[Sca-cooks] Charcoal forge suggestion ;-)

[marilyn traber 011221]

> I made a forge at my Dad's, when he had his shop. out of clay I 
> found on premises and an old duck egg tuerere(sp)  and some angle 
> iron I welded together.
> 
> I built a wood fire and shoveled the coals into the forge (which I 
> think I had lined with wet large leaves to keep the coals from 
> biting the walls) to harden the surface, and let that go for a few 
> hours, then let it cool.Then I built a soft coal fire, and used the 
> bellows towards the end, then let it cool, then a coal/coke fire and 
> let it cool.   At least that is what I remembered doing, it was over 
> 10 years a go that I did it ( I think 14 maybe).
> 
> My Dad disassembled it when he closed the shop, he had used it 
> regularly over the years as a barbque when he lived in the attached 
> apartment.  He would turn on the blower for that "steakhouse 
> salamander" effect. He said the clay was fired through 
> completely.and had to use a sledge to get the tuere

Yep. You not only were lucky with the clay you used, but you then used the 
proper techniques to fire it thoroughly. Firing clay, on the face of it, 
isn't terribly difficult- you take clay, and you add heat, rather like 
cooking food isn't vary difficult- you take foodstuffs, and add heat;-) It's 
the details, though, that make the difference between a lopsided cup that 
will maybe hold some liquid, and the ceramic nose cone of a space re-entry 
vehicle, just as the details will make the difference between a pot of half-
burned, half raw stew materials in liquid, and, say, a properly prepared coq 
au vin.
 
> > The thing you need to keep in mind that if you'll be using charcoal for 
your
> > fire, you want a fire that's deeper than you'd have for a coal fire. Part 
of
> > what you're doing is focussing the fire with the blower and the shape of 
the
> > fire pot, rather like what you're doing with a glass lens when you focus 
the
> > sun's rays to catch a bit of paper or wood on fire- you can get forging
> > temperatures by burning your house down too, but that much fire is a bit
> > difficult to get close enough to use, never mind being a bit inconvenient,
> > when you try to go to bed that night ;-)
> 
> For charcoal, wouldn't he need a more conical shape?  That would 
> give him a deep, smaller, and concentrated fire.  It depends really 
> on the size of his project.
> 
> I think you could arrange firebricks that way (with some cutting), 
> or clay.
> 
> Cadoc

Actually, I prefer a more cylindrical shape to my fire pot, the reason being 
that the fire itself acts as insulation against the high temperatures you get 
in the heart of the fire. Keep in mind, that the heart of the fire is often 
around 2500 or more, in order to bring the metal up to the approximately 1750 
or so that you use for a working heat. When you're welding, you're moving the 
steel up to roughly 2250 or more, and you need enough excess heat to heat the 
metal quickly- otherwise you're going to take a longer time to bring it up to 
heat, and metals do strange things when they stay hot for long periods of 
times. Even if you have the metal properly fluxed, if you're trying to bring 
two different grades of steel together for pattern welding, the carbon in the 
high carbon piece will wander over into the lower carbon piece, and rather 
than having the two steels you want for pattern welding, you'll wind up with 
one moderately carboned piece- the words "entropy" and "osmosis" fit in here.

And, an upside down cone simply helps the charcoal, etc funnel down into the 
grate. Better to have a mostly flat base to your fire, so the structure is 
more stable.

Saint Phlip,
CoD

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