Building the Super Thumb 150
A super efficient 100 LB capacity electric pot furnace for the new millennium |
| #1 - The Base |
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| 12ga steel supported by 2" square channel steel and 6 steel casters. |
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| Because the bottom layer of castable is lightweight 1600 deg material, I put these clippers in to keep the weight of the furnace from compressing the softer castable. This formation will distribute the weight onto the steel channels, and has the added benefit of looking like Darth Vader's Tie Fighter (very cool). |
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| Here I wrapped some cheap tin from the hardware store around the steel base and filled with 1600 deg castable up to the top of the clipper bricks. |
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| After the 1600 has set, I put down 2" of 2200 deg castable in a radius equal to the coming brick stack. Then I put down a final layer [2-4"] of Cast-a-lite 30 creating a bowl effect (for glass spillage to collect in so as not to eat away at the soft brick column). |
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| The soft bricks (custom cut for three grooves instead of the normal two grooves. Can you say, POWER) are built up on the high outer ring of the castable, and two clippers are set into the shallow middle for the crucible to later sit on. |
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| Once the brick column is finished (notice the bricks slightly offset from each other for strength), I fill another 6" of 1600 deg castable into the area outside the higher temp castables and about an inch up the outside of the soft brick. |
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| To cover the crucible (a 16" diameter 105# capacity Engineered Ceramics Crucible fits neatly) I had two 12"x24"x3" DP clippers cut to create the gathering hole. I got five years out of the last pair I did this too, and only changed them out to get a clean start for this new furnace. |
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10' of 6# 2" 2200 deg DuraBlanket for the inner ring, and 24' of 2" 4# 1800 deg blanket around that. Notice the notch for the gathering port. [They look so innocent when they're fresh]
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Here I've cut a piece of 1/2" LD frax board to go between the two large cut clippers and the pending crown. Kinda like a gasket.
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| #2 - The Crown |
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This is actually a crude mock up of what later will be a nice metal mold form. The metal pan in the middle is where the lid will end up.
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The bolts hanging into the air space will be the pins that keep the upper metal frame solid enough to be used as both the lid's fulcrum and as a means of easily lifting the crown off for the inevitable maintenance cycle. 4" of 2200 deg castable and then 4" of 1600 deg castable.
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| After removing the crown from the [cheap wood] mold I set up another row of bar and pins for the lid. Hard to see in this photo (but not impossible), but I have a dome that the lid will be casted over to give a slight carving out under the lid to make it easier when removing a gather. 3" of Cast-a-lite 30, 1" of 2200 deg and 3" of 1600 deg to finish off the top. Important note: Line the crown hole with plastic BEFORE casting the lid (it won't work if the lid is one with the crown) |
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Being casted directly into the crown, with the lid fulcrum already in position, insures a perfect fit.
A big improvement over the old lid that could wander slightly left and right.
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The crown settles nicely onto the cut brick's fiber board gasket. I use a fiber paper to make a better seal between the crown walls and the lid.
To attach the lid you just set it in place and gravity does a nice job of holding it from there. |
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Here we see Andy, the proud possessor of ST100 #100-0000-001, demonstrating the smooth action of the lid. [A brick foot pedal is added the next day]
Andy actually did a lot of the work on units 100-0000-001 and 100-0000-002, and said his brother wanted to see him pictured (probably to prove he really did it), so here he is. |
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| #3 Wiring |
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| Text will be added soon! |
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| Cool lens flare, huh? |
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| Power strip |
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| Control Panel, interior shows SCR |
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