Arnold Howard on tue 9 nov 04
Here are some Kiln Sitter maintenance ideas that can help prevent an
over-fire. I'm sending this to Clayart because of the Kiln Sitter meltdown
that we discussed recently.
1) Before loading a cone onto the cone supports, check that the actuating
rod can lift up and down freely. If the rod movement feels sluggish,
corrosion may have built up inside the tube. Sometimes you can clean out the
tube using long cotton-tipped applicators. (They look like Q-Tips.) Do not
fire the kiln until the actuating rod moves freely. If necessary, replace
the tube.
2) The cone supports (the metal tabs where the small pyrometric cone is
placed) must be kept clean. Use emery cloth to remove traces of greenware,
corrosion, or bits of melted cones. These foreign materials will catch on
the cone, preventing it from slumping freely. Coat only a small amount of
kiln wash on the lower side of the rod and on the upper edges of the cone
supports. A build-up of kiln wash will alter the cone's shut-off
temperature.
3) If the Kiln Sitter does not shut off when the weight drops, the locking
slide inside the Kiln Sitter may be corroded or dirty. About once a year,
unplug the kiln and remove the switch box that houses the Kiln Sitter. Pull
the box straight out to avoid damaging the Kiln Sitter tube. Leaving wires
attached, clean the backside of the Kiln Sitter. Canned air is helpful. (But
do not blow air into the Kiln Sitter tube.) When you reinstall the switch
box, arrange the wires so they do not interfere with the locking slide that
trips when the weight drops. (You can see how the locking slide works by
lifting the weight, pressing the plunger, and then dropping the weight.)
Also, arrange the wires inside the switch box so that wires do not touch
element connectors or the kiln case.
4) Adjust the Kiln Sitter using the firing gauge. This is a small disk that
ships with new kilns. (Many people throw away the firing gauge thinking that
it is used only during shipping.) Adjust the Kiln Sitter with the firing
gauge every dozen or so firings.
How to Use the Firing Gauge
Place the gauge on the cone supports, sliding the actuating rod through the
hole in the gauge. If the actuating rod is not centered in the porcelain
tube, loosen the two screws on the guide plate and move the guide plate from
side to side.
Lift the Kiln Sitter weight to the raised position. With the firing gauge in
place, the trigger should just barely clear the release claw, coming as
close as possible without touching. If the gap is wrong, loosen the set
screw in the center of the weight, move the trigger and retighten the set
screw.
This adjustment is easier to understand when you see pictures. You can
download the Kiln Sitter instruction manuals at Paragon's website:
http://paragonweb.com/catalog.cfm?type=manuals
Sincerely,
Arnold Howard
Paragon Industries, L.P., Mesquite, Texas USA
arnoldhoward@att.net / www.paragonweb.com
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