"Andy Dingley" wrote in message
...
On 28 July, 01:46, The Natural Philosopher
wrote:

oil is the prefered way to get the carbon.

No, oil is one of the least effective (short of pure carbon) ways to
get the carbon.

You can't case-harden or carburize with carbon, because carbon's a
solid up to some enormous temperature and so it won't move from the
bath to the metal. As for pretty much any steelmaking process, the
elemental carbon is transported around as the conveniently portable
and reactive gas, carbon monoxide. There are also industrial liquid
processes using cyanides, as these are denser than gases and more
controllable.

You make carbon monoxide in bulk from coke, or more conveniently for
case hardening from carbon dioxide and an activator (usually barium
salts) that strips some oxygen from this to make the monoxide. As is
well-known, "hoof and horn" (or Kasenit) is the usual supplier of
this. However as oil is a hydrocarbon, it won't do this - at case-
hardening temperatures, bulk oil in the absence of oxygen is pretty
stable. That's why it's used as a quench (deliberately non-reactive),
but not for case hardening.


Trust me: sugar does the job well. In the days before cheap Chinese masonry
drills, I used iron water pipe to make holes in brick walls, by dunking in
sugar at red heat after cutting a few rough teeth in the end. This was a
dodge shown to me by someone's dad who was no doubt also shown it by someone
else's dad before him... I still have a pot in the garage: and it's
beginning to get a bit mucky.

But we're getting OT

S