Brazing 6" Copper pipe for domestic water line
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  1. #1
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    Default Brazing 6" Copper pipe for domestic water line

    I have a project coming up at work replacing a 6" 90° and two couplings. I have done a good amount of brazing in the past, but only up to 3" copper. I've been told a Rose bud tip is the required tip for the job, however I'm unclear if this is accurate. I would like the advice of someone who has brazed sizes this big as to tip selection and size. I'm excited to tackle this, and dont want to screw it up by using an improper amount of heat. Any information from one who has such knowledge would be awesome!!

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    Actual brazing, or soldering with a potable water approved solder? Were you given specs for the solder/braze?

    Copper & the Environment: Drinking Water Plumbing Systems [safe solder]

    With something that big a good size rosebud would be helpful, but even better might be two and a helper (as long as you're communicating well and not frying each other).

    Are you doing it in situ, or on a bench, then the couplings are used for installation? If doing it in place, be damn careful, have some thin sheets of stainless steel at hand to act as thermal protection, and maybe some fiberglass batting behind them for extra security.

    [All advice worth what you paid, no liability assumed]

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    get some ceramic fiber insulation.. its like 6$ a square foot for 1" thick on ebay. good to 2400F. will reflect most of the heat back at the pipe.

    a carefully insulated copper pipe can be brazed with a propane torch, where as in open air it isn't possible to get it red hot unless the flame envelops the pipe for at least 1 pipe diameter.. which for 6" pipe would require on the order of 3 propane weed burners.. and copious space around the pipe for the flames.

    with oxy you can get something like 24KW per square cm of heat transfer from the flame, which should be possible to braze 3/16" thick copper without preheating, but i have no experience with that. if you can preheat the pipe to 500F or something it may go a long way to making the job a lot easier.

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    if doing a brass filler braze,be very careful as copper will melt as well very easily ....because the brass will dissolve the copper into a lower MP brass.....Id certainly be using the correct plumbers silver solder......leaching the zinc from a brass braze would also be very likely with some kinds of water....see dezincification.


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