On the first cast attempt everything seemed to go wrong but the resulting casting was useable with a some milling for cleanup. But I do not have a working mill. Although the center pocket has sufficient draft it was fragile. The worst was a breakout in the upper right corner of the pocket. And for some reason the left edge of the rectangle came out tapered. Not sure how that happened.
So on the second attempt I may add some mails to hold it into the sand below it. Actually sheet rock screws. This pour let me know how much aluminum was needed and that there are no noticeable shrinkage issues. This is most likely because the hollowed out back side reduces the volume.
This time I am going to attempt to feed the mold cavity from the left side so I can cut most of the gating with the band saw.
Rammed up the 2nd but never poured it. Even with the screws the center section fell apart. Three choices here. The 1st is to use the other sand for the center and faceing sand. The 2nd is to make a core. The 3rd is to just live with the casting I already have. Its not show piece but it works and I think that is the better choice. I can chase this problem while making the pulley.
Not sure why I messing with this 2nd string sand. I have good stuff but I wonder if adding a bit of bentonite to it will help. Hmmm
Not sure why I messing with this 2nd string sand. I have good stuff but I wonder if adding a bit of bentonite to it will help. Hmmm
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