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Re: Investment casting of steel

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  • halfvw
    Call some custom gun smiths? You might find one that can make these small parts and have the casting equipment already on hand as this sounds just like some
    Message 1 of 92 , Oct 25, 2009
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      Call some custom gun smiths? You might find one that can make these small parts and have the casting equipment already on hand as this sounds just like some investment cast gun parts.

      And as others have pointed out - neither alloy is "mild steel".
      ======================
      Leon McAtee

      --- In hobbicast@yahoogroups.com, "r_e_dorsey" <r_e_dorsey@...> wrote:
      >
      > I want to cast 4140 and 6150 steel. Both mild steels. The problem is I only need a dozen parts cast at a time and they are quite small. A foundry doesn't want to bother with it. Is this something a jeweler could do since the parts are small (0.5oz)?
      >
    • CaptonZap@aol.com
      In a message dated 11/29/2009 8:17:11 AM Mountain Standard Time, beach.buggy@tiscali.co.uk writes: hi the pump is a gast manufacturing diafram pump the specs
      Message 92 of 92 , Nov 29, 2009
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        In a message dated 11/29/2009 8:17:11 AM Mountain Standard Time,
        beach.buggy@... writes:

        hi
        the pump is a gast manufacturing diafram pump
        the specs say 60 psi 29"hg but the guages have not been calibrated
        i might be able to get this done at work this week
        do you think it should be ok

        barry




        --------------------------------Reply-------------------------

        Diaphragm pumps are not know for high vacuum, and they are typically rated
        optimistically. Then, as they age, their diaphragms start leaking, and their
        performance suffers. Also, as your elevation increases, the vacuum you can
        pull goes down, and the gauges read higher.
        I am at 5300 feet, and on a good day, I may pull 24 inches Hg, with a
        refrigeration pump.
        The gauge could also be a cheap one, and its accuracy suspect.
        You best bet is to suck from a tank, which is plumbed to the chamber,
        through a valve which is closed while you pump down the tank. When you cast, open
        the valve, and you can get a higher vacuum for a longer period of time,
        until the tank and pump equalize. A 30 lb refrigeration tank is a starting
        size. A 50 lb tank would be better, but they are harder to find. A 20 lb propane
        tank has plumbing that easier to deal with, but they should be cleaned
        thoroughly of all oils and residues, which is a chore.
        I drill a hole in the top of a tank, and braze a 1/4 in pipe coupling over
        the hole, and plumb from there with a tee, and hoses to the chamber and
        pump. CZ


        [Non-text portions of this message have been removed]
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