I’ve been working on a pattern for a headstock casting. I tried to ram up a mould a few days ago and it didn’t fare so well. I attempted to modify the pattern, this morning, to add a bit more draft - the slight inclination to the surface to facilitate withdrawal of the pattern from the mould, but that, too failed. I persevered with the pattern as it was originally constructed from marine-grade plywood.
The pattern required a lot of metal. More than I am comfortable working with by myself. The thing about hot metal is that it weighs a lot more than cold metal. (Not really - it’s just that you can’t put it down and if it’s weighty, then you don’t really want to be changing your mind mid pour or mid heat). And if things go wrong, the consequences can - and usually are disastrous for the person on the other end of the crucible.
I used a stainless pot, once again, for a crucible and have just about concluded that I want a proper crucible, and tools, because I’m going to end up hurting myself, or worse, others. The pot I was using, today, had some 10kg of metal and it cracked while I was trying to lift it from the furnace. Not good! In spite of that, I had a bit if a mess but a reasonably successful casting. (See attached pics). I won’t try to re-do it because it’s a lot of effort and risk for a result that might not be any better than the current casting.