Thanks Kelly...first time foam

Discussion in 'Lost foam casting' started by Mach, Jun 11, 2018.

  1. Mach

    Mach Copper

    Tried out foam for the first time on some freezing block for an old GE monitor top refrigerator. Turned out better than expected. Some porosity which I'm assuming is pouring too hot but otherwise I'm happy. Thank you Kelly for all the posted guidance.

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    Foam blanks ready for casting. I experimented with a laser etched logo on hardboard dipped in acetone and then pushed into the foam. It worked ok given the method.
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    Laser cut profiles for the foam cutter.
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    I used the instructions at: http://www.rcsoaring.com/rcsd/RCSD-2008-11.pdf
    to build my hot wire cutter (page 101).
     
    oldironfarmer likes this.
  2. Al2O3

    Al2O3 Administrator Staff Member Banner Member

    Nice job Mach. Very interesting method you developed for applying the logo. Hopefully it is the first of many more successes yet to come.

    Best,
    Kelly
     
  3. oldironfarmer

    oldironfarmer Silver Banner Member

    I'll second my thanks to Kelly for his well written guidance. I've had better experience with lost foam than I ever dreamed and use it as a regular tool.

    What material did you use and what did you heat it with? It is a lot of porosity.
     
  4. Mach

    Mach Copper

    I used wheelium purchased from Art over at AA. It was heated with natural gas but I was screwing around with different blowers. I've got a problem with the flame burning back into the tuyere and was trying to upsize the blower while it was melting so several starts and stops.
     
  5. Al2O3

    Al2O3 Administrator Staff Member Banner Member

    Regarding porosity, higher pour temps, extended melt times, rich furnace atmosphere will contribute to porosity. Same goes for the more times metal is re-melted, especially without de-gassing. Sprues and heavy sections are the most likely areas for porosity to reveal itself. The surface of the part looks pretty much like the pattern. I presume it was coated with something like drywall mud....yes?

    For me, it depends on what the part is as to whether I degas. For decorative or ornamental parts, no, unless it is going to get polished.

    Best,
    Kelly
     

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