I found some Youtube videos on this how to make it.These show usually a guy putting bearing balls in a standard clay / graphite crucible. Then they put some graphite powder on it, some flux and some glass shards as extra flux. What amazed me that they don't pour it out, but let it freeze in the crucible and sometimes even seal the crucible before melting. After opening the cooled crucible they succeed to release the frozen steel bum without damaging the crucible. Why don't they just pour it into a blank for e.g. a knife ? Forging a bum shaped piece of steel is much more work than a knife blank. I want to try it myself.