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Thread: New Plaque Pattern

  1. #1
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    New Plaque Pattern

    I needed to replace the pattern that I used for various plaques.
    The old one was copied from the Navy Foundry Manual and is pretty well shot now. I've repaired the ingates a couple times and the toll from removing letters and numbers has left a rough surface on the face. I got about 15 plaques out of it.

    http://www.alloyavenue.com/vb/attach...9&d=1421013310

    I decided to make the new one from 1/4" Lexan that I had laying around and use a full length knife gate. This should give me a good base that will release the alphanumerics when using contact cement. It should also be easy to de-spue on the table saw.
    The overall size is 8 x 10 and the finished plaque will be 5 x 10. I left a 1/2" trash gate on the far side in case of sand wash and a place to put a vent.
    The edges were cut at 10 degrees for draft and used 1/4" auto trim molding for the outline. I like using that as it has good glue on it and is easy to apply. Super glue with PoP sprinkled on it for the radii.

    IMG_2523.jpg

    The sprue well / runner has a choke right after the well to trap sand and hopefully air.
    I added a super glue/Pop radius on the bottom of the pattern by using painters tape on the runner and coating it with grease as a release agent, put it in place and then a couple applications of the glue/PoP to build the radius. This gives a secondary packing of the sand at the junction of the ingate.
    I gave it a test mould and only had to cleanup one edge where the trim mold pulled the sand.

    IMG_2524.jpg

    Hope to put it to use this week.
    Last edited by FishbonzWVa; 10-18-2016 at 10:22 AM.
    Bones

  2. #2
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    I'm not sure why but it says your link is invalid.
    It sounds like you got pretty good service from your last pattern. I've found Lexan to be pretty good with adhesive solvents. Heat and sharp objects notsomuch. Alcohol, kerosene and Goo Gone are the go-to adhesive solvents in my sign shop.
    It certainly won't break though! Maybe flex a bit or get scuffed after awhile but I bet it'll work great.
    I have a few gating patterns that I use for just about everything. It saves an awful lot of time and avoids a lot of loose sand from digging the gates and well.

    Pete

  3. #3
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    Tried a copy/paste on that link to fix it.
    I think the overall re-design will be much stronger than the old one, those ingates were just glued to the MDF, making them fragile.
    I try to incorporate the sprue well /runner/gates when ever possible, just so much easier to mould.
    Bones

  4. #4
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    I found the actual thread and re-read it. I took the liberty of copying it here. http://www.alloyavenue.com/vb/showth...-Plate-Casting
    It's one of the more instructive ones I've read in awhile.

    Pete

  5. #5
    I am in the middle of a plaque project, so I made a quick one hit pattern so as to cast a permanent Aluminium pattern. As I will be making derivatives of the first I will also be using the Aluminium copy to make other patterns
    The only time You're not following your nose is when your going backward!.......Andy (ME) .
    Have you filed in "Who do you think you are?" "War Grade Report" " My photo's"

  6. #6
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    Well crap, I should have re-read that post or checked my other pattern, got it upside down again.
    I'll do a test pour first and if I get inclusions, I'll flip it over and mount it permanently to the runner.
    Bones

  7. #7
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    Got to test it out today.
    The runner caught the inclusions, nothing on the main body or the trash gate.
    A couple things in the photo, the blue arrow points to a line I lightly scratched on the pattern to align the numbers, hard to believe it transferred.
    The red circles are areas that are rough, looks like ice crystals, frost. Can someone diagnose this? I'm at a loss on the cause.

    IMG_2528.jpg

    This is the rest of what was cast.
    Skulls and a sand ram in lost foam

    IMG_2526.jpg
    Bones

  8. #8
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    Made another pattern for house numbers.
    I left three tabs on the arched side to use for venting and a full length knife gate for feeding.
    I really like the Lexan, makes swapping out numbers painless. I used a tiny drop of super glue on the top and bottom of the numbers and a razor blade popped them right off.

    IMG_2547-crop.jpg

    Cast these yesterday

    IMG_2548.jpg

    Cleanup and powder coating today (it's really a blue background).

    IMG_2549.JPG

    Three Xmas presents knocked out.
    Bones

  9. #9
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    Those came out very nice. But you got my house number wrong.
    A calm sea does not make a skilled sailor....

  10. #10
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    Thanks David. LoL
    Compared to most of the other stuff I cast, these are a piece of cake to finish up. Spoils me.
    Bones

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