Don, Michael and others,
As far as preventing molten metal from sticking to a steel ingot
mold, there are a few different ways to do it, and probably more.
Sooting it with an air-starved acetylene flame does a good job, but a
very light coating of any kind of oil works nicely, too.
If a coating of oil is used, make sure that it is wiped almost
completely out of the ingot mold’s interior, however. Only the
thinnest amount of oil is required to prevent sticking of the ingot.
It is vital that some air be able to escape from the two halves of
the metal mold when the liquid metal is poured into it, and an excess
of oil can hinder that air flow. Too much oil can not only keep the
ingot mold from filling completely, but may actually cause a "burp"
when the ingot is poured. Hot metal contacting oil can force the
metal back out of the ingot mold, sometimes quite forcefully…not a
I think of ingot molds like a seasoned iron skillet. After continued
use, the ingot mold just seems to resist metal sticking to it. When
ingots eventually become difficult to remove from the mold, then I
will either soot or oil very lightly oil my ingot molds. Most of my
poured ingots pop loose from the mold with just a light tap on the
top of the ingot with the mold clamp. Be sure to warm the ingot mold
with a torch flame before pouring hot metal into it, as cold steel
at room temperature has a certain amount of atmospheric moisture in
it. Heat will drive off any moisture which can cause a big problem
with steam during the pour. Any possible moisture in an ingot mold is
to be avoided, absolutely.