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  1. #1
    Join Date
    Jul 2004
    Location
    Oakland, CA
    Posts
    54
    Trying to brazing a steel to copper connection, do I have to use a kind of flux or is correct do it as a copper to copper?. I use oxi-acetylene torch, and use silfox solder.

    Thanks for comments.

  2. #2
    Originally posted by lmtd
    It is NOT correct to do it as copper to copper.

    Clean it REAL GOOD, don't touch it or blow on it, silver paste flux and 35 or 45% brazing wire. I like the 45% myself.
    AMEN!


    Use the search feature here to see more threads where this topic is discussed to the nth degree!

  3. #3
    Join Date
    Sep 2004
    Posts
    523
    I have had the best results with paste flux and 45% silver solder.Make sure your copper and steel are real clean then get your tubing warm with your torch and apply your flux.I never had good luck applying the flux to cold metal.Keep most of your heat on the copper when it starts to flow move your heat towards the steel this will draw the solder up into the joint. Watch out and don't let the steel get cherry red.

  4. #4
    Join Date
    Oct 2004
    Posts
    3,400

    Practice on scrap.

    Originally posted by josan6
    ...brazing a steel to copper connection...
    Silphos contains phosphorus.
    Phosphorus is not intended for use with steel.
    It might stick to steel, but it causes the steel to become brittle. It's a leak, waiting to happen.
    Use 45% instead, with the proper paste flux.

    Clean everything.
    Keep excess flux out of the system.
    Coat the tube & fitting with flux, then slip it together.
    (Part of the job of the flux is to protect against oxidation while heating.)
    Watch the flux. It will indicate temperature.
    At 212, the water boils out and the flux becomes dry. Keep heating, slowly.
    When the proper temperature has been reached, the flux will turn clear & quiet.
    Don't overheat.
    Practice, practice, practice, on some scrap.

    (Sorry, R12rules, I did a search & many, many unrelated threads showed up.
    Including, "Who wants to argue with me?".
    I thought I might help Josan6 narrow it down a little.)

  5. #5
    Join Date
    Mar 2004
    Location
    NJ
    Posts
    1,214
    Originally posted by fixerup
    I have had the best results with paste flux and 45% silver solder.Make sure your copper and steel are real clean then get your tubing warm with your torch and apply your flux.I never had good luck applying the flux to cold metal.Keep most of your heat on the copper when it starts to flow move your heat towards the steel this will draw the solder up into the joint. Watch out and don't let the steel get cherry red.
    Thats the real trick to it i think.
    thehumid1-------I live in NJ, a state where it's free to come in but you have to pay to leave!

  6. #6
    Join Date
    Oct 2003
    Posts
    566
    all good advice, don't touch it because of the oil on your skin...will screw the whole thing up...
    Hey mosquito, quit biting (slap!!) me... ©
    Anyone like Josey Wales?
    C'mon, you know I'm right!

  7. #7
    Join Date
    Jan 2004
    Location
    Earth
    Posts
    4,879
    Stay silv 45 comes in sticks with the flux on it. I’ll never go back to coils of silver again. That stuff is great.
    A Diamond is just a piece of coal, that made good under pressure!

  8. #8
    Join Date
    Jul 2000
    Location
    Guayaquil EC
    Posts
    10,487
    Originally posted by frozensolid
    Stay silv 45 comes in sticks with the flux on it. I’ll never go back to coils of silver again. That stuff is great.
    I've used those blue flux-coated sticks for a couple of years now. I love them, too. I still have the wire and paste flux in the truck but I can't recall when I used it last.

  9. #9
    Join Date
    Aug 2002
    Location
    manitowoc wisconsin
    Posts
    4,943
    colored pictures too.. http://www.jwharris.com/jwref/procs/
    Take your time & do it right!

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