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NaOH Corroding Metals

  1. Aug 25, 2005 #1


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    Without getting into too much detail on what I am building, here is what I am basically asking,
    Will Soidum Hydroxide (NaOH) corrode brass?
    I am thinking yes. Bras is made up of zinc (which I know NaOH will corrode) and copper (I am not sure about copper).
    Basically, I have a value, made mostly from brass, that I want to use to control the flow of something which will be in VERY Close proximity to a concentrated solution of NaOH. The valve probably has some steel in it too I am guessing.

    So what metals are out, obviously Aluminum, Zinc, ...?
    Are any metals "in"?

    I would probably be better going with a PVC valve, right? But I dont think they are as high a quality as the metal ones, plus I want[ed] to connect the value to a brass hose barb adapter to connect to a plastic tube. I guess I could go PVC all the way.

    Any thoughts?
  2. jcsd
  3. Aug 26, 2005 #2


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    OK, what I ended up doing is trading in all my brass parts for plastic (they call it nylon I think), except for 1 part which I looked and looked and couldn’t find a plastic equivalent for, but this one is either copper or brass, so lets hope it can take it.

    Do you want to know how much of a nerd I am?
    Since it didnt say anywhere whether the metal part I bought was brass or any other metal, and since it looked esspecially shiny and copper like, I decided to test it. So, as all of you know, the most fun way to test what kind of metal something is on a Friday night is of course, find its density.
    Not having a very accurate way to measure volume besides water displacement and that fact that theoretically water weighs 1 g/cc, I found the part to have a density of about 5.5 g/cc, and that is rounding up slitly to make up for the inaccurate volume measurement.
    I looked up the densities of Copper, Zinc, and Brass,
    Cu = 8.92 g/cc
    Zn = 7.14 g/cc
    Brass = about 8.9 g/cc

    So, I found out, assuming my measurements can be taken seriously, that it is made out of none of the above, or atleast is alloyed with a much lighter metal (hopefully now aluminum).
    Last edited: Aug 26, 2005
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