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Tired of lifting heavy kilns shelves
into the gas kiln? Now there is an economical solution so you don’t
need to strain your back stacking the kiln. Nitride Bonded silicon carbide
shelves are strong and light weight. For example, a 12” x 24” x 1/2”
thick nitride bonded shelf weighs only 14 lbs.! We have
thoroughly tested these shelves in demanding situations with excellent
results. Call us to discuss your application.
Built in Relief
Joints has
been the traditional way these imported shelves have been available. These
relief joints are said to prevent cracking that can occur due to the
repeated expansion and contraction of the shelves during firing.
NEW! No Slits in various
sizes.
Originally all of our
imported Nitride Bonded shelves were manufactured with relief joints,
however we have recently tested some sizes without the slits and the
customer feedback has been excellent. Sizes without expansion joints are
noted as ‘no slits’ in the chart below. They do provide better
strength when handling and storing the shelves.
Tired of having to rotate shelves to
keep them flat? Nitride Bonded silicon carbide may be the answer.
Depending
on the weight stacked on the shelves in combination with the temperature
range, chances are you may never have to rotate them. However, all forms
of silicon carbide do eventually warp (except Advancer). To keep your
shelves in best form, you may have to rotate, but still you will love the
light weight and the ease of removing glaze.
Important Note: We
recommend only 3 post stacking to prevent rocking and provide even
pressure on the shelf from the load above. A 4 post stack is prone to
shifting which results in uneven pressure on the shelf that can cause
cracks. If you are determined to 4 post your shelves, clay wads
should be used to attempt to stabilize the stack; however, because the
clay is viscous the load still may shift and cause cracks.
When you fire thin shelves, you should have
a pyrometer on your kiln so you can be certain that you are not firing too
fast. When a shelf is thin, you have the potential of heating the
outside edges too quickly relative to the inner shelf. If you have
been firing blind with only cones, it won’t tell you how fast you are
traveling between ambient and 100F where you may have a radically fast
heat ramp and not know it.
You can
reduce hours of handling kiln furniture by leaving your furniture
stacked and only replace the wares. The perfectly flat shelf
surface prevents large pots from warping.
Easy to Lift
The nitride bonded silicon carbide shelves are slightly heavier than
Advancer® shelves, but much lighter than High Alumina. Note: Advancer®
is still the lightest and strongest composition shelf available and a much
higher quality, rated for Cone 16. Nitride Bonded is rated for
Cone 11 and may need rotation at some point based on extreme peak
temperature, soak time, and amount of weight placed between the
posts.
We use 1/2” on most sizes because our testing has shown
much improved warp resistance at Cone 11. Our customers have been
very satisfied with the results.
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Want to get more functional height in
your kiln? For every 5 layers of shelves you save anywhere from 3-3/8”
to 2.5” of stacking height compared to conventional 1" shelves.
That can add another shelf layer for every firing. You also reduce the
thermal mass substantially which will result in reduced energy
costs.
Acceptable Tolerances of
Manufacture
The manufacturers of all shelving materials have a factor for
what they consider acceptable manufacturing tolerances and
deviations. A shelf may be perfectly flat when you receive it, or,
it may have a very minor deviation. Nitride Bonded deviation of
acceptability is .5%. This factor is calculated by putting a
straight edge diagonally from corner to corner and measuring a
possible deviation tolerance (if any) in the center of the
shelf. A deviation of this minor degree (.5% of the total length)
does not constitute a "second".
FYI When you receive
an order of nitride bonded shelves to be used in a reduction kiln,
you may want to consider prefiring them to a high temperature
before stacking an actual glaze load. These nitride bonded
shelves can initially cause an extra reduction effect in the
center bottom of pots (i.e., in the area inside the foot)
that may not be desirable. To avoid this problem, just stack a
mock load without pots and prefire them. This will burn out
the reducing agents. One firing is generally all you need to
eliminate this effect.
Receiving and Warranty
It is the purchaser's responsibility to inspect a shipment of
shelves (by UPS or truck) immediately for possible shipping
damage. If damage is found, it must be reported immediately in
order to get compensation from the freight carrier. The
manufacturers of kiln furniture universally do NOT warranty kiln
shelves once they have been fired. Any claim of defect must be
reported before the shelf is fired. In fact, no supplier in the US
warranties kiln shelves.
FYI Cracks that may occur in
a thin nitride bonded kiln shelf are caused by extreme heat
differences across the shelf which are the result of heating or
cooling too quickly. The benefits of the thin nitride shelves
include energy savings, reduced mass in the kiln, and easy
lifting. Understand that because they are thinner, they will heat
up faster on edges that may be exposed to direct heat (such as a
burner flame). This is what may cause a problem for some customers
who have only fired heavier 3/4" or 1" thick shelves
(such as high alumina or cordierite). Thicker shelves take longer
to heat up, and so are less prone to thermal shock. Thin shelves
will be more prone to extreme heating or cooling conditions should
they occur. Therefore, if you are only familiar with firing thick
shelves, you may need to alter your heating or cooling schedule.
Follow the rules, and you will enjoy all the many advantages of
firing with thinner shelves. Contact the Bailey staff for further
tips.
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