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Thread: Brazing Question
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05-13-2009, 08:27 PM #1
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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.
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05-13-2009, 08:39 PM #2
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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.
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05-13-2009, 09:23 PM #3
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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.
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05-13-2009, 09:30 PM #4
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05-13-2009, 09:36 PM #5
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.
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05-13-2009, 09:41 PM #6
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Will the white flux work with the flux that's already on the Safety-Silv?
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05-13-2009, 09:43 PM #7
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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.
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05-13-2009, 09:44 PM #8
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.
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05-13-2009, 09:48 PM #9
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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?
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05-13-2009, 09:51 PM #10
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05-13-2009, 09:53 PM #11
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.
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05-13-2009, 10:00 PM #12
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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.
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05-13-2009, 10:02 PM #13


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