Service manual

Ceramics
Overglaze
Breaking in Overglaze Firing can be caused by poorly
fired bisque. A slow bisque fire is always better for ware that is
to be china painted. The greenware should be completely dry
before being placed in the kiln. Standing plates on edge or us
-
ing a plate holder gives good heat circulation and will help in
preventing plate breakage.
Peeling China Paint can be caused by applying the paint
too heavily.
Loss of Color in China Paints is usually a result of
overfiring, or thinning your paint with too much medium when
applying.
Faded Colors in Overglaze Decals is the result of ei
-
ther underfiring or overfiring. If pinks and reds are drab, refire
to a hotter cone. When used with a china paint background, ap
-
ply and fire the decals first, then china paint and fire again.
Check the recommendations of decal supplier. If decal was
underfired, refire to proper firing cone. If decal was overfired,
the design may be repainted in china paints and refired.
Weakening of Luster Colors can be due to overfiring.
Powdering of Luster Colors can be caused by too heavy
an application.
Bisque
Warped Ware can be caused by distorting upon removal of
the piece from the mold, firing too close to the elements, or fir-
ing a piece in an unnatural position. To prevent porcelain cups
or bowls from warping when firing the greenware, edge the top
of a cup with pinches of dry silica or DRY all purpose, high fire
kiln wash and place a second cup on top of the first cup, lip to
lip, with handles going in opposite directions. Porcelain
greenware plates may require firing in plate saggers to prevent
warping during firing.
Glaze
Crazing is usually caused by underfired bisque. Bisque
should be fired to the highest temperature at which it will still
take glaze. Crazed ware may be refired to the proper cone.
CAUTION: China paints and other overglazes will burn off
when fired to 06.
Crazing Immediately on Removing from the kiln can
be caused by not firing the ware hot enough. Refire to the
proper cone. Crazing in spots can be caused by not having
mixed the glaze thoroughly before using.
Porcelain
Bumps in porcelain are usually caused by wet greenware and
overfired porcelain bisque.
Lack of Translucency in porcelain can be caused by the
ware being poured too thick and underfired.
Cracks in porcelain bisque are often the result of a strain on
the greenware while drying. Do not force-dry greenware.
Cracks may be mended with one of the new “magic menders”
available from your supplier.
Kiln Maintenance
Trouble-Shooter
Kiln Does Not Turn On, Display is Blank
I
Make sure the circuit breaker
is in the “on” position.
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Digital Kilns: If the breaker
is on, check the kiln’s fuse. It
is located on the kiln’s switch
box. Remove the fuse by
pressing on the fuse holder
and turning counter-clock
-
wise half a turn. Check the
fuse by placing the probes of
an ohmmeter on the ends of
the fuse. If the ohmeter reads
less than one ohm (digital
meter) or reads 0 ohms (ana
-
log meter), the fuse is bad.
Replacement fuse:
AGC ½ A 250V AC
Note: If you do not have an ohmmeter, visually in-
spect the fuse. You will see a thin strand of unbro-
ken wire in a good fuse. The wire usually appears
broken in a burned fuse, like the filament in a light
bulb.
Circuit Breaker Trips
I
If the circuit breaker trips after the kiln has fired for
awhile, make sure no other appliances are operating on
the same circuit as the kiln. The breaker may need re-
placing.
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If the circuit breaker trips
immediately after the kiln
is turned on, the kiln may
have a short circuit. Un
-
plug the kiln. Open the
kiln switch box and look
for a loose wire touching
the case.
Temperature is
Inaccurate
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Make sure the thermocouple
is pushed 1” or more into the
firing chamber.
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If the temperature is inaccu
-
rate even though the thermo
-
couple extends into the firing
chamber at least 1”, replace
the thermocouple.
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