Opinions on this flue

[John Kogel]

Does this look like there was a fire in this chimney? The creosote has a glazed look, besides being kinda thick. []

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Another question - To repair a crack in the back of a heatilator-type fireplace, would it be possible to weld this? Vee it out with a grinder and braze it? Or fill it with fireclay?

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[Chad Fabry]

It looks like the chimney had a fairly hearty burn.

Welding the crack will fail at the edge of the weld, but patching the crack after drilling a hole at each end of the crack will probably work OK. Any competent welder will know

what to do.

[kurt]

If it's a heat shield layer, it might not even need to be repaired.

[John Kogel]

If it's a heat shield layer, it might not even need to be repaired.

I suppose that could be determined by probing with a thin wire. Thanks.

[John Kogel]

It looks like the chimney had a fairly hearty burn.

Welding the crack will fail at the edge of the weld, but patching the crack after drilling a hole at each end of the crack will probably work OK. Any competent welder will know

what to do.

Thanks. I thought it looked burnt but pics can be deceiving.

And I realize the cracks like this one can be pretty minor, not a major threat to the occupants. Down low, it might even draw air in to the firebox.

[Jim Baird]

John, I am no chimney expert but I sweep my own flue periodically. It looks like it was blown out by flame but never swept since. I once knew an old carpenter who said his people would periodically stuff, from the bottom up, the whole flue with newspapers, then light it to proactively burn out the creosote.

[Hearthman]

Hard to tell from here but appears to be pyrolized creosote from a flue fire. If it feels like a puff pastry and crumbles in your fingers that's it.

You can get a welder in there but understand it would void any warranty or listing. On a steelform fireplace these are notorious for having combustibles such as paper and wood stuffed in all around them. Applying the heat from welding can ignite such hidden combustibles so beware. If the firebox on a factory built fireplace is cracked or split, recommend full replacement as there is no recognized field repair or replacement unit. Typically, these fireplaces have aluminized steel fireboxes of sheetmetal, approximately 22 gauge. Steelform fireplaces typically use heavier gauge cold rolled steel.

Recommend a full level II inspection.

[mjr6550]

I would say yes to the first question.

For the firebox, I assume it is double wall, or placed in front of masonry. Welding might be an option, but it may crack again in a short time. Fire clay on metal will not stay in place. If it was mine, I would probably put a cast iron fireback in front of it.

Although I hate to refer things to contractors, I would with this since many contractors are likely to say that it cannot be repaired.