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  1. #40
    Join Date
    Feb 2013
    Location
    Phoenix, AZ
    Posts
    198
    Here's a reference for purity levels for various grades of CO2 (from the same company hvac5646 used). It lists welding/industrial grade CO2 as 99.8% pure, and less than 32ppm H2O.

    http://www.abbottwelding.com/index.p...urity%20Levels

    CO2 is NOT an inert gas as some have stated. At least at steel welding temperatures it is known to react with the weld puddle, causing embrittlement. Not saying that it would be inappropriate as a braze-purge though.

    I would like to see a comparison of brazed joints (cut open) using N2, CO2, and no purge gas (not open tubing like I have seen on YouTube, but with ends nearly sealed, just enough to allow pressure to escape but not allowing free flow of air). I am not aware of any published tests thus.

  2. #41
    Quote Originally Posted by DDC_Dan View Post
    Here's a reference for purity levels for various grades of CO2 (from the same company hvac5646 used).
    It lists welding/industrial grade CO2 as 99.8% pure, and less than 32ppm H2O.
    To be clear, the reference was only for Nitro. This is not the same company reference the Boss uses to buy our dry co2.
    http://www.abbottwelding.com/index.p...urity%20Levels

    CO2 is NOT an inert gas as some have stated. At least at steel welding temperatures it is known to react with the weld puddle, causing embrittlement. Not saying that it would be inappropriate as a braze-purge though.
    Gafadlefarb! Co2
    is the end of the combustion process. It cannot not be broken down further unless improbably high pressure and temperature are applied to it; coCOnditions you would never see in naturally occurring events. That is the definition of an inert gas,


    I would like to see a comparison of brazed joints (cut open) using N2, CO2, and no purge gas (not open tubing like I have seen on YouTube, but with ends nearly sealed, just enough to allow pressure to escape but not allowing free flow of air). I am not aware of any published tests thus.
    CO2 not being an inert gas is the biggest mis- conception that comes up when the topic of using dry CO2 is raised

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