Source for kiln coil support rods?

Drew Riley

Drew Riley

Knifemaker / Craftsman / Service Provider
Joined
Oct 17, 2007
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I’m getting parts together for a new heat treat oven, and I’d like to hang my element from the top similar to how @JTknives did his. I’m looking for a ceramic (or porcelain, or whatever) rod that will span a 6” wide opening, so something like 7”-8” long would be preferred.
Any suggestions on where to look?

btw, would a ceramic honing rod work? Or is that a different material than alumina ceramic used in ovens?
 
Drew Riley said:
btw, would a ceramic honing rod work? Or is that a different material than alumina ceramic used in ovens?
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The ceramic rods are exactly what I am planning to use. They are actually used (as stacy pointed out in another thread) as supports in pottery firing kilns). they are brittle, but with the light weight of the heating element around them I would think they would have no problem supporting a span of 6"
 
Cushing H. said:
The ceramic rods are exactly what I am planning to use. They are actually used (as stacy pointed out in another thread) as supports in pottery firing kilns). they are brittle, but with the light weight of the heating element around them I would think they would have no problem supporting a span of 6"
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I don't see why they shouldn't work, I suppose. I found the exact number I'll need in an ebay listing for about as cheap as I've found them anywhere, so I snagged them. They're a little long, but I'm thinking a diamond wheel on an angle grinder should trim them well enough.

I built my first oven about 12 years ago, and while it's done all I've asked it to, it's been on it's last leg for a while. I never got around to building a shell for it, and the bricks finally caved in a couple nights ago while I was re-arranging the bench it sits on. Better that it wasn't hot I suppose. haha

Hoping to have most of the parts I need to get back up and running again within the next couple weeks.
 
Drew Riley said:
I don't see why they shouldn't work, I suppose. I found the exact number I'll need in an ebay listing for about as cheap as I've found them anywhere, so I snagged them. They're a little long, but I'm thinking a diamond wheel on an angle grinder should trim them well enough.

I built my first oven about 12 years ago, and while it's done all I've asked it to, it's been on it's last leg for a while. I never got around to building a shell for it, and the bricks finally caved in a couple nights ago while I was re-arranging the bench it sits on. Better that it wasn't hot I suppose. haha

Hoping to have most of the parts I need to get back up and running again within the next couple weeks.
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Ceramic is really brittle. Use that diamond wheel to put a little notch (very little) where you want to snap them. Hold in two hands with that notch away from you, and use your two hands to flex the rod at the location of that notch, and they should snap pretty cleanly
 
wkfl said:
Maybe this??
https://www.axner.com/kemper-cbbh-ceramic-bead-bar.aspx
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That looks like it would work too. I did, however, already order some ceramic rods.
Now the problem is going to be finding fire brick. I had a source lined up, but their local distribution center has been closed indefinitely due to market conditions. :( I'm trying to avoid shipping 3 cases of firebrick, as freight will easily double (or worse) the cost of the bricks.
 
There are two types of firebrick One is Heavy One is Light Believe it has to do with the heat rating
Light ones work well! Just sayin
 
Would inconel welding rods work? We use inco for holding up furnace tubes in power plants.
 
Hankins said:
There are two types of firebrick One is Heavy One is Light Believe it has to do with the heat rating
Light ones work well! Just sayin
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Correct. K23 soft bricks are what I’m after. I do believe I’ve found another source as well, close to where I work.
 
Just a little update: I received both my element and the ceramic rods today, and..... the rods are too big to fit the ID of my element. My bad.

That said, I also happened to look up the heat tolerances of various ceramic rods on McMaster Carr's site, and it turns out that certain ceramic rods are only good for up to 1000F or so, and I honestly don't know what kind of ceramic these are. I'll probably just use them to make some custom hones.

So on to plan B: I found some 6.4mm diameter fused quartz rod that I'm going to try. They're good for 2000F or so, which should be plenty for my purposes.
 
Kinda scary ... I would expect (might be wrong) that these whitish rods would be alumina .. should be ok well, well above 1000. I guess we will see though. Quartz is good though, and less brittle I think (?)... just more expensive.

Are you not winding your own elements?
 
Cushing H. said:
Kinda scary ... I would expect (might be wrong) that these whitish rods would be alumina .. should be ok well, well above 1000. I guess we will see though. Quartz is good though, and less brittle I think (?)... just more expensive.

Are you not winding your own elements?
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I bought a pre-wound element with leads.
 
Just refreshed my memory on alumina ceramic - several sources confirm the things are usable up to temperatures of about 3500F. The “formula” for making the stuff Just should not Vary that much (there is a certain ratio of components that needs to be present to make the stuff) ... so if something is truly alumina ceramic, I would expect it to be usable well above 2000F. True that some rods may be called “ceramic” (like the zirconia ceramic on McMaster Carr’s website) .. but anything called “zirconia ceramic” should be able to take the heat ... are you able to find such rods in a diameter that will work for your element?
 
Drew Riley said:
I bought a pre-wound element with leads.
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Alternatively, nichrome wire is really cheap - you can buy the wire and wind your own element (need to pay attention though to the diameter and length of the wire to get the total resistance and surface loading correct....)
 
Cushing H. said:
Just refreshed my memory on alumina ceramic - several sources confirm the things are usable up to temperatures of about 3500F. The “formula” for making the stuff Just should not Vary that much (there is a certain ratio of components that needs to be present to make the stuff) ... so if something is truly alumina ceramic, I would expect it to be usable well above 2000F. True that some rods may be called “ceramic” (like the zirconia ceramic on McMaster Carr’s website) .. but anything called “zirconia ceramic” should be able to take the heat ... are you able to find such rods in a diameter that will work for your element?
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I found some alumina/mullite rods that would work, but they get pricey pretty quick for the 10 feet or so that I’ll need. I found a relatively cheap source for the fused quartz, so I’ll see how that goes.
 
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