80 |
× |
Ceramic Fiber Insulation Modules
1" thick ceramic fibers oriented perpendicular wall plane. Compressed onto a stainless steel mandrel and banded at 300 PSI. Tightly installed, the bands can be cut while still keeping the insulation under compression. Installation is "finished" off by hammering their kiln-side surfaces with a 2x4 and then spraying them with silica rigidizer to prevent dust. Temperature rated to 2300F.
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40 |
× |
Mullite Tubing - 1" x 40"
These support the Kanthal heating elements. They are almost as strong and heat resistant as alumina, at a fraction of the cost.
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4 |
× |
Insulation Board
This was used as a support for the lower element tubes below the hearth. It is not suitable as wall insulation.
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8 |
× |
Silicon Carbide Hearth Tiles
18" x 18" Recrystallized silicon carbide forms the hearth tiles in 2 rows of 4. It is strong, flat, dora not warp and transmits hear relatively well for a refractory. It is also less susceptable to thermal breakage.
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5 |
× |
Silicon Carbide Beams
The hearth tiles sit on a series of 2"x2"x2' silicon carbide beams which run the width of the kiln.
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10 |
× |
Mullite Posts
The silicon carbide beams sit on a double row of 3" mullite posts which protrude up through the floor insulation. They sit on adjustable screws attached to the steel frame below. One of my personal "discoveries" was that brick insulated kilns have structural walls to help hold things up. Fiber kilns need an additional superstructure to support elements, hearth, etc.
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40 |
× |
Kanthal Heating Elements
Kanthal is an unusual alloy of iron, chromium, and aluminum, that is more resistant to high temperatures than is the more common nichrome. It's special design requirements are that it requires support because it becomes soft at operating temperature, and it is magnetic below 600C.. 12 and 11 AWG wire used.
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24 |
× |
RA330 threaded posts
This is a "space age" alloy used for internal metal components and as welded "wire tails" to attach power leads to the Kanthal elements. In a kiln which might be noted for its use of pricy materials, it was still fabulously expensive.
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16 |
× |
SG-70 Ceramic Fiber Board
This is a nifty composite of alumina and silica fiber. It can be cut and shaped by normal tools. Once it has been fired, it becomes a hard alumina board. I used it to help support the upper elements and to build the 3 view ports.
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8 |
× |
Thermocouples
Inconel clad thermocouples - 18" long. These are type K (required by the controller - type N is better). They are fine at glass fusing temperatures.
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4 |
× |
Quartz Windows
The viewport windows are quartz panes set into the SG-70 viewports. Originally gold coated (light and heat resistance), the gold was eventually removed to improve visibility
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1 |
× |
Watlow CLS208
8 loop ramping PID controller
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1 |
× |
Watlow 84 Watchdog
Over-temperature cutout.
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4 |
× |
Eurotherm 50A SSR
50 amp solid state digital relays are used to control the banks of heating elements.
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1 |
× |
200A relay
Main power cutout, in addition to a fuse-switch disconnector
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1 |
× |
PC laptop
To control the Watlow CLS208
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1 |
× |
Stepper Motor
open and close the cooling vents on the top of the kiln
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1 |
× |
Parallax Stamp
Controls the stepper, under control by the CLS208.
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1 |
× |
A lot of wire and terminal blocks
Of note was the 40' of 8AWG-4 Carol Super Power Cable between the switching cabinet and the kiln halves. (The top moves up and down; the bottom rolls out on V tracks.)
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1 |
× |
Steel: beams, tube, and rolled diamond-perf
Most of the frame is light weight steel tubing and rolled diamond mesh. All ferrous steel; no stainless was used on the main shell.
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2 |
× |
Screw Jacks
2-ton screw lift jacks, powered by a 3/4 HP motor to lift the top of the kiln. They are strong and they don't drop heavy things on you.
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2 |
× |
I-Beams
Kiln frame runs up and down on two 4" I-beams
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1 |
× |
Simulation Software
The kiln's heating element design was simulated on Radtherm (Thermoanalytics)
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1 |
× |
CAD Software
Mechanical design and structural simulation on PTC PRO/Engineer
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