Results 1 to 10 of 10

Thread: Casting Advice

  1. #1
    Junior Member
    Join Date
    Mar 2017
    Location
    South Central Texas
    Posts
    12

    Casting Advice

    I am trying to cast a "shuriken" out of aluminum and am having some issues with creating the sand mold.

    Here is the pattern I am trying to copy:
    Shuriken 01.jpg

    I made a print out of the picture and pasted it to a small piece of wood. The wood is about 1/4 inch thick. I then used a band saw to cut the pattern into the wood. The shuriken is about the size of the palm of my hand. I didn't try to make the sharp edges on the template (well I did, but the edges kept breaking at odd places ruining the template). And even if I did, I figured that would make the mold even harder to create. Once the shuriken is made, I can always use a sharpening stone, metal grinder, or Dremel on it.

    The arrow shows the area I am having trouble with the mold.

    Shuriken 02.png

    The sand in these cut outs stick to the template instead of staying in the mold. I put a good amount of parting powder in the cut outs, but that didn't help.

    Anyone have any suggestions how to fix this. I was thinking the wood itself was the issue, so I am thinking of trying to tightly encase the shuriken template in plastic wrap, or maybe a thin coat of polyurethane. I also thought about not worrying about the cut out and machining them out, but that seemed like a lot of extra work and I am not sure I have the necessary tools - other than my Dremel.

  2. #2
    Might be easier to mold to the tangents of the angle and drill the holes later.

  3. #3
    Senior Member
    Join Date
    Apr 2011
    Location
    Choctaw, Oklahoma
    Posts
    1,518
    be a lot easier to just cut them out of steel, by first drilling holes then using a angle grinder with a cut off wheel on it.

  4. #4
    Moderator DavidF's Avatar
    Join Date
    Jan 2012
    Location
    Wilmington DE
    Posts
    2,450
    Re work the pattern so it has the proper draft on it. Then primer/sand/paint the patrern so it is smooth.
    A calm sea does not make a skilled sailor....

  5. #5
    Junior Member
    Join Date
    Mar 2017
    Location
    South Central Texas
    Posts
    12

    Unhappy

    Thanks everyone. Looks like it is the hard way indeed.

  6. #6
    Junior Member
    Join Date
    Mar 2017
    Location
    South Central Texas
    Posts
    12
    At HWooldridge: This sounds like a good idea, I will try this, but I think I will need to get access to a drill press.

  7. #7
    If you have any intent on using them cast aluminum is a poor choice. Use around 12 or 14 gauge steel drill the holes first then cut them out sharpen and heat treat the tips.

  8. #8
    Junior Member
    Join Date
    Mar 2017
    Location
    South Central Texas
    Posts
    12
    Quote Originally Posted by JJJ View Post
    If you have any intent on using them cast aluminum is a poor choice. Use around 12 or 14 gauge steel drill the holes first then cut them out sharpen and heat treat the tips.
    While I would love to get my Ninja on, it is more for show than for anything else. A cool paperweight?

  9. #9
    Senior Member
    Join Date
    Jan 2012
    Location
    Buffalo, NY
    Posts
    2,503
    Quote Originally Posted by Mrasche View Post
    While I would love to get my Ninja on, it is more for show than for anything else. A cool paperweight?
    Letter opener. Wear gloves!

  10. #10
    Quote Originally Posted by JJJ View Post
    If you have any intent on using them cast aluminum is a poor choice. Use around 12 or 14 gauge steel drill the holes first then cut them out sharpen and heat treat the tips.

    I did something similar.
    I used a metal electrical box blanking plate.
    I drilled out the holes first, then used aviation shears to cut the points. I had to lean on the shears pretty heavily because the plate was about 16 gauge, but it's only mild steel so it worked ok.

    Then I sharpened the 'blades' somewhat with a file to thin out the tips a little.
    They don't actually need to be sharp like a knife, just pointy enough to stick in wood.

    Heat treating the tips won't work with mild steel of course, but that's actually a good thing. If they are hard they will snap.
    Being unhardened, they will bend instead of breaking and can simply be bent back into shape.
    I stripped off the zinc plating with muriatic (hydrochloric) acid and heat blued them on the stove.

    The best part is that the electrical blanking plates are only like $0.50 each.
    You can get them with or without a knockout hole in the middle. I thought the ones with the hole looked cooler, but they didn't seem to work as well, probably because of the reduced mass.

    They are very quick to make. In fact, I'd make one now to show you, but unfortunately I now live in NY and it would be illegal

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •