[Jewelry making - Article 00172] - [Orchid] Casting problems with R&R investment

[Lee Epperson]

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    OK fellow casters. I ran into a problem today and I am not sure what
    the resolution is. 

    First I will describe my normal process: 

    I normally use Ransom and Randolph investment. I mix, vacuum, pour
    and vacuum within a 7 minute period. I quench my 2-1/2 inch flasks
    in about 6-7 minutes. I enclose the flasks in a larger flask to
    prevent fire scale. It takes slightly longer for the flasks to cool
    when encased in a cover flask. Normally I would quench in 4-5 minutes
    if I didn't enclose the hot flask with a cover flask. 

    Here is the problem: 

    I was out of my Ransom and Randolph investment and _HAD_ to cast
    Sunday and Monday. My local supplier was out of 100 pound boxes of R
    & R investment. He said he had several 10 pound containers filled
    with the last of his R & R. He had not scheduled a new delivery
    because of inventorying the store. He claimed he refilled the 10
    pound containers recently from a fresh 100 pound box. 

    So far so good. That is until I started mixing the new investment. I
    noticed several things that were different from R & R. 

    1. The normal R & R mixing ratio produced a much thinker mix. R & R
    claims that their mix is thinner than other investment. Their water
    to investment is greater that other products. 

    2. I normally pour my mixed investment through a kitchen strainer to
    insure I eliminate all clumps that might exist. This new stuff would
    not go through the strainer. 

    3. The mix seemed to set up faster. 

    4. I lived with these problems and invested several 4" 5" and one 6"
    flask and several 2-1/2" flasks. But when I quenched the castings I
    could hardly remove the casting from the flasks. The investment did
    not break apart like R & R does. It was like concrete. I spend 10
    minutes digging a simple casting out of a 2 1/2" flask. With R & R my
    castings come out of the flask in a minute or two. 

    I cast outside and Phoenix is not known for cool summer temperatures.
    The temperature in me casting area with two burnout ovens going is
    118 degrees. Needless to say taking 10 minutes digging a casting out
    of a flask in that temperature does not lead to a happy camper. 

    When I bought the stuff the dealer swore that the investment was
    R&R. When I called him today to complain about the investment he
    said maybe the investment was Satin Cast 20. 

    My question to all of you who use Satin Cast 20, do you have that
    much trouble getting castings out of the flasks and if so why do you
    use Satin Cast 20. 

    I once used some investment that has some fibers in it. I remember
    that I had the same trouble with that stuff. 

Any ideas?

Thanks,
Lee Epperson the anti-fire scale guy.
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