One of Those Nights

Discussion in 'Sand Casting' started by Tops, Nov 1, 2022.

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  1. Billy Elmore

    Billy Elmore Silver

    I think the casting is feeding the thick ingate on the center cavity and that is why it is the only one showing shrink at the top. By moving it to the cope side and moving the sprue closer the sprue will feed the ingate and cavity. If you use a sprue well at the bottom I would make it as little as possible to avoid feeding metal from the sprue and ingate to the well. I would add a 1/4" vent hole in the thick sections if you are concerned about them shrinking. The vent will not only let some heat out and give you better surface finish but will feed the thicker sections if you make the contact point heavy enough.
     
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  2. Melterskelter

    Melterskelter Gold Banner Member

    By the way, nice results on your first match plate.

    I looked for a while at your setup and toyed with adding a riser to the runner next to the gate. But with close proximity of the other two tools, that riser might cause a shrink defect in them mid-shaft as it might delay freezing there. So…, if it did not offend your sensibilities, I’d probably add a riser right on the top of the spot where the tool head collapsed. I think I’d just make the riser have a roughly 5/8” x 3/4” neck extending upward 1/4” to a maybe 1” sphere. It would, in other words, look sort of like a lightbulb. (No reason it could not be an open riser, as well). That would ensure that the final freeze would occur in the area of prior collapse and the bulb would still be liquid after the tool froze.

    Just another take on the problem that might work.

    Oh, and at my shop, if I were tired of casting, I might just fill the defect with tigged aluminum and grind it to contour—-crude but effective.

    Denis
     
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  3. Tops

    Tops Silver

    Thanks Billy, thanks Denis. The cavities are epoxied in (maybe should have just used screws this time around?) but the gating is just hot glued so should be easily removed or altered.
    I don't have TIG welding at home. I could probably try at work sometime, would need coaching as I have yet to try aluminum.
    Speaking of work, one of the machinists did me a favor and thinned/milled the first 'iron' down to .115" (short 3mm) so I can mess with it until my cast iron one is sorted.
    tops_irons_mallet.jpg
     
  4. Tops

    Tops Silver

    I decided to rework the match plate. If I can get it to pour in aluminum I may look for someone to pour it in iron or take it to a community iron pour after checking with the organizers. None of this is really cost or time effective but it is a diversion from the worries of the day job and inside work while it was below freezing outside.

    Drag side: move runners to handle ends to lessen clean-up, lengthened feed runner, added laser-cut cardboard symbols to 2 irons, cleaned up logo on third iron, coated bare materials and joints with epoxy
    Cope side: added 3D printed risers coated with epoxy, moved sprue, ground off lighting bolt (all symbols now in drag)

    Plan is to sand a little, coat it with paint to remove the 'ugly Christmas sweater' color scheme, and give it a go.
    tops_match1_r1.jpg

    tops_match1_r2.jpg
     
  5. Tops

    Tops Silver

    I finished the revision to the match plate, painted, graphited, and cast it. Other than not getting the sand packed around the risers (so that it broke out at pattern extraction pre-pour) I am pretty happy with the result. Not having bumps on the round part of the handles it going to be a boost for clean-up and feel. On the aluminum band saw at work this is about 60 seconds to clean up...
    Next steps are for me to spend some time with the castings after clean-up for size and feel and develop a more organized plate with all 'favorites' and look to get it poured in iron. Thanks for all of the tips, etc. it is really appreciated.

    tops_mp1_rev2a.jpg

    tops_mp1_rev2b.jpg

    tops_mp1_rev2c.jpg
     
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  6. Melterskelter

    Melterskelter Gold Banner Member

    Nice results! It looks like all the risers fed the boss ends of the tools. That is especially true of the one nearest the sprue. I think it is also interesting to see that the one near the sprue collapsed on the hot side—-near the pouring basin and sprue. That is just as it should be “ in theory.” But it is always interesting to get validation of the theory. The blind risers you printed look very good with generous contact with the mold cavity—-a strategy that has worked well for me.

    way to go!

    Denis
     
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  7. Tops

    Tops Silver

    Thanks Denis. I would not have gotten this far without the advice and encouragement to try again from everyone here.
    tops_mp1_rev2d.jpg
     

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