My Chimney Exploded!

Swine Spectator · Jul 29, 2012

Tonight I was going to practice making chicken lollipops. I filled my chimney with Outdoor Gourmet charcoal (from Academy Sports) and lit it. I went inside to work on the lollipops. When I came back out, my chimney was laying on it's side and lit coals were spread over a three-foot radius. Upon closer investigation, I discovered chunks of concrete mixed with the coals.

There is a circular pit (~1/2" deep) in the concrete that is the same diameter as the chimney. It appears that the heat of the chimney caused the concrete below to explode.

I was able to collect the coals with tongs and proceed with the cook. No one was harmed, but the whole thing kinda freaked me out. What if the kids had been in the backyard?

Has anyone experienced this?

David
The Swine Spectator

mmmmeat · Jul 29, 2012

yuppers, same reason they tell us not to weld on concrete...weld metal on top of concrete... with oxy torch specifically... big badda boom

Boshizzle · Jul 29, 2012

Yep, that cam happen.i use a cinder block under my chimney or just sit it on the charcoal grat to start the fire.

jlondon · Jul 30, 2012

wow, never heard of that happening before. Would freak me out too. I always place my chimney on the firebox grate.

Butt Rubb'n BBQ · Jul 30, 2012

Was it fresh or wet concrete. We built a cinder block smoker on a concrete slab and lit a fire in it before it had cured and the thing blew up like a atomic bomb. The expansion of water will blow concrete up.

El Presidente · Jul 30, 2012

Yeah I've had this happen too. The concrete can't handle that high of temperature. I start my chimney in the grill now and rest it on paver stones until cool.

Sent from my LG-E739 using Tapatalk 2

NorCalQue · Jul 30, 2012

What MMmmmmm-eat said.

I put my chimney on two fire-bricks. If I get another weber grill someday

I'll fire it up on it.

That cinderblock is a great idea, get it even farther off the deck.

Skidder · Jul 30, 2012

I would think it's caused by trapped air expanding in the concrete

Wesman61 · Jul 30, 2012

Yep, I found that out the first time I used a cutting torch to remove a piece of metal from an expansion joint in the warehouse of a company I worked for. A forklift driver hit the angle iron with a fork and bent it upward. I thought "no problem. I'll just cut it off with a torch." Snap, crackle, pop.

Swine Spectator · Jul 30, 2012

I have lit my chimney on this slab a 100 times. The slab is >50 years old, but it has rained a lot the past few weeks. Fortunately, I was planning to have it removed in two weeks, so I don't have to worry about the crater.

David

Terry The Toad · Jul 30, 2012

Along these same lines... if you are camping, I've read that you should not line a firepit with damp stones. The moisture inside turns to steam and BOOM! :shock:

Bludawg · Jul 30, 2012

Concrete is porous and retains moisture, a concentrated heat source will cause the trapped moisture to boil generating steam pockets, as the stem expands it builds pressure hence Ka Boom... charcoal chimney mortar:becky:

bbqbull · Jul 30, 2012

Bludawg said:
Concrete is porous and retains moisture, a concentrated heat source will cause the trapped moisture to boil generating steam pockets, as the stem expands it builds pressure hence Ka Boom... charcoal chimney mortar:becky:

The technical term is called...Spalling.

When my son's pole barn burnt down a few years ago it damaged his concrete floor. So bad they had to break it up and haul it away.

He had just purchased several cases of motor oil and stored it in his barn.

tish · Jul 30, 2012

I light my chimney sitting on the grate in my Keg, but have been known to lay it down on the concrete for short periods if I've had to remove the grate to rearrange the lump underneath before dumping the chimney's contents on top. That's pretty scary. Thanks for the warning. :shock:

dadsr4 · Jul 30, 2012

tish said:
I light my chimney sitting on the grate in my Keg, but have been known to lay it down on the concrete for short periods if I've had to remove the grate to rearrange the lump underneath before dumping the chimney's contents on top. That's pretty scary. Thanks for the warning. :shock:

If it's only a few seconds, should be no problem. Just don't leave and come back. The OP was gone for a while. Still safer not to though.

colonel00 · Jul 30, 2012

Sadly I have to admit that I have made this mistake as well. I lit a chimney of lump and left it on the drive for a while. Pop!

FashionBiff · Jul 30, 2012

I think I heard this before but wow, good to get the refresher. My wife and I have a PITA Jack a poo so I always light my starter on another grill to keep the pooch safer, I think that is the only reason I keep my aussie grill around.

jestridge · Jul 30, 2012

That a question on my safety test is it ok to weld or cut on concreteT/F

Smokendink71 · Jul 30, 2012

I've actually had this happen also, I bought a flat cast iron skillet at a garage sale and now use it to set my chimney on when lighting, works great

VoodoChild · Jul 30, 2012

I got A Smokey joe off Cl just for the Chimney !!! I really Did . :blah::blah::blah::clap2::loco:

My Chimney Exploded!

is Blowin Smoke!

is Blowin Smoke!

somebody shut me the fark up.

Knows what a fatty is.

Take a breath!

Well-known member

NorCalQue

Guest

Babbling Farker

is Blowin Smoke!

is Blowin Smoke!

is one Smokin' Farker

somebody shut me the fark up.

Watching over us.

Quintessential Chatty Farker

somebody shut me the fark up.

Quintessential Chatty Farker

Full Fledged Farker

somebody shut me the fark up.

Full Fledged Farker

is one Smokin' Farker

Similar threads