Richard Gralnik on thu 8 jan 98
Hello and Happy New Year. I've been out of touch with clayart since
the end of October last year, so I thought I'd bring everyone up to
date on the progress of my kiln (The Never Ending Story).
This is not a tale for the faint hearted. Don't read it late at night
if you're alone and planning to build your own kiln. It's a saga
potters will tell their children some day to teach them a lesson when
the kids say "I'd rather do it myself!"
I finished painting all the frame components. My garage still looks
like a make-shift spray booth, with plastic sheeting hanging everywhere
and the floor a combination of primer rust color, engine enamel
red and silver. Wasn't that fun!!! Wearing a Darth Vader respirator
and using a friend's compressor and paint sprayer to coat everything
with a rust-converting hi-temperature (800 DegF) primer. Then
painting it all again with Plasti-Kote 500 DegF Universal Red Engine
Enamel (which I noticed too late contains lead. Not the other colors.
Just the red. I didn't think any paint contained lead anymore but
that color does. Fun cleaning that up.) 20 spray cans worth. Plus,
I found out that there are some incompatibilities between the primer
and the overcoat paint above 400 DegF (a test piece in the oven) and
I would have been better off wire-wheeling off the rust and just
painting everything without primer. Oh well.
Then I had to take the sheet metal skin off the venting hood because
the tube steel frame rusted from sitting outside while I painted
the kiln frame. I DID wire wheel that clean before painting it
shiny silver. I'm still putting the skin back on, but I added an
inside layer of sheet metal to sandwich some K-FAC 1900 1" insulating
board in the walls of the vent directly above the kiln chimney. I'm
also putting wire mesh around the actual opening of the venting hood
so no little critters can fly or crawl in and get toasted.
Next the frame was moved onto the kiln slab thanks to help from a few
friends and some lengths of 3" steel pipe I salvaged from a construction
site and had cut to lengths. They made great rollers for moving the
frame around the house to its new home. I'm happy to report that
everything bolted together tight and square, and the door swings
nicely on its hinges.
I dug a 40 foot long, 1 foot deep trench for the gas line and got
the 1.5" pipe laid with help from a professional plumber. I hurt
for 3 days from all that digging. Now I know I'm out of shape.
I put a skin of sheet metal inside the kiln frame because it turns out
the K-FAC 1900 insulating board loses its mechanical strength when
the binder fires out so that the insulation needs to be protected.
Luckily I know someone who owns an air conditioning duct manufacturing
plant and he let me use his shop to cut the 26 gauge galvanized sheet
metal pieces I needed. I spent an entire day attaching the sheet metal
to the frame with a drill and self-threading screws. It's amazing how
easily the heads shear off those little suckers.
Let's see. Then I bricked up the floor and found that my perfect,
carefully measured, cut and welded frame dimensions didn't allow for
the 1 or 2 pieces of 1/8" thick lytherm insulating paper I used per
course for expansion joint filler. I ended up cutting a lot of bricks
that otherwise would have laid in quite nicely.
I had the same problem with the wall bricks since I calculated my
inside dimensions by brick length with no allowance for expansion
joint space. In the long run it will be better because the expansion
joints should keep the bricks from cracking when they expand under
heat. I'm very good at cutting bricks now, and I found a use for a
couple pieces of left over 2 1/2" angle iron. Bolted to back-to-back
4 1/2" apart on a board they make a great holder for the bricks while
you cut them. Sigh.
Next came the flue and damper section. Thanks to Nils Lou for the
excellent information on how to lay the bricks for this in "The Art
of Firing". My flue opening is 7x5 instead of 7x4 1/2 because my
bricks are laid in stretcher courses, but I have my double venturi
and the space for the damper.
That brings me up to my departure to South Africa for 3 weeks on
business. Before I left I covered the kiln with a big tarp and tied
it down. Unfortunately, I didn't cover it quite well enough, and I
came home to find a 1 foot deep pool of El Nino rainwater sagging the
top of the tarp dangerously deep into the unsupported top of the kiln
frame. Amazingly enough, the tarp held, so a major disaster was
avoided. However, with all the rain that hit L.A. in early November,
moisture had condensed inside the kiln and got the K-FAC damp. I
had to unbrick the entire kiln floor, flue box and first 3 courses
of the wall and removed the wet K-FAC.
Now, there was a problem with the self-threading screws I used to
attach the sheet metal to the kiln frame. The frame is 3/16" thick
angle iron, but the shortest self-tapping screws I could find were
1/2" long. This meant I had a lot of sharp screw ends poking out
of my previously pristine bright red kiln frame like some kind of
medieval torture device. (The screw head was inside the frame
holding the sheet metal in place.) I dreaded grinding them all down
and messing up my beautiful paint job. With the frame brick-less
once again I got a brilliant idea and put it into effect immediately:
Rivets!!
I got a bag of 3/16" diameter, 1/4-3/8" grip range stainless steel
rivets and a couple of cobalt #20 drill bits and set to work backing
out the screws, drilling out the holes and popping in the rivets. A
great way to build hand strength, advance any wrist problems you may
have and occasionally jam your fingers when that rivet POPs!! Ouch.
I also spent a day putting a big tarp over the frame of what will be
the kiln shed to keep the rain out altogether. Many tie-downs, and
rain storms later, I think I've got it pretty secure. It's a little
frightening to go into a tarp-roofed shed after a day when 4" of
rain fell, look up and see the tarp billowing DOWN like sails on a
clipper ship and realize that the sails are puffed by gallons of water
instead of a steady breeze. A series of 2x4 cross supports now hold
the tarp up so the rain runs off instead of filling between the rafters
like sections of a waterbed.
That brings me to late December and another milestone. I turned 40.
Yep. The big 4.0. Some of you may laugh and others may recoil in
terror at the thought, but I had a great birthday. I took off from
work and spent the day bricking up my kiln. I got the floor re-laid,
the flue box and chimney rebuilt, and the first 8 courses of the walls
in. Then we had a family dinner and my kids gave me the cards they
made themselves. Then, my Jewish birthday (7 Teves) came the following
Monday. We had another little party and basically I got spoiled a
second time. Not a bad way to celebrate.
I redid the bricks once more because I realized I'd used some reject
second hand bricks for the chimney instead of the good second hand ones,
but that gave me a chance to fix a couple of minor masonry problems in
the flue opening (Thanks for the good advice Nils!). I also took out
the A.P. Green Greenlite 26's that I'd used to surround the flue and
replaced them with Thermal k-26s. Thanks to Mel Jacobson's post
about the dimension accuracy problems with this line of bricks I
realized that my bricklaying wasn't the problem. The bricks themselves
were too big. I measured to be sure. Yep. 9x4-9/16 (or so)x2-9/16.
Just outsized enough to mess up the tightness of everything around
them. The Thermal bricks are the right size and now everything lines
up, lays flat and looks good.
Finally, I'm very pleased and proud to announce that my kiln frame,
venting hood, burner manifold and supply shelf won a Merit Award
from the Lincoln Arc Welding Foundation in the 1997 Undergraduate
competition.
And the story continues...
So that's where I've been hiding lately. It's good to be back.
Richard
pedresel@3-cities.com on sun 11 jan 98
Richard Gralnik spun quite the tale of his kiln building. The only thing I
can say aside from "good job!" is that a cordless drill with a clutch is the
only way to go when using self tapping screws -- especially the ones with
gaskets used to attach metal skin to buildings. Once you get the clutch set
right you won't shear the head off.
-- Evan back from a holiday in LA where sheer perserverance got him into the
new Getty Museum and sheer good luck won him tickets to the Rose Bowl. A
nice balanced vacation.
At 11:42 AM 1-8-98 EST, you wrote:
>----------------------------Original message----------------------------
>I put a skin of sheet metal inside the kiln frame because it turns out
>the K-FAC 1900 insulating board loses its mechanical strength when
>the binder fires out so that the insulation needs to be protected.
>Luckily I know someone who owns an air conditioning duct manufacturing
>plant and he let me use his shop to cut the 26 gauge galvanized sheet
>metal pieces I needed. I spent an entire day attaching the sheet metal
>to the frame with a drill and self-threading screws. It's amazing how
>easily the heads shear off those little suckers.
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