As A Corollary... (Part 1)

[Sputty]

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[Dick White]

There are reports of adding fiber in that manner will cause the metal jacket, now encased between the original brick inside and the new fiber outside, to corrode at an alarming rate.

[Sputty]

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[Dick White]

And those who are familiar with metallurgy will advise that stainless steel is not necessarily "stainless." It just takes longer and corrodes in its own way.

[oldlady]

dick, also those of us who diligently saved the jacket of a stainless kiln and took it to the metal recycler.  they used a magnet and rejected the " stainless".

[Guest]

A magnet is attracted to 430 Stainless Steel which can pit or corrode. 

 

A magnet isn't attracted 316 and 304 Stainless Steel and won't pit or corrode. Both are more expensive than 430

[Guest JBaymore]

If it is a hex type kiln, the thing that holds the structure of the kiln together is the tension of the metal jacket against the bricks.  If it structurally fails during a firing.... things could get "interesting" fast.

 

Fiber over the steel WILL rot it out very fast as the interface temperature comes up greatly.

 

best,

 

.............john

[Sputty]

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[Marcia Selsor]

It is easy to remove the jacket and put the increased insulation on , then put the jacket back. You may need to add additional length of the "hose clamp" thread to accommodate the thickness of the insulation. It has been done by others.

Marcia

[Pres]

The only place that you could add the fiber insulation would be the lid. This would help with escape of heat. I used a kit lid insulation rig when firing with an L&L years ago in the HS. It had about 3" of fiber with a stainless cover that screwed onto the kiln lid. It cut down the fast fire time, and also helped to slow the cool down. 

 

Now, many years later at home I have replaced the original lid that came with my kiln with a lid that is an inch thicker of firebrick. Two things I notice. The lid does not seem to damage as easily. Cooling is slower by far. I do have two handles on the lid, and do not use a hinge, just lift it off as needed. This allows me to use fewer sections to fire if I wish, or to add the 4th section, which I rarely use anymore. However when I want to fire a really large load, or tall pots it is a nice option.

 

best,

Pres

[Sputty]

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[Sputty]

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[Marcia Selsor]

I need to replace the jacket on my little test kiln. When I do, I should put sone insulation on it as well. The kiln is 20+ years old but in good shape except for the metal. The bottom band had corroded of the base.

Marcia

[oldlady]

marcia, do you remember those top loader electric kilns that were only brick and narrow bands of metal?  i have seen photos in books and magazines (and ebay) but never encountered one in any studio.  it would seem that kind of banding could fit over the bricks and a layer of insulation.  granted, the fiber is exposed but there must be something that could be banded around the whole thing.

[Guest]

 

A magnet is attracted to 430 Stainless Steel which can pit or corrode. 

 

A magnet isn't attracted 316 and 304 Stainless Steel and won't pit or corrode. Both are more expensive than 430

 

I eventually remembered to take a magnet out to my kiln - no attraction there, so presumably it's a better grade of stainless steel.

Does that mean I can get away with gluing fibre to the outside after all, I wonder?

Although I have read that stainless steel can be irreversibly sensitised to corrosion by excess heat (400 - 800 deg C, - 750-1550 deg F). I suppose effectively sandwiching it between a layer of insulating brick and another layer of fibre will elevate the temperature somewhat... so maybe not after all!

 

 

I really don't know, I wonder if an air space between the jacket and insulating fiber would work?

[Sputty]

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