Tig Brazing ?

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I visited a friend yesterday and we were discussing suspension component fabrication.  He then explained to me that he had been recently introduced to Tig brazing.  He stated that he had fallen in lovewith the process and was now using it regularly to fabricate mild steel, tubularsuspension pieces.I eventually asked him questions about the overall process, but his knowledge was very limited or he just didn't feel like talking . So.... I would greatly appreciate any info that anyone can provide.-  What machine settings are generally used (AC, DC...etc) ?-  Torch setup (tungsten type.....) ?-  Filler wire used (Did Everdue ring a bell ?, bronze type filler ) ?-  Overall process ? (don't puddle the base metal ? )Thanks in advance-Cheers !P.S. I did search for this topic thru the forums and didn't find much info-Graham-Mechanical EngineerAutosport Mechanic/Fabricator
Reply:When I took welding classes it was a process we played with. I tig braze perforated steel to stainless for the mufflers I make. And use it to attach that piece inside the muffler body. Since you dont need as much heat there is almost no chance of carbide precipitation on the outside of the muffler.Use the same settings as you would for tig welding. Just back off a little as it does not take as much heat as tig welding. The filler used is ERCUSI. http://store.weldingdepot.com/cgi/we...B0xxx36-1.htmlIts a process to have in your bag of tricks. Dont know if I would make suspension pieces using this filler but it is pretty strong.mm135HTP Invertig 201 With water cooler9" Southbend LatheLots of hand tools.
Reply:I have been tig brazing stuff for at least 20 years now. Its a great process, and its actually very forgiving.I usually use DC, but I once took a class from Ron Fournier, who is one of the best metal workers on the planet- and he used AC, with HF, to tig braze, and it worked great.I use "everdur" rod, which is just a trade name for Silicon Bronze filler rod. Some places sell "everdur" brand, but most any welding supply will have Silicon Bronze.No big deal with settings- I run it a bit lower on the amps than welding, as you are not melting the parent metal, but with a foot pedal, its not too fussy.I just run 2% tungsten for everything, so thats whats on the machine when I tig braze, and it works fine.Just try it out- you get the base metal hot, but not melted, and then add silly bronze filler wire to it. The silly bronze kinda "jumps" when it gets hot, so you actually usually add a bit at a time, and work your way along- try it, you will see.We use it for things like welding 24 gage sheet metal leaves onto 3/8" round bar candlesticks- its great for thick/thin stuff, as you puddle the bronze on the big piece, then work it onto the thin stuff.But it works well for dissimilar metals as well- Silicon Bronze will actually tig braze cast iron, or stainless, or most bronze and copper alloys, to themselves, or each other. I have brazed stainless to bronze with it, or stainless to mild, or cast to bronze.Its a really great rod to have in the shop, solves a lot of problems.
Reply:Tig brazing works well with a variety of materials.  We have a part that we make for the aerospace industry that is vacuum furnace brazed with a pre-placed paste.  It's a nickel braze alloy.  Per specification, if, after the run, there are voids of a certain size, we just tig braze them with soild wire of the same alloy.  Actually, it's just like tig welding, just not as hot, and no flux cuz you got shield gas anyway.I r 2 a perfessional
Reply:Just remember, if its TIG brazing, the base material shouldn't be melted, so you'll be using far less amperage than you would on your normal settings.I used it quite a bit while doing chassis work.  1/16 everdur is fantastic to work with when doing sheet metal work.  Because of the sensitivity of the 4130 tubing, I'd drop the amps waaaay down, and "TIG braze" things like the sheet for the firewall to the tubing.  No loss of strength from drilling 1000 rivet holes in the tube, and its very fast and clean.
Reply:If the base metal steel is melted, would the filler not start to pull iron from the steel significantly weekening the join?So the key to making this work then is less concentraited heating to get surrondings hot enough to flow filler, but not melt base metal, any advantage to a blunter electrode point?
Reply:If you heat the parent metal too much the Silicone Bronze will boil. And when it does it spits like a rabid dog
Reply:It is called brazing when you are adding a second type of metal to the parent material.If your are TIG welding bronze with silicon bronze filler it is still TIG welding NOT brazing.AWS certified welding inspectorAWS certified welder
Reply:Don,Adding a 2nd type of metal to the parent metal can also be referred to as welding.It is called brazing when each of the following criteria is met:1.  The parts must be joined without melting the base metals.2.  The filler metal must have a liquidus temperature above 840 degrees F (450 C)3.  The filler metal must wet the base metal surfaces and be drawn into or held in the joint by capillary action.Those are the only criteria."Preface to the AWS Brazing Handbook, Fourth Edition."I r 2 a perfessional
Reply:Originally Posted by kbnitDon,Adding a 2nd type of metal to the parent metal can also be referred to as welding.It is called brazing when each of the following criteria is met:1.  The parts must be joined without melting the base metals.2.  The filler metal must have a liquidus temperature above 840 degrees F (450 C)3.  The filler metal must wet the base metal surfaces and be drawn into or held in the joint by capillary action.Those are the only criteria."Preface to the AWS Brazing Handbook, Fourth Edition."
Reply:It can be a handy trick to have around. I agree with papasloan. I've brazed a lot of stuff and some of it takes tremendous loads, but they aren't shock type loads. I wouldn't use it on suspension components, but that's just me.The difference between art and craft is the quality of the workmanship. I am an artist.
Reply:Cool concept ,I have done tons of torch brazing and silver solder (oxygen piping) jobs but this idea is so simple and you could really eliminate HAZ problems with GTAW. Do you think it would work with fluxed brazing rods as well say for grey nodular cast iron?
Reply:No, fluxed coated rods do not work for tig.  You can get by if you have to by cleaning the flux off but avoid it if possible.Ive used the stuff mainly on galvanized, you can run it cold enough to not burn up the coating.  No fumes, no residue, no loss of corrosion protection.Have we all gone mad?