hydrogen purged furnace for silver brazing ?

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I am in central florida-   I have a diffusion pump body which is a steel can about 10 inches across and about 14 inches tall.  It has a copper coil wound around it in the outside which I feel sure was oven applied silver solder (high temp).  The copper is bad and needs to be replaced.I have been told that the best method is to use a hydrogen purged heat-treating type furnace to do the job.I can not find anyone with a furnace that can do this.   Does anyone know a place with a furnace like this that it would fit into ???????  (if I cant find anyone- I was going to try to Tig it on by using silicon bronze rod  in stead of silver solder-  )Some where in florida would be good- but anywhere it can be shipped would  possibly work.......Thanks in advance !Tim
Reply:I dont know but why cant you silver TIG?
Reply:Whats your dimensions of the the diffusion pump?
Reply:I think I can probably Tig in the silver solder too- but I havnt tried it yet-   I have tried the silicon bronze.The dimentions are in the first post.....T
Reply:Originally Posted by jethroI think I can probably Tig in the silver solder too- but I havnt tried it yet-   I have tried the silicon bronze.The dimentions are in the first post.....T
Reply:How are you going to heat the Diffusion pump? Electricity (3 phase) or gas ? AIRCO power supply the for arc?Last edited by Insaneride; 01-19-2014 at 10:30 PM.
Reply:hydrogen burns real good, HindenburgDo you mean nitrogen or argon ?
Reply:It is an existing varian diffusion pump.   Its the outer body of the pump- which is a steel tube with an outer wound copper cooling coil.   I called several heat treating places and several said for silver solder that hydrogen would make the silver solder flow better than argon.  I would have guessed argon.  T
Reply:I would have guessed OA for silver solder. It sounds like you need a new DP otherwise, why dont you TIG it? The DP oil needs to be hot enough to vaporize and for cooling; cool enough to liquify the oil. Do you really need a hydrogen furnace to attach copper to the steel?BTW, Hydrogen wont ignite in a vacuum. You need oxygen for hydrogen burn. Without oxy, how would the hydrogen make water during the explosion? :laughing:
Reply:You HAVE to be talking about helium, NOT hydrogen! Heat hydrogen in a furnace and real bad things will happen!metalmagpie
Reply:Hundreds of H2 furnaces run every day in the US, almost never have a problem.  The trick is to keep the O2 content damn low, usually PPM levels.  There will generally be a bunch of N2 for inlet/outlet curtains.  The atmosphere inside the furnace can range from 1-2% H2 all the way up to 100%.  Look up H2 furnaces, endo and exo generators, disassociated ammonia atmospheres for the interested readerhttps://www.crystec.com/kllhyame.htmhttp://www.samgasplants.com/endo-and...enerators.htmlhttp://www.franklinbrazing.com/capab...ainless-steel/Experience is something you get right after you need it
Reply:I see plumbers using MAPP or acety with a turbo torch on copper with silvaloy. I would think that an OA torch and lots of white flux would work on copper to steal. Why do you have to use a hydrogen furnace? BTW, Ive never had to repair cooling lines for a DP but Ive been inside of DP's (7ft tall x 4ft) and have torn the jets down for cleaning and straightning several times. I even set a record of the most rebuilt pumps (4) in one shift.
Reply:Originally Posted by InsanerideI see plumbers using MAPP or acety with a turbo torch on copper with silvaloy. I would think that an OA torch and lots of white flux would work on copper to steal. Why do you have to use a hydrogen furnace? BTW, Ive never had to repair cooling lines for a DP but Ive been inside of DP's (7ft tall x 4ft) and have torn the jets down for cleaning and straightning several times. I even set a record of the most rebuilt pumps (4) in one shift.