[TheForge] Ceramic chip forge

[Bruce Freeman]

I contend that a properly constructed aspirated-air burner would work as
well as an blown-air burner.

Blown air is used with natural gas from the mains because that gas is
only available at low pressure. 

( Even so, I expect that a properly constructed aspirated-air burner
could be made to run from it, but that may be more than garage-shop
technology. Anyone interested in doing this would do well to review
Frosty's contributions from the archives.  I expect a simple orifice
wouldn't do, and a needle would be needed as the orifice.  Likewise I
expect that rough pipe fittings wouldn't do, and a true venturi would
have to be build or scavenged - perhaps from a furnace.  These are
untested speculations.)

Bruce
NJ


>>> rich at maynard.org.uk 9/12/2004 3:49:19 PM >>>
I use a ceramic chip forge at the school where I teach. It runs on
natural
gas from the mains, and does use a blower to get the flame hot enough.

At first, you get blue flames burning out through the chips but as they
heat
up (15-20 mins) the chips are glowing and the gas gets burnt deep
inside the
forge.

I think the reason the school bought it - it was before I started - was
the
cleanliness. The school's in the middle of London, and burning coke
here's
not an option!

If anyone wants a little bag of chips to play with I might swap some
for a
railroad spike or two...

Cheers,

Rich.


London, UK.

> -----Original Message-----
> From: theforge-bounces at mailman.qth.net 
> [mailto:theforge-bounces at mailman.qth.net]On Behalf Of Jerry Frost
> Sent: 12 September 2004 18:19
> To: Sponsored by ABANA
> Subject: [TheForge] Ceramic chip forge
>
>
>
> ----- Original Message -----
> From: "GHS" <ghs at execpc.com>
>
> > The reason I said density and not refractory quality is this.
> >
> > In our propane or NG forges the flame is inside the kaowool or
whatever
> > along with the work. The object being to insulate and to heat the
inside
> > surface to the  glowing point  so that it radiates heat back into
the
> > cavity and thus to the work.
> >
>
> Yes, a reverberatory furnace to be technical.
>
> > In a system in which the flame is in effect on the "outside", the
area
> > where the work is not, the object would be to heat the ceramic to
the
> > glowing point so that conduction and radiation would heat the
work.
> >
>
> Evidently the fire is burning in the bed of chips, not outside it.
Other
> than that the principle is the same; heat the chips and the chips
heat the
> work.
>
> > More or less the difference twixt an oven and a frying pan.
> >
> > I have never set lava rocks to glowing as they dissipate heat
pretty
> > much  as it absorbs it. A higher density ceramic should store some
of
> > that energy as it gets to glowing. (less surface area as it relates
to
> mass)
> > The stored energy work be released at the point where the cooler
metal
> > contacted it.
> >
> > A glowing bed of anything should work as a forge.
> >
> >
> > Am a missing a big part somewhere? Could be I am still on the first
cup
> > of coffee.
> >
> > Mike Graf
> >
> >
>
> No I think you're as on track as I am so far.
>
> My contention against lava for media is simply it's low melting point
and
> high silica content. Pumice is silicious to the point that if it
> hadn't been
> full of disolved gasses when it cooled it'd be obsidian (volcanic
glass).
> Using it would essentially be trying to heat steel with clinker.
Basaltic
> lava is only slightly less silicious generally having a higher iron %
in
> part why it's much more fluid when molten and why it has a lower
melting
> point.
>
> I've had lava rocks (vasicular basalt) fuse together in particularly
> fearsome campfires. It wouldn't stand a chance in my forge though
> I may have
> to fire it up and confirm it if pressed. <grin>
>
> Melting temp aside I agree, the lower the specific heat the
> better for forge
> media. Specific heat and density aren't the same thing. However the
> distinction can be meaningless to a working device.
>
> Frosty
> ------------------------
> If it ain't forged
> it ain't real.
> Wrought iron is.
> The FrostWorks
>
> Meadow Lakes, AK.
>
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