Filament that disolves on heat?

Discussion in 'Filament' started by Julian64, Oct 21, 2016.

  1. Julian64

    Julian64 Active Member

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    Hi

    Just wondering if anyone knows of a filament which would work for lost mold work.

    I'm currently printing out PLA, then making a greensand mold, followed by extracting the PLA and pouring in aluminium.

    I was just wondering if anyone knows of a filament which would disintegrate sufficiently at that sort of temp to allow more complicated molds
     
  2. Falc.be

    Falc.be Well-Known Member

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    If im not mistaken those peel away support filaments are pretty usefull for that since they are porous
     
  3. Kanedias

    Kanedias Well-Known Member

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    I'm planning to try PLA in casting plaster - leaving the plaster mold upside down in a 120 degree oven to remove the PLA. It'd also help cure the plaster at the same time.

    There are filaments designed for casting. Ones called mold lay but there are others. I haven't tried them.

    I too have been using greensand with varying results.
     
  4. GBR1

    GBR1 Member

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    You mean some thing like this:)



    GBR1
     
  5. wfredette

    wfredette Well-Known Member

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    I had decent results with casting aluminum in a "lost PLA" mold. I printed the model in PLA, then invested it in a mixture of plaster of Paris and playground sand. When the mold had dried, I burned it out in a homemade gas forge that I made from a small ash can lined with a mixture of furnace cement and perlite. The PLA burned out completely, and I used a short blast of compressed air to blow out any residual ash, though I don't think there was much. Some photos of the process:
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  6. Henry feldman

    Henry feldman Well-Known Member

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    Really cool. About what size surface feature can you resolve like this?
     
  7. wfredette

    wfredette Well-Known Member

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    That's a good question. This wasn't a highly detailed model, and it was pretty coarsely printed (I think 0.3 mm layer height) because the whole thing was an experiment. If I had had a better way to vibrate out all the bubbles, that would have helped, too. But in this detail photo taken just at it emerged from the mold, you can clearly see that the layer lines, and some of the layer change zits were preserved in the casting:
    [​IMG]
     
  8. Kanedias

    Kanedias Well-Known Member

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    I haven"t tried the lost PLA cast yet but using prints as molds in greensand has worked pretty well

    image.jpeg
     
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