Casting Brass For Machining Stock

Discussion in 'Metal casting projects' started by Robert, Sep 5, 2018.

  1. Robert

    Robert Silver Banner Member

    When I said stir, I really meant plunge it. Worked great!
    R
     
  2. Robert

    Robert Silver Banner Member

    I found no porosity or defects during machining!

    [​IMG]

    Robert
     
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  3. crazybillybob

    crazybillybob Silver Banner Member

    ohhh Pretty!!:)
     
  4. Robert

    Robert Silver Banner Member

    I have another metallurgy question that I hope you can answer. I ordered some electrical copper which I suspect will be actually Te Cu, probably in the range of .5% Tellurium. If I use this to make red brass and silicon bronze will this impurity be a problem? My understanding is that Te improves the machinability of the Cu. Has anyone used buss bars or similar material successfully? If no one knows the answer, I will proceed and post my findings to contribute to the data base here!
    Robert
     
  5. Peedee

    Peedee Silver

  6. Robert

    Robert Silver Banner Member

    I had no idea about the absorption of Te. Crazy. Hopefully, it stays in solution and I do not breath any. I will be avoiding the zinc fumes anyway. Peedee- I cannot seem to find where CuTeSi is discussed? Do you have the page number?
    Robert
     
  7. Peedee

    Peedee Silver

    I can't find it either now!
     
  8. You were searching for terillium, is that another name for tellurium?.
     
  9. Peedee

    Peedee Silver

    No, it's a cock up on my part. I first searched the books for Cu Te Si. There are two books in the series and worthy of a read. Tellurium alloys are discussed but the relevance to Robert's application is questionable.
     
  10. I'd watched this video a few weeks ago by chance, these university chemists have covered almost every element in a video:
     
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  11. Robert

    Robert Silver Banner Member

    That guy has bad Parkinsons. Anyway I am making telluriated red brass!
    Robert
     
  12. Robert

    Robert Silver Banner Member

    Got my copper buss bars today. Weighing out alloying material for Telluriated Red Brass:
    [​IMG]

    Those are not pennies. They are copper plated zinc ingots. 97.5% Zn by weight. They tend to fume less after copper plating.

    Robert
     
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  13. Robert

    Robert Silver Banner Member

    Working on a match plate for the next batch of Brass. I probably should have a longer runner but I did not want to go with a larger flask. The part will be gated from the back on the flip side of the match plate.

    [​IMG]

    Robert
     
  14. PatJ

    PatJ Silver Banner Member

    That is a nice matchplate.
    I have toyed with those, but never gotten them to register correctly when using a split pattern where half the pattern is in the cope and half in the drag.

    I tried Adolf's inserts, and that did not work correctly either.
    I think when drilling the plywood, the wood grain causes the bit to drift off a bit, and it does not take much drift to mis-align a small part or parts.
    If I tried a matchplate again, I would use a piece of sheetmetal, or perhaps cast an aluminum plate.

    For patterns contained completely in the cope or drag, it would be much easier since there is no chance for mis-alignment.

    .
     
  15. Yes the matchplate pattern looks great: good quality materials too. I cast something similar to a female Adolf's inserts in epoxy to use up any leftover epoxy resin. Once fitted to the plywood, I then cast the male matching version in situ to get perfect alignment every time. I wax the two mating plywood bases around the holes to prevent the resin from sticking and add some fine brass or aluminium swarf to the resin, which prevents it from getting too hot. Forstner type drills cut a nice sharp hole in plywood.

    Apologies for taking a sidetrack from the main topic.
     
    Last edited: Sep 22, 2018
  16. Al2O3

    Al2O3 Administrator Staff Member Banner Member

    As always, nice work Robert. Unless you have removable flasks and/or plan on making multiple molds for a given heat, there's not much to be gained taking up real estate on the match plate by additional alignment features as long as your flask pins are reasonably accurate. With respect to commercial registration hardware like Adolf's and other taper cones, the tightness of fit can be tuned with installation height. More alignment and registration features demands higher placement accuracy just like adding more bearings to a single shaft. The same tends to be true as mold size increases. You don't need as much registration feature contact area for hard resin bound molds as required in green sand molds.

    One other trick to consider is you really only need one round registration button as long as it has sufficient contact area for the strength or you mold material. The second registration shape can be square or rectangular similar to how many flask alignment pins work, meaning the one circular registration feature constrains alignment in all directions and the other rectangular feature allows clearance along the axis of the flask pins but constrains motion perpendicular to that.

    I too have cast in many registration features with tooling resin but depending upon shape and mold size, I usually use foil or other tape on the master before casting the mating surfaces onto the match plate to build in some clearance between the registration features.

    With that match plate, it looks like more hold down clamps in the making.

    Best,
    Kelly
     
  17. Robert

    Robert Silver Banner Member

    I found out yesterday why it is important to cut gates between the runner and the pattern...duh.
    R
     
  18. DavidF

    DavidF Administrator Staff Member Banner Member

    Ive done that too, and also put the cope on 180' out... So I'm allowed to laugh a little.... :D:D:D
     
  19. Robert

    Robert Silver Banner Member

    I poured again today after my release from the salt mine. I remembered to cut gates. Pics to follow. I'm letting the flasks cool overnight.

    I did create this weird alien ingot of dross and Si Bronze. I find it very artistic. Reminds me of the Japanese mission to Ryugu.
    [​IMG]

    [​IMG]
    Actual mission image...
    Robert
     
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