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Thread: what did you do in your foundry today?

  1. #4621
    Senior Member Toolshed's Avatar
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    Jeff, That is EPIC!!!! Dude, such good work!
    "If you work with your hands, you’re a laborer.
    If you work with your hands and your mind, you’re a craftsman.
    If you work with your hands and your mind and your heart, you’re an artist."

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  2. #4622
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    Today I did something different. I put two waxes into the same investment. I could have joined them, but I would have had to use the #30 crucible and the large furnace. This way I used the #8, poured one, melted some more bronze, and poured the other.



    Tomorrow I'll bust it open and see what I have.

    Richard
    When I die, Heaven can wait—I want to go to McMaster-Carr.

  3. #4623
    Senior Member Zapins's Avatar
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    Interested to see how that worked out Rasper. That would be a time saver for sure if you could do multiple pours in the same mold.

    I'm gearing up for a huge casting session this thursday or friday (hopefully). Going to cast 11 molds, hopefully in one day. I might burn them all out first and cast them all the second day. Make sure the shells are all clear of debris when cool enough to handle and not cracked first before pouring.

  4. #4624
    Quote Originally Posted by Zapins View Post
    I'm gearing up for a huge casting session this thursday or friday (hopefully). Going to cast 11 molds, hopefully in one day. I might burn them all out first and cast them all the second day. Make sure the shells are all clear of debris when cool enough to handle and not cracked first before pouring.
    I didn't know it was okay to burnout, allow it to cool, reheat and pour. Learn something new everyday!
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  5. #4625
    Senior Member Zapins's Avatar
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    With ceramic shell it is ok to cast after burning out the molds (I found that out from a foundry in Philadelphia a few years back). You just need to make sure they get back up to pouring temperature before pouring or there is a risk of premature freezing or possibly cracking.

    Cooling down molds lets you shake them around by hand (gently) and listen for broken bits and dust that sometimes dislodges inside during burn out and can cause casting defects if not shaken out. This is hard to do when the shells are hot!

    I'll see if I can set up my camera to record when I finally end up casting. I am recovering from a nasty head cold so I didn't manage to start coating the waxes today like I had wanted to.

    I hope I can get my new wax burnout kiln up and running for this casting session. I either need to get my pressurized oil burner up and running for the first time (as if I could be so lucky to get it working on the first run), or I need to build a second propane burner and hook it up. Also a decent bit of welding that needs to be done to finish it up.

  6. #4626
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    The double pour mentioned above in last night's post
    worked out well.




    I took the first batch of metal, for this head, to 47 millivolts on my pyrometer. After deducting the
    allowance for the temperature of the meter, the metal
    temperature was right at 2020 F. I measured that right
    after I opened the furnace and before I skimmed the
    melt. The crucible sat in the furnace for several minutes
    and I figure it picked up a bit more heat during that time.










    I was afraid I had poured the head a little too cold so
    I poured this one hotter than the head.

    Look at the surface finish on the head, and then look at
    the surface on this one.
    When I die, Heaven can wait—I want to go to McMaster-Carr.

  7. #4627
    Senior Member Zapins's Avatar
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    That is very interesting. So the hotter pour gave a burnt rough finish and the colder pour gave a better one.

    I always get a finish like the torso. Burnt and a lot of clean up to do. I don't measure temperature and just eyeballing it.

    I will try get my temperature probe working. What temperature do you think is ideal for everdure?

    Do you have a K type probe?

  8. #4628
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    It appears that anything over 2000 F. causes some sort of reaction. I have assumed it is with the plaster. C.W. Ammen in his bopk, Lost Wax Investment Casting, says don't pour at more than 2000 F. as well.

    But I believe you are a ceramic shell man. If your Everdur castings in ceramic shell molds are doing the same, then my idea about the reacting plaster may be wrong.

    You should make a pyrometer. Here is a tutorial I wrote up several years ago that is a complete guide to making a cheap and long lasting K type pyrometer.

    http://www.alloyavenue.com/vb/showth...se-a-Pyrometer
    When I die, Heaven can wait—I want to go to McMaster-Carr.

  9. #4629
    Senior Member Zapins's Avatar
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    Must just be a property of bronze then to form firescale when poured hot. I have often wondered what caused that issue because it creates hours of sanding and polishing to get rid of it.

    I looked through that tutorial and made one already but I was having issues with the thermocouple meter I bought from ebay. It is supposed to convert the voltage into a temperature but instead seems to play games. I haven't tried it with a volt meter but I will on Thursday or Friday when I do my melt. What temperature does everdure solidify and how much time do you have before it cools from 2000f to solid? Do you always pour at 2000?

  10. #4630
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    I use five dollar multi-meters from Harbor Freight. They have a limited lifespan so I buy a handful at a time. Why complicate things. All I do I guess the temperature of the meter and subtract that from the reading it gives to get the actual temperature of the melt. The temperature of the meter is not the ambient temperature at the furnace, but the temperature at my workbench where the meter has been sitting for hours.

    2000 F. seems to be plenty hot for Everdur when poured into a hot mold. I figure the interior of my molds are 800 F. when I pour them.

    Here is what Atlas metals says about Everdur. I would assume these figures are for pouring into sand.

    Melting Point (Liquidus) 1790
    Melting Point (Solidus) 1590
    Pouring Temperture (Light) 2000 - 2150
    Pouring Temperture (Heavy) 1850 - 1950
    When I die, Heaven can wait—I want to go to McMaster-Carr.

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