Delft Clay Casting Help

I am hoping that someone could let me know what is going wrong with my cast?
I have attempted to cast this ring around 5 or 6 times now and I always end up with the same result.

Since I took these pictures I have made the pour hole as large as the widest part of the ring and have tried adding an air vent in the opposite end of the ring, but the result is the same.

This is my first attempt at casting anything using delft clay after watching all of the At The Bench videos.
I am using plenty of borax and I make sure to heat the silver for around 30 seconds after it goes like mercury. I also make sure to keep the heat on the metal as I am pouring it in.

Any advise would be appreciated.

your pour is trapping air in the mold

  1. make an air escape hole, furthest away from the metal entry point, and

  2. orient your ring model so that it is vertical when you cast

best

Thanks for the response Mark, ill try again with a better air escape hole furthest away from the metal entry point.

Would I would need to make a rectangular casting “ring” that can part from top to bottom to cast vertically?

Cheers

For rings like this I use a side entry Delft ring. Adapt a standard one.

And I simplify the vents down to one or two, using 0.8mm wire. With the wire push out a single vent opposite the sprue straight to the outside. Maybe do one each side, both opposite the sprue.

Depending on the metal temp you’ll either get a 0.8mm stick to clean off or a tiny button where the vent was (they can look quite nice if left there).

Brian
Auckland
New Zealand

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