Nan Rothwell on mon 24 nov 97
Hi Rafael
You asked about IFB door construction and about applying ITC. I will comment
on your queries in the opposite order.
I am glad you asked the second question, since I am facing a similar quandary
about when to apply ITC in building a new salt kiln. I don't want to put ITC
on top of already-salted bricks or shelves. After talking with Alice at ITC,
I have concluded that I should probably run one or two bisque-temperature
firings in the kiln before applying the ITC. Since I normally raw-glaze,
running bisques will require some unnecessary work and expense. But I am
willing to undertake it in order to get the ITC on as prescribed.
That's an option for me because get my primary heat rise with propane and I
can just skip adding wood and salt. Your case is less clear. I haven't much
experience with wood as a primary fuel (I only use it to add fly-ash and
increase reduction) but in my observation, you'd get far too much rough ash
buildup if you were to take the kiln up to a bisque temperature and stop
there. Are you working in a institutional setting where you could "borrow"
some portable burners form another kiln and get the kiln hot with them? I'll
be curious to hear what others on the list advise and what you decide...
As for the shelves, since you do have the option of firing the Thorley
shelves in a clean environment before putting them in the wood kiln, I think
you would be well advised to do so. (BTW, My friend Kevin Crowe has used
Thorley's in his wood kiln for years and they're doing okay -- lots of ash
build-up, but as long as you wad everything as for a salt firing, things are
fine.)
In answer to your question about door construction, I am forwarding a recent
post from Vince Pitelka on that subject. (Vince has a remarkable ability to
create clear, lucid descriptions in words. He was generous enough to write
me this detailed description of his door construction. I am assuming he
won't mind my sharing it with you and the list...)
From Vince Pitelka:
"After receiving your post I went back and reviewed that post of mine on
hinged kiln doors. I still agree with everything in that post, but I have
another favorite kiln-door design, which we used on our new salt kiln, and
which you may wish to consider. The frame and hinge assemblies are just as
described in that other post, but with a few exceptions. When building the
door frame out of 1/4x4" angle, drill a row of =" holes on 8" centers down
the middle of each side angle, on what will be the edge of the door (rather
than the face). Purchase enough 1/2x1" bolts and nuts for all holes. No
washers are necessary. Stick a bolt through each hole from the inside, with
the nut threaded tightly on the outside. Weld around the base of the nut.
This requires a hot arc and a quick hand, so that the arc does not burn
through the nut into the threads of the bolt. After the welds have cooled,
remove all the bolts. Paint your frame well with rust-proof primer, and
hang it on the hinges. Dry stack a single layer of IFBs, with no fiber
board, staggering the courses, cutting very carefully to leave a 3/8" gap
between the bricks and the frame up either edge of the door. When all
bricks are in place, slip an appropriate length of 1/4x3 flat bar into the
space on either side of the bricks, and thread in the bolts from the
OUTSIDE. Finger tighten them all, on both edges of the door, and then
tighten them a little at the time, from top to bottom on one side, then top
to bottom on the other side, alternating back and forth until the flat bars
are snugged firmly against the bricks. The softbrick door on our previous
salt kiln, which was of exactly this design, required no adjustment or
repair in seven years of VERY HEAVY use. I always assumed that that door
was cemented together, but when we tore down the kiln and cut away the door
frame, all the bricks fell free. I was amazed, and I became an immediate
convert to that type of door. The kind I used to build works great, but
this other design gives the possibility of disassembling and repairing the
door if the need should ever present itself."
Hope this helps,
Nan Rothwell -- in Nelson County, Virginia
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