Metal Casting Zone

Well, that may have been too long.

You have to start with good cast iron. I like the thin stuff with at least some machining done on them. The easiest way to anneal it is to pull it from the sand while it's still red hot and put it in your hot furnace, close it up to cool slowly. We had talked about adding FeSi at the stir but I think that just helps fluidity of the pour, I think the extra Silica would make it harder to machine. I wonder if a small amount of lead would help? Just don't breath it.

it just came to me! mind you im not an expert on cast iron but one thing i know is that molten cast iron is hungry for carbon! was your furnace making smoke!! if so this explains a lot! shrinkage and hard machineing. ah the bubbles in the casting! im thinking that at molten time you have too much free carbon!(smoke)available. what do you think???

i think you are doing a great job rob. my only regret is i cant follow suit yet!!!!!!your trials and errors are extremely valuable to me. this is a learning forum and we all learn from others efforts.

sounds good to me. bronze will work just as good as cast iron for your item. the hobby foundry near here cast small anvils in bronze and they come out just fine. sorry to hear about your crucible. maybe crush it as a base for making some new ones or a lid for another crucible.

I cracked my little homemade one when I did iron, I didn't get it back in the furnace fast enough after the pour. Too busy taking pictures and scraping the crud out of it. Made a nice little "PING" sound, I knew I was hit. Oh well, it wasn't supposed to work, even for Aluminum, according to the naysayers..
Sorry, Aluminium.

I don't think Bronze will have the same shrinkage problems as Iron. Should be fine. I used to have a site for thermal expansion equations, same as shrink factor only in reverse. I'll see if I can find it.

Those are good Rob, how did you gate them? What's the Diameter?