The Deadliest Fire Pit Material?

Are concrete fire pits really dangerous? Will they explode? There’s only one way to find out!
Get a pair of Shop Shades safety glasses here (prescriptions available): bit.ly/ftbtsho...
🎥 What to Watch Next:
How to Build the Perfect Fire Pit on a Budget - • Building Your Perfect ...
Building a DIY Smokeless Fire Pit - • Stop the Smoke, Do THI...
➤Tools/Supplies Used (Amazon affiliate):
Our Amazon Shop - amazon.com/sho...
Shop Shades safety glasses - bit.ly/ftbtsho...
Kreg VersaGrip Clamps - amzn.to/46I53uc
Flamethrower - amzn.to/3Z3mZzv
FLIR Thermal Camera - amzn.to/3Z9MOhc
ISOtunes Bluetooth Hearing Protection - bit.ly/2Ru4Es8 (10% off code: FTBT)
➤Support the FTBT Channel:
Buy FTBT Woodworking Plans: fixthisbuildth...
Buy FTBT Merch: bit.ly/2YgiHnd
Links to My Tools & Gear: bit.ly/FTBT-tools
Subscribe: bit.ly/FTBT-you...
➤Join the FTBT Builders Club!!! bit.ly/2abkaSV
More content, early access, FREE plans, video credits
➤Thank you to these partners for supporting our channel. Go check them out!
Kreg Tool: amzn.to/2FXZIGp
ISOtunes: bit.ly/2Ru4Es8 (10% off code: FTBT)
➤FOLLOW FTBT on Social Media:
Instagram - / fixthisbuildthat
Facebook - www. fixt...
Twitter - / fixthisbuildtht
Pinterest - / fixthisbuildtht
Music Licensed through Epidemic Sound - Get a FREE month: bit.ly/3qCwWiW

[@Fixthisbuildthat]

Check out our other Fire Pit videos: How to Make a Smokeless Fire Pit - kzbin.info/www/bejne/oaKpZWCwfJWKadE Easy DIY Fire Pit on a Budget - kzbin.info/www/bejne/pojJl5uOo8mLqJY

[@scottbyrd2157]

As a retired firefighter I’ve seen some crazy stuff regarding various construction materials. Brick, concrete, metal, and wood are common failures during intense fires. In your case concrete can explode and it’s been many injuries from this under extreme heated conditions. But you have to understand that you’re talking excessive heat for longer than 15 mins. Then repaid cooling from water during fire fighting. By far the number one failure of most homes is truss construction roof homes. Simply because the metal fasteners usually pop off that hold the truss system together causing them to collapse like a deck of cards. Most of us say “Never Trust A Truss!” Good video!

[@woodandwheelz]

I'm not an experienced fire fighter, per se, but I did have fire fighter training in the Navy and unfortunately even had to fight a fire out at sea. I was thinking the same things. The tests didn't get hot enough nor were they long enough. Also, having witnessed many fires in my life time, I've seen some of what you've talked about. My first experience was when I was about 6 or 7. A hardware/paint store in Dunedin, FL, caught fire in the early/mid 70's. Even standing as far back as we were, it was super hot. There were multiple explosions during that fire, obviously because of paint cans and hardware store contents, but one of the things I remember was one of the walls exploded then collapsed. Now, looking back, I have no idea if something on the other side exploded collapsing the wall or if the concrete wall exploded. On a good note, other than the loss of his business, no one was hurt in that fire. Thank you for your comment explaining things further.

[@RobertWatkins]

It's not really water seeping in that you need to worry about - if it can seep in, it can escape without building up pressure. What you should be worried about is pockets of water that are sealed in. That's where pressure will build up, and (potentially) explode. The odds aren't great, though - so reproducing this would be tricky. It certainly can happen, though.

[@Fixthisbuildthat]

Yes, great takeaway. Pretty much sums up what I found

[@MrTapanes]

Was at a campsite many years ago on Memorial Day weekend. The campsite had just refurbished a bunch of stuff, including the 'firepits' (really just a 4x4 pad of concrete with a steel fire ring and grill thingie). That first night started off great. But within a couple of hours of campfires being lit, the first one exploded. Everyone rushed over to that campsite and everyone was okay. Minutes later the next one exploded. And so on, etc.. Every single firepit exploded. No one was hurt (miraculously) and it was a very memorable weekend.

[@fununclenerfs]

I feel like this whole upload is an excuse to write off that flame thrower as a 'business expense' ;)

[@sociopathmercenary]

I told my wife it was for killing weeds 😂😂 Edit: Just saw his "flamethrower". That is actually a weed killer. I do have a couple of those but the one I was referencing uses gasoline and is...um... well... More exciting with greater range.

[@beaveroc4688]

Let's all be real. If anyone has an excuse to write-off a flame thrower, we would all take it

[@robdewhirst7525]

Geology grad here. Basalt rhymes with assault. Bubbles from the rocks can be other deposits on the rocks dissolving. That sandstone spalling was awesome to catch on camera. I suspect that without placing the rocks in water under significantly more pressure they won't absorb much water regardless of porosity.

[@johnterry9342]

A friend put his firepit on the driveway to keep warm while handing out Halloween candy. His son pressurewashed their driveway that morning. With the firepit directly on the concrete, there was nowhere for the steam to go. A large explosion blew the firepit ten feet onto the lawn and a significant hole in his driveway. The hole is about 4-5 inches deep and over a foot across. Luckily the shrapnel of the concrete did not injure anyone. I can send a picture if you like.

[@thezfunk]

We had a 40 ft concrete silo. It was abondoned for 30ish years and had no top. My dad decided to fill it with stuff to burn. We lit it up one night and it turned into a towering inferno. Flames out the top and a wind tunnel coming in the bottom. The fire got so hot and turned moisture in the concrete to steam. It blew huge chunks of the silo out at us. When it all burned out we went in to see 4"-6" deep pits in the inside wall.

[@Zenkai76]

that would be amazing to see! from a safe distance of course lol

[@natesteineke9410]

We lost our shop to a fire 2 years ago. My dad and I decided we wanted to save the concrete pad if we could so after we cleaned all the debris and ash we pressure washed it. Out of 2400 sq ft of concrete we only found two small spots where the surface popped loose. One was about 3-4 feet from our waste oil container and the other Im pretty sure we had spilled some oil a few days before. The fire got hot enough it meted the pick up I had parked inside. Didnt really find any new cracks and the popped pieces where pretty small so we kept the old pad for a parking area and still good over 2 years later.

[@Fixthisbuildthat]

That sucks you lost your shop, but thanks for sharing and I'm glad you could at least salvage the pad!

[@waldogtv5486]

I've used blocks and pavers for more than 14 years for various fire pits. Concrete blocks definitely do not stand the test of time, however, they've never exploded, just cracked and fell apart. Never had a single issue with pavers. No explosions or even cracking.

[@NathanielKempson]

Slate has been used for roofing tiles for hundreds if not thousands of years. If it soaks up water.....its probly not slate XD The slate industry in North Wales was MAD, the sheer scale of it boggles the mind. Truly massive.

[@robgullen]

That's nothing like slate as we know it in the UK.

[@NathanielKempson]

@@robgullen DEFINATLY nothing like Welsh slate thats for sure. More like a generic flat rock

[@SamJantz]

I love the irony of testing if things will explode on the firepit made of concrete cinder blocks lol

[@gaffneyman1966]

I was always told that concrete will explode if it has large air pockets. You should pour a block with a ballon inside to test it.

[@needamuffin]

Refactory cement isn't insulative, it's just capable of handling higher temperatures. That's not the same thing.

[@gregsafford]

River/lake rocks in a hot fire can definitely explode with force (from experience). Give a rock years of sitting in water and then expose it to heat... And occasionally you'll find one that lets go in a big way.

[@billparrish4385]

I'm betting the 'sandstone' spalling was due more to heating and expanding the bottom side, which introduced stress between that and the cooler top side not in contact with the flames, and that stress fractured the stone along its crystalline structure. By the time it spalled, all the water should have been roasted out of it, through the relatively slow increase in temperature.

[@justnotg00d]

One point: If you got the rocks from the "creek", then they already have water in them, hence no bubbles. Rocks also contain more than one material, as it was molten at one time. If there are no grains in the slate, which makes it come apart easily, then it is not pure slate. Just a few notes.

[@Fixthisbuildthat]

i should have said from the "dry creek bed". They didn't come out of the water directly. But good point about mixed material rocks

[@Noridin]

Not all rocks were molten.

[@justnotg00d]

@@Noridin Well, I am not quite old enough to have been there. It was my impression from hearing the theories, that the earth was completely molten, then cooled off. As I said, I was not there. My mistake. I do for a fact know that the rocks I have seen (live on a farm that grows rocks) all have a "mix" of different materials and hence that would only happen if they were all molten. I have never seen a sandstone rock that did not have some quartz, some other type embedded in them.

[@Noridin]

@justnotg00d Sandstone is an example of a sedimentary rock that was formed by deposits over time. The point in my comment was that if you're going to correct someone, make sure you are correct yourself.

[@justnotg00d]

@@Noridin Yup. Right after I finished the comment I remembered what a sedimentary rock was. I only have two brain cells left. My point was that no rock I have seen is pure anything. Even diamonds can often have imperfections. And as I said also, I was not there. And I was not correcting anyone. I was just stating my understanding of the formation of the earth, I was not there, but remember in school that the planet was molten at some point. I was saying I don't know, but only what a teacher said. I corrected no one. I admitted that I do not know. So, another point, if you are going to correct someone make sure you understand what they were saying. You can't correct a person that is saying they are not sure of something, that is silly.

[@lisamcclintock219]

This happened to us last weekend, the concrete under the firepit exploded pushing all the burning embers out of the fire in mushroom cloud effect. It was very scary

[@MichaelBuilds]

You should see my fire pit made from Rapid Set… the cap is a crumbly mess lol. Mine doesn’t explode, it pops like popcorn but only when I build a huge fire.

[@xBris]

This is a very useful video for people who only sit at their fire pits for 15 minutes 🙂

[@JaumeAgost]

I saw a concrete floor explode, we were chopping and burning wood in the same spot. It passed two hours and all the sudden there was an explosion that spread all de coals and ashes to a radius of trhee meters, I always wondered if it was a n air bubble below the floor. Also have seen rocks explode, not a big explosion, but we made a firepit from rocks near the river that were completely wet, I coudnt tell you exactly what rocks were, but they seemed sedimentry.Great video, keep up the good work.

[@jaron1990]

Just a quick note regarding 0:36, in water solid molecules are actually further away from each other than in the liquid form 🤷🏻‍♂️🤷🏻‍♂️

[@jeffjackson2871]

When we built our stone patio in 2021 all the research I did said to you use concrete or paver type stones for the fire pit because the natural stone that we used for the patio would crack/explode if exposed to high heat. We used a Pennsylvania Blue Stone for the patio and used uniblock for the fire pit.

[@TheTrullGallery]

Woo hoo, Eagle Scouts!!! I got mine a few years ago - OK, more like 1978... Years ago, while teaching metal shop, I spilled some molten lead on a concrete floor. It caused spalling every time.

[@sampull3541]

1. It’s 212° f 2. Your unexploded/old fire pit is made from CMUs… concrete masonry units. 3. Great video! Love watching your shop vids!

[@Fixthisbuildthat]

Yeah, I biffed the 212 vs 200 F. Whoops

[@sampull3541]

@@Fixthisbuildthat no worries. I wasn’t trying to be a keyboard warrior… love your vids! 👍🏻

[@JCWren]

"Unexploded fire pit". LOL, that's good!

[@triforcelink]

I made a brick fire pit with a concrete base couple of years ago, and have used it probably 3 dozen times. It wasn’t until recently when several concrete chips blew out of the base. Up until then the only damage was the cracking in mortar joints in some spots.

[@larrycox7002]

I once used an oxygen acetylene torch to cut down a heavy steel post set in concrete. Found out the hard way that the heat would cause the surface of the concrete to suddenly explode. I believe it was the sudden heat expansion of the surface while it was still cool underneath the surface.

[@i8saj]

The issue with your tests is how porous the stones, bricks, and even the paver are. The more porous the less water can get trapped & lead to a steam explosion. The crack resistant might actually have more of an issue simply b/c it is less porous.

[@crattis]

Loved the Shop Shades call out. I have the original and the new Dimmers. So worth the money on the Dimmers.

[@handplanepastor8558]

I love this video and think you did a great job at testing things. I do think the amount of time spent testing the blocks might have been extended. I think the average time spent around a firepit would be longer than 15 min and that might impact the outcome. However, two details overlooked would have to do with moisture in the homemade blocks, which you did test but I think need discussing. First, putting out the fires. If concrete is used in firepits and they are doused with water at the end of the night, that could lead to failure and premature failure at that. We have well water that's always nice and cold, so I think it would be more destructive. Second, would be starting a fire in a fire pit that has been exposed to the elements like lots of rain. If a firepit has been exposed to lots of rain, and has been sitting in water or snow for a long period, it could lead to lots of cracks and premature failure. Over all a good video. Thanks for the info!

[@williamellis8993]

Interesting experiment, Brad. As a retired mechanical engineer (note: NOT civil, the concrete experts) I have nothing further to offer. Bill

[@susan_halla]

Love the Tribble on your shirt. 😂 (Great video as always!)

[@calebbewsey9409]

Gonnae be changing the channel name to “Myth this bust that” soon 😂😂

[@BiggMo]

I was taught not to use submerged rocks.. steam can escape from a fast absorbing material, but stones that have absorbed water over decades/centuries are more prone to the problem. Also, using demo’d concrete can be a problem if its a high compression concrete and the fire pit is sitting in a pit of water

[@shanepoindexter2644]

We had an open air trash burner made out of a small concrete pad and cinder blocks with a wire top. We had to replace the wire every 2 years from the heat, the blocks every 10 years and the pad lasted 30 years. But in construction, if there is a structure fire you have to replace all of the basement stem walls and blocks and bricks because their strength is gone. They don't explode, just split and or crumble.

[@28Cryptic743]

what about if you sealed the concrete with something, would that trap the moisture inside and cause it to not be able to escape and that causes it to explode?

[@c.a.g.1977]

This was fun to watch Brad! Very Mythbustery! Mythbusterish? Anyways, fun to watch!

[@Freytraz]

In Brazil, the most common kind of barbecue grill is pre-moulded concrete. People also make traditional concrete wood stoves here and they don't explode. They may crack if they are poorly made, but that is pretty much that and I have made fires hot enough to melt adjacent wires on these grills... The only person I know of who has exploded a grill is myself, but that is because I poured water on the outside of a hot grill. The temperature difference made it literally explode, there were pieces of around half a kilo flying 2~3 meters away...

[@NathanBake]

Never heard about sandstone, but river rocks. I've seen them pop personally, but it's rare and not typically very exciting. They have to have absorbed water that can't escape quickly.

[@johnharp9933]

Good video, but a couple of thoughts. First, I think while extreme heat will not explode concrete doesn’t it weaken it structurally? Don’t know just head that. Second, I grew up in the Ozarks and often concrete was mixed with gravel on site from what ever source. Sometimes the gravel would contain flint as well as sand stone. Even when the sun heated it, I have seen the concrete pop off small pieces from this aggregate.

[@theUcane]

Neat little experiment, Brad. Thank you. Now, how much propane did you blow through to do this? ;)

[@thelunatick1993]

Concrete. How often is the failures occurring with new pours (less than 30 days) vs fully cured vs old pours. What’s the concrete mix. Mix design and admixtures used. Concrete takes time to cure. As it cures, via a chemical reaction, it will lose water moisture. Pavers for fire pits. are likely fully cured before they arrive at the big box store. Mix and admixtures the mfr uses are intended for use. .

[@ArcadianDan]

I think it is the logs/wood that explodes. Not the rocks/stone/concrete/cement. Normally the branches and firewood we use pops and cracks loud when it’s wet.

[@bradfoster5744]

I can and will vouch for the Shop Shades! They are absolutely awesome!!

[@EdgarFroes]

Well, I have a fireplace made out from a washing machine steel barrel. On a cold night, I started it directly on top of the concrete floor. The concrete literally exploded below the steel barrel and it went airborne for about 3 inches, and it was still heavy with some wood still burning in it. And, since I can't seem to learn from my mistakes, it happened a second time with me, the exact same result... Bear in mind that, since it was on the floor, the concrete couldn't expand to the bottom or to the sides, so the built pressure was dissipated to the top.

[@VideoGameVillians]

While your theory about steam pressure causing the rocks/concrete to explode sounds reasonable if the steam was sealed in, I was instantly reminded of glass baking ware that explodes when people put it straight onto a cool counter or put cold ingredients into it while it's hot because of how solids heat/shrink during those temperature changes. If anything was going to do it in a consistent enough manner to expect it on screen here I would think that last one that you through water on would have been it, but still possibly not all types of rock/concrete.

[@firejack007]

We've had problems before with concrete training facilities spalling and injuring FFs.

[@NEWGHOST9]

Moral of the story, if yr gonna build something with extreme heat in concrete, probably best to make sure you line it with firebricks for safety reasons since there has been many reported cases of it breaking apart violently and people getting hurt from it

[@DigitalIP]

Why protect your entire Face when you can just protect your Eyes. Sure, why not.

[@srmofoable]

As a teenager i was melting lead on a painted concrete porch with a propane torch. Eventually a golfball sized chunk about a .25 deep exploded off the surface. I contribute that to thermal expansion causing acute spalling.

[@Fixthisbuildthat]

sounds like something a teenager would do, lol

[@skovbo65]

Freezing is a bigger problem than heat because the water isn't steaming off so there will be more water in the concrete when freezing and water that frease will expand.

[@bryanmartin8336]

We don't hear enough about ShopShades on John's videos. I'm glad that we can now get beaten over the head with them on other videos too.

[@g1mpster]

What information gave you the impression that quick setting concrete would be “more porous”? Genuinely curious because I can’t find anything to indicate this is the case.

[@MCsCreations]

Pretty interesting experiment, Brad! 😃 But I believe you'd want the material that better transfer heat from one side to the other. This way it's going to radiate to whoever is around it. That's the idea, isn't it? I don't really know, here where I live is too hot already. 😬 Anyway, stay safe there with your family! 🖖😊

[@AnyM4jorDude]

Thank you for this video!

[@kennethmiller2333]

Why use the thermal camera? Just ask Chat GPT how hot the rocks are. Porosity is bad in some cases and good in other. The importance is to think about what's going on in the brick, not to say "this is good" or "this is bad." In this case, you have two good options - so dense that no water gets in at all, or so porous that it can't hold the steam. Trying to split the baby is where things end up messy. But it seems concrete mixes remain porous enough to not be a problem. The crack makes sense, though - as the local material comes under tension when it expands.

[@francisR46]

Concrete is brittle. Your block standing alone at the end expanded due to the heat and the water and cracked. A solid circle of concrete sitting outside in the rain and elements that tries to expand builds up pressure under the heat of the fire and eventually something has to give. Whether it ends up just cracking quietly or cracking violently to relieve the pressure.

[@midnightsun2483]

Put a few river rocks in your fire. Very entertaining 😊

[@sapelesteve]

Excellent video Brad. You definitely burned your way through this one! Well done! 👍👍💥💥

[@jacoblittle3693]

I burned one of those easy light logs that you can use for camping on my driveway and it was burning for 2 hours before it blew a perfect circle in my driveway

[@5309backbeat]

We had a poured concrete pit one piece, No cracks for expansion. So we lit our bon fire everything was going great, enjoying our beers when-BOOM sparks everywhere on our clothes on the ground It was scary. So remember leave open cracks for expansion-lol

[@Ammmm18462817mm]

Need a project farm colab!

[@mattelias721]

Interesting test, no doubt. My engineering background tells me that spalling is the usual outcome from well-cast concrete, which is by its nature very fire-resistant. I suspect you didn't get explosions because you couldn't get the materials hot enough, fast enough. My practical experience with this all is, concrete will fail under repeated uses at high temperature (i.e., fire pit temps). It fails very gracefully, but you'll find it kind of erodes. A nice thick layer of that refractory cement over concrete is probably best. Cinder block stuff is really worthless for long-term fire pit ideas, btw. Think of it like cinder ash made into a rice krispy type of treat, except using cement instead of marshmallow. It just eventually disintegrates.

[@christianpoynter7971]

Honestly I feel like sandstone would be one of the least dangerous rocks since it's so soft, it probably couldn't build up enough pressure to truly explode. If there was water in granite or something like that, I would be very concerned. That might turn into a frag grenade.

[@ixilom]

GOTTEM!

[@DarrenMartin-bw8zi]

We would have lots of exploding buildings when firefighters try to put out fires if that were the case... I think.

[@robgullen]

How about using clay bricks that have already been baked when manufactured - they will not crack ... and, err - they make "fire-bricks" for fire backs in fireplaces . . .

[@jamesb5863]

You could have weighed the samples before and after to see what the water evaporation loss was.

[@Griffinwoodworks]

I’m a fellow Eagle Scout. If water can seep in, the steam can seep out the same way, meaning no pressure to be built up, so no boom boom. I’ll need to put a notch in your gorget for that sir. 😂

[@bantcliff]

Taught early on when engineering, you never use an oxy acetylene cutter to cut steel over concrete, always need something under it, it pops and cracks like molten lava if the heat blasts into it. (PS will watch later as F1 Gran Prix is on :)

[@DarrenMartin-bw8zi]

I'm sure you meant Manchester United vs Liverpool is on...😉

[@bantcliff]

@@DarrenMartin-bw8zi that was afterwards, hence I've just now finished up and watched the video :)

[@puwazatza]

I love how your chest hair overgrown so much.

[@ShaunSommer]

Every video I keep looking for the Ghost deer in the background lol

[@msfrat123]

Is that a Luba mower in the background? How do you like it? Will you do a review on that? I’ve been considering one.

[@truthreigns7]

Is your thermal camera just an app on the phone or is a totally different device?

[@critter42]

Did you/do you plan to run similar tests using refractory cement, which is made for use in direct fire applications?

[@compunurse]

I’ve been an Eagle Scout longer than you. In my day, the best way to start a fire with kerosene. Of course we called it magic firewater.

[@boots7859]

Again with the Lets Do It Science, and then stuff it up. The crack-resistant would have been cool since you have a substance that is not inert like a mineral, and for all you know is much worse as it will probably completely degrade at those temperatures... Also, once concrete hits 750', it starts to lose 50-60% of its strength and will start to degrade. Might not be a problem if you are throwing a firepit together from CMUs or such, but if decide to go whole hog and make a really nice fancy one from 40-50 bags, you might find out it looks like crap after several years of fires where you can easily reach 900-1000'. So yea, tehnically it might not blow-up, but concrete and fire aren't a simple thing if you want it to look remain nice looking. And that kiln paint would actually be very helpful as a top-coat/protectant. Its not some sort of insulator.

[@charlestaylor3195]

I believe the exploding fireplace was from an episode of I Love Lucy, or some other popular reran sit-com, because I can remember talking about it with my friends at school the next day.

[@phillyfathead]

Well done!

[@Fixthisbuildthat]

thanks!

[@richardchaven]

steam is invisible. You can see liquid water vapor

[@paininthegrass]

The fire pit being used is concrete block. Doesn’t that answer the question being asked?

[@paulpauba1094]

Aren't you using a fireplace made of concrete cinderblocks?

[@MrJeffdennis]

how long did you let the concrete cure for your tests?

[@Fixthisbuildthat]

Let them cure for 5 days as recommended on the bag 👍

[@SmoothAlf]

Thanks for sharing your crack with us!

[@archangel1824]

Lets see if concrete explodes in fire in my concrete cinder block fire pit.

[@hersir557]

Your firepit is made of pavers but youre forgetring the metal shield covering the inside of the ring. Thats quite not the same

[@Anthony-stama]

Thermal camera apps are not the most accurate from what I hear 👂 but I think Milwaukee makes dedicated cameras

[@Fixthisbuildthat]

It's not an app, it's a dedicated FLIR thermal camera using the phone as the screen. amzn.to/3Z9MOhc The camera clips on the front.

[@Anthony-stama]

@@Fixthisbuildthat oh ok

[@Anthony-stama]

@@Fixthisbuildthat it just looked like an app

[@BenNawrath]

You should hav weighed the mudrock before and after!

[@michaelsa892]

I set a fire on a concrete slab and it blew up under the fire and busted the slab all up

[@oldmanvinny]

That’s the thickest chest hair I’ve ever seen! It even grew through the shirt 😂

[@MCsCreations]

Hey Brad, I'm just starting to watch, but... Isn't it funny how a fire here on Earth doesn't produce more heat than the surface of Venus? 😬

[@schroederb2007]

is that a tc tugger shirt?! (kidding i know its the mic)

[@erikhall9776]

What's with the Taco Bell explosion on the graph? Explosive... LOL.

[@Fixthisbuildthat]

Eat a bunch of TBell and you'll know why it's on the explosive side

[@erikhall9776]

@@FixthisbuildthatYikes. Definitely not my food source goto.

[@kyang321]

@@Fixthisbuildthat Eatthispoopthat

[@ogee_carpentry]

I witnessed a concrete slab explode built into a BBQ, it was not a good day, DO NOT DO IT.

[@somebodyandthem]

You cried?

[@Russianmafia10]

All of the tests should've been soaked in water. Kinda useless to test it dry

[@thewolfman61]

All i know is when i use the cutting torch to close to the floor the molten slag will make the concrete pop and leave little craters

[@Fixthisbuildthat]

Yup, that's spalling.

[@runstrong9559]

science is hard..lol

[@maka5955]

When you make a casting that is too thick, its internal expansion forces will split it strongly. You saw how big the gaps got in the last hot one. If you don't exaggerate the thickness, it will crack without much force.

[@asicdathens]

This is why people use quickset or refractory cement for high temp applications.

[@ThePadadada]

i had concrete explode while brazing a copper pipe near it

[@CU96821]

Im just curious... did it "explode" (boom) (danger) (etc..), or "pop" ?

[@ThePadadada]

@@CU96821 it splintered everywhere about an open hand in diameter and 4 cm deep and it was a sudden burst no crackling before just a violent pop im lucky it didnt hit my eyes could have been bad

[@CU96821]

@@ThePadadada Wow, maybe this should be his next video?? (hint, hint)

[@KY4TRK]

Now pee on it at 700 plus ➕️ degrees...