Thanks once again to all who gave suggestions as to why the
explosion occurred in my ingot mould.
I am now completely convinced that it was ambient moisture that
caused the problem. I only use propane gas and the ingot mould is
coated with soot from a candle.
I finally bucked up the courage to remelt some scraps and spent much
longer than usual heating the mould. As I first heated it I noticed
a moisture line receding down the side. For some reason or other the
thing attracts moisture … and yet not enough to cause rust. We
live and learn.
Thank you,
Renate
I finally bucked up the courage to remelt some scraps and spent
much longer than usual heating the mould. As I first heated it I
noticed a moisture line receding down the side. For some reason or
other the thing attracts moisture ... and yet not enough to cause
rust. We live and learn.
It isn’t so much that it actually attracts moisture, you’ve just got
it cool enough that given an environment very rich in excess
moisture, it condenses on the mold until the mold is too hot for that
condensation to happen. Kinda like the windows in your bathroom
when you take a hot shower with no fan on. You’re wondering what
this moisture rich environment is? It’s your torch flame. One of the
principal combustion products of hydrocarbon fuels is water vapor
(the other is carbon dioxide). When the torch flame hits the cold
metal, the water vapor outside of the hot zone of the flame,
condenses and leaves water on the mold. It won’t rust because it’s
only there for a short time before it gets evaporated off again once
you’ve got the mold hot enough.
Peter
I finally bucked up the courage to remelt some scraps and spent
much longer than usual heating the mould. As I first heated it I
noticed a moisture line receding down the side. For some reason or
other the thing attracts moisture ... and yet not enough to cause
rust. We live and learn.
Sounds as though you have some condensation occurring. All
combustion produces, amongst other things, water vapour. This will
condense on or in your mould if it is cold. Hope you manage to cure
the problem without any further “excitement”.
Kevin (NW England, UK)
Hi, The "moisture you see is condensed out of your flame . “All” fuel
gases have watervapor as a byproduct of combustion , untill you warm
your ingot mold [or other metal surface , haven’t you seen water on
your metal projects as you first heat them up?] enough , the metal
is cool enough to condense the water vapor . Thus the cause of the
moisture and why it doesn’t rust .
Mark Clodius