Ceramic Shell with a twist..

Discussion in 'Investment casting Ceramic shell method' started by mytwhyt, Sep 24, 2021.

  1. mytwhyt

    mytwhyt Copper

    I'll start with a few castings done on AA.. Was into skulls at the time these were done.. A different type ceramics, but still by definition, ceramics.. Starting with two coats of Drywall mud.. One brushed on, the second dipped, or poured over the mold, including a hollow pour cup.. After they are dry, a layer or two of fiberblanket saturated with silicon dioxide..
    Thin mold melts surface before the wax expands.. Now what happens with the mud prevents any cracking.. The drywall mud is still absorbent and sucks up the melting wax negating expansion of the wax.. A couple mm of compressed blanket stops any leakage on metal.. In the second pic, only one of the waxes has fiber blanket coating. Will follow up with the ashtray mold pics.. IMG_2509_zps79ddaa59.jpg IMG_2514_2_zps49c2333a.jpg cooler037_zpsc381861c.jpg cooler045_zps59274efb.jpg 8c96fad0-a21d-4f8f-a6f1-cd1d9bcb7af5_zps589b8eff.jpg 8d76caa9-9adb-49ee-8aea-c3d3b30f5fd9_zpsb1870968.jpg
     
  2. theroundbug

    theroundbug Silver

    Awesome. I tried this with pla. Cracked before it even reached 500°
     
  3. mytwhyt

    mytwhyt Copper

    Coated this wax with mud yesterday.. Hung in the shop overnight, humidity about 15%.. Started with the SS and chem bond 10 mix about 2pm.. Pre cut the blanket for both sides... First side was a bit thicker than I wanted.. A little more than a mm thick compressed between thumb and finger.. I'll be giving a second layer of SS and blanket tomorrow.. Gave it a light brush with some 80 grit.. Not near as bad as fiberglass, but some ss needles as it hardens....
    The first 2 are double coated with mud.. The third pic has the front side done, with the back side waiting to be done.. Last two pics done.. Took about 30 minutes and the SS began to kick.. Used 280 grams SS and 31 grams of Chem bond 210... Didn't put the blanket on the scale.. The wax and coatings come in at 280 grams. The wire I used to hang the wax with will be cut off and left in the casting.. Next light coat overall, I'll trim the pouring cup next.. I'm rather pleased it went as smoothly as it did.. To make it even easier, cold water rinse to clean up, and no smell.. The only thing that can make it better is if it works....


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    Last edited: Nov 5, 2021
  4. mytwhyt

    mytwhyt Copper

    The layup has hardened, but not as much as it will as it loses more water content.. Keeping the mold at 80*f with air flow.. I have an old pressure cooker that the mold can fit in.. Next mold, I plan on using the p cooker at this point .. First put the mold in pc, pull out the air, and flood back with co2..
     
  5. Jason

    Jason Gold

    Sounds complicated... Did it work?o_O
     
  6. mytwhyt

    mytwhyt Copper

    The molds nice and dry now.. Just haven't reworked the oven.. I over fired some glass and took out my oven floor.. I'll redo the floor with perlite and SS.. This will be the second time. This is the finished skull casting..

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  7. Jason

    Jason Gold

    yeah glass is murder. I've got a special furnace I use only for glass.
     

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