[TheForge] photos under "inexpensive recuperative forge"

[Michael]

Frosty,
The problem with shooting you a sketch is that I'm presently torn between
greed and elegance. That is to say elegance in the engineering sense
(simplicity). What the dilemma boils down to is that some part of me--the
greedy part--wants to build an impossibly large rectangular ceramic chip
brazing hearth; it's kind of a bragging rights thing :-)

The sensible part knows very well that a much smaller circular design is far
more practical--meaning it's the version 99.99% of metal smiths would use
and be happy living with; you know, the "what's this beast doing eating my
garage" factor. The dilemma is caused by the fact that both Jeckle and Hide
design side by side within Dr. F's brain; the infighting has been ferocious.

Sanity is slowly gaining the upper hand, and the circular firepot made with
a mullite sagger, placed outside of a high-heat castable (4000 F +)
refractory inner wall is slowly emerging (of course the sagger could be used
for the inner wall and considered an easily replaced consumable for portable
versions). Naturally this design would allow the continued use of Mikey
burners, for the intense heat swirling in the fire chamber below would have
room to dissipate into the  chamber's greater area before encountering the
supporting grill and ceramic media above it (or the crucible when the media
and grill are replaced for casting mode >:-) This design should also prove
very satisfactory with your own exhaust gas recirculation preferences. Of
course, all of this brings up more than a little guilt over the idea's not
sufficiently emerging last year, possibly preventing the melting of the
other Michael's grill and ceramic media...

The bats in the belfry are quite disturbed at castle Frankenburner lately
(OK, more disturbed than usual). By the way, the circular fire chamber would
also allow heated gases to be drawn into the fire chamber through a hole
placed next to the burner, which would allow the burner nozzle to be made of
refractory--for the hole could be subject to a movable choke--permitting the
burner's position to be unmoving. With variable chokes into and out of the
plenum chamber, optimum performance would only be a question of tuning. Best
of all, their tuning can be completely separated from that of the burner.
Such a chamber can also successfully employ low cost safety devices, for
they can enter far enough from the flame not to be adversely affected by its
too-high velocity, but still close enough to re-ignite it efficiently (not
that I believe in this kind of safety; constant vigilance is the preferred
safety device in my view).

There are still "problems" to be ironed out, not least of which is that a
ceramic burner flings the door wide open to convenient multiple fuel use,
thus working the oil-burner fans into a lather all over again (sigh). I
suppose it was inevitable...

Before you multiple fuel burner fans even ask:

Method One:
Use an SS capillary tube from smallparts.com (they even have the perfect SS
fitting available for sixteen bucks). Beside the SS capillary tube, run the
tube for oil injection. Thus we find that retrofitting tube burners of
various types (even old Aussi burners) for multiple fuel use hardly
constitutes a challenge.

Method Two:
Employ lathe turned end caps (locked into the burner's end with a
thumbscrew) for quick change between fuel gas accelerators and oil
injectors.

Worst of all: This design can be rotated between vertical and horizontal,
making it the natural successor to the Multi-hole forge/furnace. Dang; I
guess it's time to get off my butt and go back to building. 
Mikey