aluminum cast sling shot plaster of paris ?

Discussion in 'Show off your homemades!' started by littlephoenix, Sep 23, 2013.

  1. littlephoenix

    littlephoenix New Member

    4
    0
    0
    hey everyone, im new to this forum, found it via JoergSprave youtube channel..
    so my question is, recently i saw a video online of a very beautiful aluminum cast sling shot this person made, he used plane dirt for his cast, and had to sand down the sling shot quite a bit to get it down to perfection, my question is, why sand? can this method be used with plaster of paris to mold the sling shot much smoother hence shortening the sanding process? or will the aluminum melt the plaster?
    any help would be greatly appreciated :)
    cheers from LA
     
  2. G_Y

    G_Y aiming the less

    383
    0
    0
    molden aluminium has a higher temperature than molden lead, a plaster sprang by casting lead. Would not try it again.
     

  3. Alukuchen

    Alukuchen Senior Member

    277
    0
    0
    I have found the same. Plaster leads to air bubbles and does not let the styrofoam evaporate...
     
  4. Baller-Bub

    Baller-Bub New Member

    127
    0
    0
    I also found plaster to shrink a lot.
    and if its not fully dried, it may explode from
    suddendly steaming the contained water.
    Use the lost foam casting and fine Sand.
     
  5. G_Y

    G_Y aiming the less

    383
    0
    0
    So you did not remove the styrofoam before?
    Read about exploding wax, dangerous in contact with hot metal...
     
  6. Alukuchen

    Alukuchen Senior Member

    277
    0
    0
    That is the essence of lost foam. The model is not removed and disappeares when the hot metal is poured in.
    Doing the same with a wax model would be a bad idea, I guess.
     
  7. EyAlter

    EyAlter New Member

    159
    0
    0
    You could burn it out with gas beforehand.

    Why not mold with epoxy resin and chopped glas fibres? There are also some plastics that you can cast at home. I personally wouldnt want all the hassle dirt and danger of metal casting in my garden.
     
  8. Moin moin,

    if you want to get it right, you will naturally
    Molding sand.
    http://www.flickr.com/photos/[email protected]/

    http://www.flickr.com/photos/[email protected]/9200349415/

    http://www.youtube.com/watch?v=aZcrP8gonAY&feature=youtu.be


    This is Oil Bound sand!

    As an alternative (cheap, but worse) is also quartz sand. Then with a "Lost" blank.

    Think drann is 800 degrees Celsius and more .......

    [ame]http://www.youtube.com/watch?v=0AdJN88l1-0[/ame]

    http://www.ebay.de/itm/10-kg-Formsa...-/190830238860?pt=Figuren&hash=item2c6e5e5c8c

    [ame]http://www.youtube.com/watch?v=jftQjAvlGyA[/ame]
     
    Last edited: Sep 23, 2013
  9. littlephoenix

    littlephoenix New Member

    4
    0
    0
    ok this makes sense, thanks for the great info, so im thinking finer grain sand works best, now will beach sand do the trick or is that not compact enough?
     
  10. Moin moin,

    tight - compact - sand is again not good.
    I did it once with finely ground cement tries (no concrete).
    But here, the air - not escape and exhaust ....

    The best is still molding sand! See my pictures on flicker - the top of the post - before! Here is an aluminum part comes out so that you barely even have to edit!
    Near vision - cost of mass - see E-bay!

    http://www.flickr.com/photos/[email protected]/

    http://www.youtube.com/watch?v=aZcrP8gonAY&feature=youtu.be

    http://www.ebay.de/itm/10-kg-Formsa...-/190830238860?pt=Figuren&hash=item2c6e5e5c8c
    -

    dichter - kompakter - Sand ist auch wieder nicht gut.
    Ich habe es mal mit fein gemahlenen Zement versucht (kein Beton).
    Aber hier kann die Luft - und Abgase nicht entweichen....

    Am besten noch immer Formsand! Siehe meine Bilder auf flicker - oben im Beitrag - davor! Hier kommt ein Alu Teil so raus, das man es kaum noch nachbearbeiten muss!
    Nahteil - kosten der Masse - siehe E-bay!
     
  11. littlephoenix

    littlephoenix New Member

    4
    0
    0
    great info Thorsten, love your flickr images, and the toilet sling LOL
    now where do you guys buy aluminum from that is affordable?