Andrew Birkett's nobugs.org
Now I’ve replaced the “cope” on top of the “drag”. You can see the door-locks which I use to keep the two halves aligned.
I cut out a funnel shape at the top of the sprue pin, using the old kitchen knife. Actually, I did this while the two halves were seperate – otherwise the sand would’ve fallen down the sprue pin and blocked the mould.
I’ve extended the funnel out towards the middle of the flask so that I have a bigger area to aim with the molten metal.