silicon Bronze welder setup parameters for TIG and MIG ♦ RECOMMENDED WELDING PARAMETERS: *GMAW (MIG) Parameters (DC Reverse Polarity) Electrode Positive Spray transfer Wire Diameter Amps Volts Argon (cfh) Wire Feed (ipm) 0.030 130-150 21-23 25 460-500 0.035 145-185 23-25 30 400-440 0.045 195-215 26-28 30 280-310 1/16 260-280 27-30 40 150-210 *GTAW (TIG) Parameters (DCSP) ² Electrode negative or ACHF Material 2% Thoriated ² Filler Wire Size Amps (DC) Amps (AC) Gas Cup Argon (cfh) 1/16” 1/16” 1/16” 70-150 70-150 3/8-1/2 15 3/32”-1/8” 3/32” 3/32” 150-200 140-230 7/16-1/2 15 3/16”-1/2” 1/8” 3/32”-1/8” 230-400 225-320 7/16-1/2 20 1/2”-1“ 3/16” 3/16”-1/4” 325-500 290-485 1/2 25
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Kirk Last edited by KAD; 01-27-2016 at 06:35 PM. |
#45
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Quote:
not MIG or TIG welding?
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Kent http://www.tinmantech.com "All it takes is a little practical experience to blow the he!! out of a perfectly good theory." --- Lloyd Rosenquist, charter member AWS, 1919. |
#46
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Quote:
I thought it was interesting that they listed both DC electrode negative and ACHF (High Freq) setups for TIG. Sorry I thought that it was pertinent information to this discussion (I added a line stating that it was for silicon bronze)
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Kirk Last edited by KAD; 01-27-2016 at 06:36 PM. |
#47
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After reading on another forum about it, I tried tigging sil bronze on AC, very low cleaning setting, it flows out real nicely on AC.
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Mark from Illinois |
#48
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Quote:
So then, I guess DC is the automatic default setting ... ? AH, well ... Sometimes the obvious solution .... isn't.
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Kent http://www.tinmantech.com "All it takes is a little practical experience to blow the he!! out of a perfectly good theory." --- Lloyd Rosenquist, charter member AWS, 1919. |
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