Ok Scottie, prepare to ram!
Solenoid engine BuildI ran low on sand so I used what I had. I have not poured anything this size and have never used any weight on top of the flask. So with the reduced sand load and no weight holding the flask together - disaster! The metal lifted to half up and started spilling out between the cope and drag! I didn't take any photo's because I was scurrying around and shouting bad things!

Solenoid engine BuildTo top it all off the sand had broken apart in the mould!
The results..
Solenoid engine BuildThe next attempt, after re-mulling the sand with a little more water and clay, I clamped the flask together and stacked on some weight. This had better work!
Solenoid engine BuildOh, when I was pulling the pattern for the second pour, I dropped it!

So it really better work!
Solenoid engine BuildSuccess! Not too shabby looking after shake out, no clean up other than cutting the sprues off.
Solenoid engine BuildComparing the two results. More lessons were learned the hard way on this pour..
Solenoid engine BuildThat's it though with my homemade green sand. It works OK, but you have to be fiddling with it all the time to make it preform well. Life being shorter that it was, I am too creaky, cranky, and lazy to deal with it.
I got online and ordered a pile of Petrobond. Now I have to build a moulding bench..
The saga never ends.