Fire pit construction

Old 08-21-12, 07:31 PM
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Fire pit construction

I have a round concrete firepit that I need to insulate. The interior opening is 32" diameter and I have 30" diameter steel ring that fits inside of it. I want to fill the 1" gap with an insulating refractory mix. In my testing the steel ring is only getting to about 450 degrees. Would this mix work sandwiched between concrete and steel? Any problems with my plan? I'd like to keep the concrete below 130 degrees if possible.
Old 08-22-12, 05:14 AM
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Welcome to the forums, Jimmy

I moved your question into its own thread, you'll get a lot more visibility this way than being tacked on the end of a six year old thread.
Old 08-22-12, 05:41 AM
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Welcome to the forum.
I'm assuming this is an outdoor fire pit, not part of any structure?
Local code becomes an issue if this is part of, or near a building.

As for filling the 1" gap, you might be able to get away with filtered sand (beach sand or small granular A). Using Clean dirt should filter the temp reasonable well. The air trapped in the dirt should help with insulating the concrete from the metal.
Maybe others will have other ideas. This is what I can come up with given the assumption this is not near or in a building.
Old 08-22-12, 02:37 PM
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Need more info. How thick is the concrete wall of the fire pit? Is the steel ring attached to it with spacers? What does the bottom look like (thickness, composition, how attached to concrete, etc.)?

I'd be tempted to use a decorative stone or paver material to line the outside of the concrete, while somehow leaving an air space (more steel rings, welded into a lattice-type frame maybe?) between the burning members and the interior concrete surfaces. A larger air gap than just 1" would help dissipate heat better, too.

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