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  1. #1
    Join Date
    Oct 2008
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    Western NC
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    33

    Brazing Question

    I had a little mishap with the suction stub-out on a 1/3hp condensing pkg. My boss says there is no hope for repair and that I should scrap it out, but since I broke it I want to try to fix it. The problem I'm having is with brazing the dissimilar metals. From what I have read on the Sil-Fos site anywhere from a 40% to 56% with flux is reccomended. Does anyone here have experience with brazing steel to copper and what product is best to use. Thanks in advance.

  2. #2
    Join Date
    Aug 2001
    Posts
    116
    Use 45% silver solder (i.e.: Harris Welco® Safety-Silv® 45). Cleanliness is next to Godliness & use flux. Don't recommend sil-fos for brazing non-clad steel.

  3. #3
    Join Date
    Oct 2008
    Location
    Western NC
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    I have 4 sticks of Safety-Silv 56 that I was going to try to use. Which flux would you recommend.

  4. #4
    Join Date
    May 2007
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    Dry as a bone Tucson
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    4,022
    The white stuff
    Some Talk, Some Do
    "keeping condensing pressures low and evaporator pressures high"
    Comfort is my goal
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  5. #5
    Join Date
    Aug 2007
    Location
    Winter Haven, FL
    Posts
    3,584
    I use Lennox Sterling soft solder, with white paste flux. It will join copper to steel, brass and galvanized pipe, (couldnt get it to stick to stainless with white paste flux, but still working on that). If you have overheated the steel then your boss is right.
    You can use a propane/mapp gas torch to join metals with this solder.

  6. #6
    Join Date
    Oct 2008
    Location
    Western NC
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    Will the white flux work with the flux that's already on the Safety-Silv?

  7. #7
    Join Date
    Oct 2008
    Location
    Western NC
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    BTW with my boss soft solder is only used for drain lines. He says that high temp brazing is the only way to go for refrigeration.

  8. #8
    Join Date
    Jun 2006
    Location
    New Jersey
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    4,283
    Quote Originally Posted by tfranchise View Post
    I had a little mishap with the suction stub-out on a 1/3hp condensing pkg. My boss says there is no hope for repair and that I should scrap it out, but since I broke it I want to try to fix it. The problem I'm having is with brazing the dissimilar metals. From what I have read on the Sil-Fos site anywhere from a 40% to 56% with flux is reccomended. Does anyone here have experience with brazing steel to copper and what product is best to use. Thanks in advance.
    This has been discussed alot. If you don't have any experience with brazing steel to copper, then I suggest this. http://www.uri.com/is-bin/INTERSHOP....8AAAEgjiYHFKS0

    It's the easiest thing to use. There are other methods, but if you are not use inexperienced with dissimilar metals, it's the quickest and painless.

  9. #9
    Join Date
    Oct 2008
    Location
    Western NC
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    Those are exactly the ones that I have, except I have the 56% not the 45%. With those is flux still required?

  10. #10
    Join Date
    Jun 2006
    Location
    New Jersey
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    4,283
    Quote Originally Posted by tfranchise View Post
    Those are exactly the ones that I have, except I have the 56% not the 45%. With those is flux still required?
    No the flux is on the rod. But to make is easier, just make sure the joints are clean.

  11. #11
    Join Date
    Aug 2007
    Location
    Winter Haven, FL
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    3,584
    Quote Originally Posted by tfranchise View Post
    BTW with my boss soft solder is only used for drain lines. He says that high temp brazing is the only way to go for refrigeration.
    I remember working for dolts like that. I made a copper "square usint 3/4 soft tubing and elbows. Pumped it up to 900 psi of nitro. I told him when the joint breaks, feel free to fire me, was eventually fired, but not for the joint breaking.
    Using 95/5 or sterling is a good way to keep from burning txv's and some other components that have nylon inside.

  12. #12
    Join Date
    Oct 2008
    Location
    Western NC
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    33
    We have had alot of discussions at school on the soft solder vs brazing issue. Seems to me its a personal preference although I don't have enough experience to have formed an educated opinion.

  13. #13
    Join Date
    Jun 2006
    Location
    New Jersey
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    Quote Originally Posted by tfranchise View Post
    We have had alot of discussions at school on the soft solder vs brazing issue. Seems to me its a personal preference although I don't have enough experience to have formed an educated opinion.
    All I got to say is what manufactures uses soft solder on the coils?

    And manufactures are the cheapest.

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