I guess the muller is important, but so is sand type (olivine) mesh 100, binder (So Bentonite 5% + W Bentonite 3%) and 4% water in the formula in the US Naval Foundry Manual. Crumbly sand no good... For iron add 5% sea coal.
Billy, that image provides some clues. Rhinokote LP-600. It is made by Birmingham Hot Metal Coatings. It is listed as a ladle coating. It might be of interest to a nearby commercial foundry. I’d love to get my hands on some. “Ladle Coatings HMC produces magnesium oxide and carbon-based ladle and core coatings. Our coatings promote ease of cleaning and extend the life of ladle refractories. Rhinokote LP-600 and BRS-50 are excellent ladle coatings which greatly reduces the clean out time for a ladle and it can be easily applied by either spraying or brushing and has excellent suspension.” Denis
There is 3000# of it in front of my face and I cant get my hands on it. Bet I figure out a way to get some out of their little bucket one day.LOL
And until then, we might try to reverse-engineer the stuff, perhaps? It needs to stand up to iron, it needs to cope well with thermal shock (grog, or its equivalent), and it's dark gray/black in color. Graphite is probably involved, and I'll bet zirconium oxide /silicon carbide is as well. It's probably got a phosphate bond. Sound plausible?
It does.... but it sounds easier to find somebody to get me some though. When our melt guy comes back after the first of the year he can tell me a lot more about the stuff and what else we have used.
Not sure....here is the contact page for them if anyone is interested in contacting them. https://www.hotmetalcoatings.com/contact-us/
Billy, I used a brand new Super Salamander yesterday to cast 60 pounds of iron. I noticed when I was done that the slag left in the crucible peeled out and the outside was still pristine. I also noticed the crucible came with a brushed-on final coat of black material. Could this be the Black Ice or equivalent? Really makes me suspicious and all the more determined to try to find some. I called HMC today, but closed on Christmas Eve. My suspicion is that coating burns off after a couple melts and then the crucible starts to more rapidly deteriorate. If it could be recoated after each use it might last a lot longer. I am also worried that HMC will be completely uninterested in selling less than 3500 pounds at a time. Anyway, this is a clue we have to investigate. Denis
Bingo. My sentiments exactly. It seems that our needs may well require attempts to reverse-engineer a workable(?) substitute.
Typically companies like making big profits on smaller batches...just need to call and see. I noticed my new crucible was coated as well but it does not seem very thick.