solder not taking to copper

Old 12-24-06, 03:42 AM
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solder not taking to copper

In advance, excuse my ignorance- this is a whole new ballgame to me!
My buddy and I are renovating an old (1958) single story crawlspace house that I purchased for my family. He is showing me how to solder, and we installed a new water heater and are in the process of replacing all of the old fixtures and valves inside and outside of the house.
We have come across a 1/2" copper pipe on the house that is not taking the solder. It is being thoroughly cleaned and fluxed, but when the right temperature is reached the solder balls up and rolls off and is not being wicked into the join.
Why would this happen? All of the other pipes have sucked up the solder just fine. Any ideas why this would happen?
Thanks in advance-
Old 12-24-06, 04:37 AM
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Only two things that I can think of of the joint is clean. Either you're getting it too hot or there is water in the pipe.
Old 12-24-06, 06:19 AM
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water in the pipe , open the lowest outlet in the house to drain , in my case its a hose bib outside
Old 12-24-06, 06:23 PM
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I too, have ran into old red hard copper, not brass, that does what you describe. More heat is not the answer.

You need to "tin" the copper tubing. Without any fittings but just a plain, clean pipe end; flux the pipe, heat it up and then just touch the solder to the pipe. A small amount of solder 'fix' itself to the pipe and you can solder to this. You don't need it to run around and form a ball on the bottom of the pipe as this would need to be removed to get the fitting on the pipe.

After tinning the pipe, you can solder just like normal.

Hope this helps and merry xmas to everyone...

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