Ive been doing the same for a few months now, just repairing and upgrading alot of my casting stuff, which was in alot worse shape than I remembered it being, lol. As for flasks, I think that's probably the only thing I havnt made any new of or replaced any, even tho I probably should since mine are probably 30% charcoal by weight at this point, lol. Ive made new sand rammers, new sand riddles, new sprue and gating forms, etc. My sand scoop gave out during the first time I tried ramming up some molds, so had to make a new one of those too, lol.
Due to working on the casting shed for the last year, alot of the stuff just got put outside under a tarp and it didnt fare well, especially the wood stuff, and the wiring on the sand muller and such got all chewed up, so it had to completely be rewired and fixed. I had an old analog timer from a microwave, which I wired it up originally but due to some issues, the wiring on it got ripped out of the back of the plugin and I just was forced to direct wire it so you had to plug it in to use the sand muller and set the time on a phone or something.
A few weeks ago, I actually managed to get out and do some castings, which I made up the patterns for a bending iron, for bending wood sides on acoustic guitars and just bending wood in general without needing to steam it, a matchplate vibrator and knee valve from steve chastain's books, oil filter adapter, and a few blocks that will be machined up and turned into air manifold blocks for plumbing compressed air around the new casting shed. I also made up a pneumatic sand rammer too, so need to upgrade all of the compressed air stuff in the shed too, so I can use all of it.
I already machined up the bending iron, which really wasnt much of machining really, just drilling a few holes on the drill press and cleaning it up with a flap wheel on the angle grinder, then pressing the two 200w cartridge heaters in it and make the base for it. The base is made of curly cherry, and the white part is a 3/4" disk of ceramic wool that I recessed into a pocket in the top, and then stabilized it with some watered down sodium silicate to act as a thermal barrier between the bending iron and wood. It's just propped off of the base by some bolts, washers, and nuts to act as standoffs.