Caulking a chimney?

[Black Maple Forge]

Would caulk be a good way to seal a few cracks in a chimney? The fire is right below it, but it is much higher than the fire (still would probably get quite some heat though).

I am only suggesting caulk because it is a very hard to reach area (as it is confined by bricks). Any suggestions would help, Thanks!!

[Trollhammer]

Most hardware stores have little buckets of fireplace patch. Use that with a stick for hard to reach spots maybe? I think Ace Hardware carries the Rutland High Heat stuff in a tube for caulk guns. That might be a better option than just plain old caulking.
Mickey

[divermike]

Trollhammer is correct, make sure to read the directions, some products require fire hardening, meaning you burn a fire within 24 hours of application, be sure that all gaps are sealed, secondary chimney effect has burned down many a structure.

[Frosty]

Use the correct stuff, your chimney is NOT the place to improvise.

Chimney or stack fires are bad enough without INVITING them out for playtime in the walls.

Frosty

[Black Maple Forge]

Would concrete crack sealant work? It says that it is non flammable, non toxic, and weather resistant.

[Glenn]

What are the temperature limits of the concrete crack sealant?

[Black Maple Forge]

It just says non flammable. No specifics...

[Ted T]

Originally Posted by Frosty

Use the correct stuff, your chimney is NOT the place to improvise.

Chimney or stack fires are bad enough without INVITING them out for playtime in the walls.

Frosty

I second what Frosty said.
That is because you may not have a second chance to do it correctly the second time around.
As an investigator for 36 years, many times I have heard the same old stories and statements over and over again from people who were still in shock say things such as the following: "Yes, we knew it was risky, but we didn't think", or "But we thought it would work one more time", or "We planned on changing it later on".
An unwanted, un-controlled fire is something not to be taken lightly!
Please address the issue with professional assistance if need be. It will pay for its self in the end by not having an unwanted fire, and peace of mind.
I keep telling my self to not post my opinion any longer. But when it comes to safety issues..... well! I did .
Ted Throckmorton

[unkle spike]

I would be with Ted, what kind of chimney? How old is it? Is it safe to begin with, or does it need a rebuild, not just a patch?

[Black Maple Forge]

Well, it's not exactly the safest chimney to begin with, but it has a crack that needs filling or else smoke will leak. I think, if I had a long slice, I could apply mortar, but anything else (concrete crack filler?) would be easier.


I have made many fires in it so far, and gotten them up to welding heat. The chimney and everything around it holds up fine. Still, one crack bothers me...





Oh, could I put a little concrete crack filler near a fire to test it's flammability (like put some on the forge's wall, and let it dry, then build a fire)?