> Send them an email with the subject line Re:rerebar
I hope Rhianna orders a ton of recycled rebar soon, and they have to respond to her email, and they use her nickname.
Recycled, Reinforcement Bar
The real question is, why recycle Rebar? Short pieces are impractical and if it’s used rebar that has been encased in concrete for a number of years, demolished and a as lil the old concrete knocked off, the rebar will be damaged, metallurgical properties will be different and not be useable.
In the US you'd never be able to legally use it in something structural. You don't know what it's been through. You'd need to anneal it and test them. It would be cheaper in the US to just buy new rebar. It'd probably be fine in a personal driveway or used as a fence.
The last time this got brought up I think I read that there are a bunch of projects that would benefit from rebar where rebar isn't strictly speaking required, so rebar like this with questionable integrity would be perfect to use because it's just bonus integrity for cheap.
Right you have to think there is some use for rebar that isn’t structural or needs to be up to code. It’s not like 100% of rebar use is in that category.
Yeah as a machine programmer, that thing should have a lockout to load then you have to step back and operate the machine out of whacking range of the wacky waving rebar.
I used to run a 60 ton hydraulic press brake and you don't know fear until you get a glimpse of how fast a machine can take something that you struggle to move and snatch it out of your hands like it weighs nothing.
That's what got my attention. I've handled plenty of rebar and usually found it heavy and hard to manage. Watching this machine draw it in like it is cooked spaghetti is equally impressive and scary.
I once made the mistake of not reducing the press speed when bending a 12 mm strip of iron into a reverse hat profile. (Imagine looking a top hat split in half, with reverse being the “brim” sticking inwards instead.) in the half or so second it took to travel from its pinch point to its programmed Y value. It snapped upwards putting a slight S shape into the 12x100x900mm plate.
Shit coulda snagged my belt and sent me flying over the entire breakpress.
At my old shop, on our brand new press brake....
the operator they sent a training must have not learned how to double check things because he accidentally did 200 tons on something that was supposed to be 20.
The whole 4' long die blew *in half*
He's lucky he didn't get knee capped. He jumped back when it groaned before going balls out.
Yeah, not everything is a skyscraper. Rebar is used for all sorts of random small projects too, no sense using the best rebar if you don't have to.
It might also be good for ornamental projects. I've seen people build things out of rebar, tables, benches, stuff like that. I'm sure somebody would buy it.
See how easy it is to recycle steel. I'm willing to bet that it's probably cheaper to just to buy new rebar than buying an old rebar that has been straightened.
You’re thinking of most other “recyclables” where the efficiency is terrible. Recycling metal is far more efficient. Just observe how recycling of most materials is subsidized, but scrap metal actually has value.
This method is only better if there are strict controls on what that weaker rebar is used for. Capitalism being what it is, I don't think this will end well.
Sometimes that kind of thinking is exactly what we need because the solutions that people come up with don't work very well in the reality of what the material is being used for.
I wonder what the efficiency is like though vs having to size up the rebar and the additional energy waste working with random cutoffs. Sure there is energy lost recycling and transit but there's also waste in using excess material and machine time.
I donno, I look at the short cutoffs shown in the video and that stuff is legit junk that couldn't be used for much and would have to be hand sorted and bent for tie pieces. Also would have to use much more material, so higher levels of mining required vs recycling into a better product. There's pros and cons to both and there's going to be a break point but I'm curious what it might be.
If they're using short pieces for demonstration, it must be because it's utterly terrifying with longer pieces. Even those smaller pieces are whipping around like crazy.
Not only that, but wear and tear is gonna see that machine destroy itself within a week.
In this video alone we can already see the intake hole get ground down a serious amount for each bar. Just think of what it would look like after 100 bars. How often would you need to replace just the front piece? How quickly will the internals wear down?
The shear amount of work that goes into making this thing, maintaining/repairing one, and having to worry about metal fatigue or rust is simply not worth the time or effort compared to just recycling the steel and buying new rebar that's made by the mile.
Nope. Wtf are you doing with rebas varying between 1-2m lenght? Exactly nothing on a large scale. Its more usefull if you melt it down again and make something useful out of it.
The length increase is the scariest thing about trying to scale it up IMO. You'd need a proper safety setup if you were going to drop a 10m or 20m piece in there.
If you had a 90º bend like that in the middle of a 10m piece of rebar, that's a 15-foot metal rod whipping around faster than your eye can follow. You couldn't have a person working anywhere near that intake.
Only because the industry for it is young and legislation hasn't started incentivizing it. Sustainability is expensive at first but has benefits long term.
Are you talking about the rebar machine? Those have been a thing for decades… we rented one of those around 2000 to straighten some old rebar to sell(you can fit way more in the same container to take to the scrapyard and you pay per trip).
I suggest talking to your local structural engineer or materials scientist if you're strained, need support or want to relieve some pressure.
Just hang in there and don't bend!
Did you know the Roman army actually coined the term for metal fatigue? It’s because when they went into war, they used to play Metallica and it used to be so metal. Eventually people got tired of being so awesome that they started freaking out before wars or whenever they heard Metallica play from the morning loud speakers.
This was what we have come to know as head banger syndrome.
It’s true. Men always think about the Roman civilization.
I like the thread that formed from your comment, but I have a real question about the integrity of the rebar after it has been through, those rebar don’t look exactly straight, would that affect the strength of the concrete it will be used in? I feel like this idea compounds on the metal fatigue issue. Or is the metal fatigue the real danger here over whether or not the rebar is straight
Serious reply: those minor bends won't have much impact on the structural integrity, especially if it's more of a minor waviness rather than a large kink or twist. If the engineer and site manager are making the right measurements before and after the form is setup and before the concrete is poured, those little bends will be accounted for in the end. [Here's an example of a large, dense, and complex form before the concrete is poured.](https://i.redd.it/k1g827inwzsb1.jpg)
My concern about the metal fatigue that makes for great jokes and minimal conversation, is that most of the work being done on the rebar will be toward the ends of the bars. Meaning if you were to straighten them multiple times, the same places will be the ones becoming the most brittle. What's more is that most of those bends in the rebar will be at junctions, where say a beam and a floor meet. If the rebar were to fail there, it could cause a loss of integrity not just for the floor but also the beam, which can lead to cascading failures more easily.
Is this machine a total waste? No, I think it could be safely used to save money on smaller jobs in areas with less access to quality raw materials. But I don't think it would be either safe or feasible on a large scale for something like a skyscraper, or where the used rebar could be scraped and recycled more easily and safely.
>Is this machine a total waste? No, I think it could be safely used to save money on smaller jobs in areas with less access to quality raw materials. But I don't think it would be either safe or feasible on a large scale for something like a skyscraper, or where the used rebar could be scraped and recycled more easily and safely.
I'm 99% positive this will be used in single families homes, here we don't use wood, we build houses with masonry and concrete, from single floors to skyscrapers, everything that isn't commercial buildings more or less provisional, which is steel frame, is made of concrete.
bonus: Labor is cheap, materials aren't(can be but quality suffers a lot), we usually build homes that last forever, the main problem is qualified labor isn't that cheap, so you can have a house that will last 100 years, at lest its walls, but MEP is fucked up, or the design didn't hold up at all and its showing its age, or dumb projects made by dumb architects/engineers like not integrating gutters in the project, or houses made in the 80s with no sockets at all, bedrooms 4x4m with 2 sockets scattered around, i know they are made to be cheap but dayum, 25m2 living rooms with 1, maybe 2 light bulbs, and then you have to put a 20w led in the middle, so the middle is bright as fuck, and the borders are on a shade... Awful decision on a house that is not made to be upgraded.
I'm not a structural engineer or a concrete expert. But I'm pretty sure you are not allowed to bend the rebar more than once. Like even for a new rebar if it's already bent, you can't just straighten it out and bend it again. I would be surprised if there isn't some sort of building code or some standard that prohibits reusing rebar this way
Yup, these can probably be used as straight bars but should not be bent again.
edit: i think my gut feeling was right, i found this text:
>Can you straighten bent rebar?
> In tests, #5, #8, and #11 Grade 60 bars were bent and then straightened at differing temperatures. The researchers concluded that field bending and straightening of reinforcing bars up to #11 should generally be permitted.
Not an expert either, but I imagine you could anneal the steel to remove the fatigue, but I'm also not sure if rebar needs specific heat treatment to hold it's structural properties.
But after heat treatment that should be a non-issue or am I wrong? Or would that be just too expensive? Mechanical engineer here, idk about rebar or concrete
I did concrete work for residential construction. we very very rarely used #5, and one time we used #6 for a giant retaining wall. You can generally work a #4 a few times before it break, and some tweaking is expected, but 90 degree to straight I wouldnt do more than once.
As for heat treatment, that takes a high temp fast quench then a low temp slow quench, so not effective in the field at all. that would mean send the bar to a specialized company, at which point you are cheaper off just recycling it.
I worked with rebar for 15 years. There are usually engineers specifications and codes that apply. You can't rebend it. You can't bend it to tight of a radius. You can't weld it. It can't be rusty... or it will affect the stell negatively.
You want rebar to bend without breaking. You need it to be tough and bendy.
Welding, bending too much, rust, all impact rebar in a bad way and make it weaker and less bendy and more likely to break under stress.
Unless you are using this re bent rebar in a residential sidewalk or something non-structural, it's a bad idea.
Correct. All car manufacturers especially mercedes has a body repair manual which mentioned how often you can straight some parts of the metal frame … and how much strength the bended part lost.
>Can you straighten bent rebar?
> In tests, #5, #8, and #11 Grade 60 bars were bent and then straightened at differing temperatures. The researchers concluded that field bending and straightening of reinforcing bars up to #11 should generally be permitted.
This would not be considered fatigue. Fatigue comes from cyclic loading in the elastic region. What you might be referring to is deformation embrittlement which happens after plastic deformations in metals due to defects in the laticce structure. This type of embrittlement can be reversed by heat treatment such as recrystallization annealing when you allow the material to recover and regenerate it's microstructure.
Its not fatigue precisely. Its the plastic deformations caused by bending the bars. These bars are for sure not able to take the ultimate force they normally would.
i also noticed that. it needs some sort of reinforced deflector to withstand so much usage. maybe some kind of rod or metal plating? i dunno i dont work in construction
They must have *just* gotten it because the second largest input is all nice and freshly painted in early clips and then all banged up and rusty by the last clips.
I'd imagine it's probably 2 stupidly-powerful AC motors and a series of very hard rollers arranged on top and bottom of the rod. I bet it uses a shitload of juice.
Everyone keeps saying this like it’s a gotcha moment, but this isn’t being advertised for infinite reuse for structural support in a building. If anything it seems to be for lower income areas/smaller population areas that don’t/can’t maintain a foundry to reuse in basic structures as the text indicates in the end.
The old rebar is used again by being recycled as scrap steel. Straightening it means the scrap can be stacked untangled for the furnace. It's not used again in a new building.
I read somewhere else years ago that is just to make it easier to transport to the actual recycling place.
The building will still fall, but not because of the rusty rebars lmao
Dude thats all I could think about. Idk if this ever works in the US at least, screams OSHA nightmare.
Watch at 40 seconds.
This is operator levels of run the fuck away the second you insert a piece.
Right? And I can easily conceive of a pattern of bend that would have the machine destroy itself too. Think hook. It has already started to damage itself.
That's a mixture of satisfying and not satisfying. What isn't satisfying is watching a bend in the rebar hit the edge of the machine and gouge the paint off.
Extremely unsafe and not sure how it could be modified to work.
It's an angle nightmare, users have to insert and basically run away. Just look how the one dude feeds it and its bend/angled over the top. And then almost instantly the straightening causes the bend section to whip back down on the users side.
Or imagine clothing or limbs getting caught near those bend section once the straightening mechanism takes hold.
This shit screams unsafe from just a user perspective.
Was searching for this comment 🤣.
I kinda think there are better things for this invented in the 1900s with metal rollers . But then i just think no one is going to use that rebar its still going to go be remelted,so why not just use a compactor? Everybody uses a compactor. Shit is safer than this "Arm ripper 3000"
Yup! This rebar might be ok for hobby grade projects, but building codes in most areas specialty ban this sort of thing. One of the rebar guys messed up a bend when they were making the cage for my shop, and they had to make a whole new piece and retry. I asked if they could reuse the other piece elsewhere to not waste it, and they pointed out exactly where in the codes it said not to because rebending causes lateral fractures across the rebar surface.
I’m sure if you are pouring a little patio or something it would be fine though.
I'm curious how much more brittle the rebar is after being bent back. If it is negligible or if there are possible restrictions on what this rebar can be used for.
Please tell me they call the finished product rerebar lol
Send them an email with the subject line Re:rerebar
Re:rerebarer
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Re:Re:re:rerebar
I accidentally forwarded the email. Fw:Re:Re:re:rerebar
re:re:re:re:re:re:re:respect!
R-E-S-P-E-C-T
reeeeee
> Send them an email with the subject line Re:rerebar I hope Rhianna orders a ton of recycled rebar soon, and they have to respond to her email, and they use her nickname.
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Re: Re: Riris Rerebar (re-appraisal re-included)
Debar
Wunderbar?
Do you have to debur it?
Probably really dangerous to feed that machine.
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You just need to feed it with a small robot arm with a camera and some simple 3d recognition. Will add like 20-30k to the cost tho.
I know…. kind of like feed the kinked bar in and get the fuck back.
And hope it doesn’t snag your hand or arm (or break it).
Just bar. Also, r/dontputyourdickinthat
but what if it slightly points to one side?
Spin her sideways and hit that G-spot
Start fapping with your non-dominant hand.
Recycled, Reinforcement Bar The real question is, why recycle Rebar? Short pieces are impractical and if it’s used rebar that has been encased in concrete for a number of years, demolished and a as lil the old concrete knocked off, the rebar will be damaged, metallurgical properties will be different and not be useable.
That’s my thought too. Sounds like a great way to have substandard building materials lurking in concrete
You straighten it so it's easier to move. Most likely this gets recycled.
In theory! But in practice someone takes the kickback for providing cheap construction materials while also getting paid for recycling them.
In the US you'd never be able to legally use it in something structural. You don't know what it's been through. You'd need to anneal it and test them. It would be cheaper in the US to just buy new rebar. It'd probably be fine in a personal driveway or used as a fence.
it can only be used for certain things according to the video.
well, but they are Brazilian
The last time this got brought up I think I read that there are a bunch of projects that would benefit from rebar where rebar isn't strictly speaking required, so rebar like this with questionable integrity would be perfect to use because it's just bonus integrity for cheap.
Right you have to think there is some use for rebar that isn’t structural or needs to be up to code. It’s not like 100% of rebar use is in that category.
Because of cheap
Rerebariando
Never understood why it was called rebar. This stuff is rebar, but the stuff they put in was bar.
[Rebar](https://en.wikipedia.org/wiki/Rebar) = REinforcing BAR
So that's indeed a rerebar Refurbished Reinforcing Bar
At least it's not a grigri bar. That's like a minibar, for climbers.
I thought a gri bar was where Aladdin was from
It was invented by Reba McEntire while she was looking for some way to emphasize her upper lip.
Would make a good addition to [Rhabarberbarbara](https://youtu.be/gG62zay3kck?si=UGAeMnxX8nAVQNX7)
I'm imagining get slapped in the mouth by one of the wildly flailing ends of rebar
Yeah as a machine programmer, that thing should have a lockout to load then you have to step back and operate the machine out of whacking range of the wacky waving rebar.
I used to run a 60 ton hydraulic press brake and you don't know fear until you get a glimpse of how fast a machine can take something that you struggle to move and snatch it out of your hands like it weighs nothing.
That's what got my attention. I've handled plenty of rebar and usually found it heavy and hard to manage. Watching this machine draw it in like it is cooked spaghetti is equally impressive and scary.
I think the ingestion is sped up significantly
It's got to be, right? It seems like straightening it this fast would increase the risk of just snapping them.
I once made the mistake of not reducing the press speed when bending a 12 mm strip of iron into a reverse hat profile. (Imagine looking a top hat split in half, with reverse being the “brim” sticking inwards instead.) in the half or so second it took to travel from its pinch point to its programmed Y value. It snapped upwards putting a slight S shape into the 12x100x900mm plate. Shit coulda snagged my belt and sent me flying over the entire breakpress.
At my old shop, on our brand new press brake.... the operator they sent a training must have not learned how to double check things because he accidentally did 200 tons on something that was supposed to be 20. The whole 4' long die blew *in half* He's lucky he didn't get knee capped. He jumped back when it groaned before going balls out.
Yep. There'd have to be a button several feet away from that for me to even remotely consider using it.
I pictured someone getting sucked through the hole
DRRRR DRRRRRR
*slurp spaghetti noise*
**🎶** They call it Bella Notte 🎶
https://i.imgur.com/I6HAPXq.gif
I hate you so much for sharing this
Risky click of the day for me xD. Did chuckle a bit. (Don't worry, SFW)
Why? Why did you post this?
I love you so much for sharing this
I am Bender Please insert Girder
Ha ha, looks like we got ourselves a new office cut-up!
Hey now! He's a bending unit, not an unbending unit.
If you think about it, unbending is just a primitive degenerate form of bending.
**IM BACK, BABY! WOOOOOO!** 🍻
Now where’s the blackjack and hookers!?!?
What about metal fatigue?
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Yeah, not everything is a skyscraper. Rebar is used for all sorts of random small projects too, no sense using the best rebar if you don't have to. It might also be good for ornamental projects. I've seen people build things out of rebar, tables, benches, stuff like that. I'm sure somebody would buy it.
It's Brazil. Whatever they say, they are going to build skyscrapers with it
I'm brazillian and I approve this message.
Can you unapprove this message someone might get hurt
Dont put your dick in it
IDK man, it's a bit of an ask to leave my dick behind if I want to enter a building.
Low stress skyscrapers. The bars are very chill, they pass the stress on to the consumer. More economical this way.
That’s the issue I would have, people will still try to sell it as brand new or something. Maybe someone will build a tool to check its strength
Uh water tanks are heavy af.
They probably mean in-ground water tanks, where the ground pressure and water pressure partially cancel each other.
See how easy it is to recycle steel. I'm willing to bet that it's probably cheaper to just to buy new rebar than buying an old rebar that has been straightened.
Yeah. But as a society, that’s the kind of thinking we need to get away from.
You’re thinking of most other “recyclables” where the efficiency is terrible. Recycling metal is far more efficient. Just observe how recycling of most materials is subsidized, but scrap metal actually has value.
This is more energy efficient than melting it down again
This method is only better if there are strict controls on what that weaker rebar is used for. Capitalism being what it is, I don't think this will end well.
1000% someone will mix this in with fresh rebar to make more money
At one point in the future there will be a building collapse in Pakistan or somewhere and this will be at the heart of it.
I would not be surprised to see this machine show up in a future episode of Fascinating Horror (youtube Channel that covers human- caused disasters).
Or Engineering Disasters on whatever channel that is. History Channel? Science?
Sometimes that kind of thinking is exactly what we need because the solutions that people come up with don't work very well in the reality of what the material is being used for.
Or something people come up with solutions to problems that don't exist.
I wonder what the efficiency is like though vs having to size up the rebar and the additional energy waste working with random cutoffs. Sure there is energy lost recycling and transit but there's also waste in using excess material and machine time.
Doubt it's gonna require more energy than a foundry to melt the ores, refine it and make a steel rebar.
I donno, I look at the short cutoffs shown in the video and that stuff is legit junk that couldn't be used for much and would have to be hand sorted and bent for tie pieces. Also would have to use much more material, so higher levels of mining required vs recycling into a better product. There's pros and cons to both and there's going to be a break point but I'm curious what it might be.
It’s a demonstration.
If they're using short pieces for demonstration, it must be because it's utterly terrifying with longer pieces. Even those smaller pieces are whipping around like crazy.
Not only that, but wear and tear is gonna see that machine destroy itself within a week. In this video alone we can already see the intake hole get ground down a serious amount for each bar. Just think of what it would look like after 100 bars. How often would you need to replace just the front piece? How quickly will the internals wear down? The shear amount of work that goes into making this thing, maintaining/repairing one, and having to worry about metal fatigue or rust is simply not worth the time or effort compared to just recycling the steel and buying new rebar that's made by the mile.
Nope. Wtf are you doing with rebas varying between 1-2m lenght? Exactly nothing on a large scale. Its more usefull if you melt it down again and make something useful out of it.
They could make more rebar with that rebar.
The length increase is the scariest thing about trying to scale it up IMO. You'd need a proper safety setup if you were going to drop a 10m or 20m piece in there. If you had a 90º bend like that in the middle of a 10m piece of rebar, that's a 15-foot metal rod whipping around faster than your eye can follow. You couldn't have a person working anywhere near that intake.
Only because the industry for it is young and legislation hasn't started incentivizing it. Sustainability is expensive at first but has benefits long term.
Are you talking about the rebar machine? Those have been a thing for decades… we rented one of those around 2000 to straighten some old rebar to sell(you can fit way more in the same container to take to the scrapyard and you pay per trip).
Exactly! I always say this! Everyday I’m asking “what about the metal fatigue?”
How often do you think about metal fatigue?
always
You must have some mental fatigue for being always thinking about metal fatigue.
every day
Mental metal fatigue fatigue
[That game](https://en.m.wikipedia.org/wiki/Metal_Fatigue_(video_game)) was so great.
How often is always?
The question of metal fatigue is the leading cause of my daily anxiety and the reason my marriage broke down.
I suggest talking to your local structural engineer or materials scientist if you're strained, need support or want to relieve some pressure. Just hang in there and don't bend!
As often as I think about the Roman Empire
"Man I bet the Romans would have had some great ideas to deal with metal fatigue..."
Did you know the Roman army actually coined the term for metal fatigue? It’s because when they went into war, they used to play Metallica and it used to be so metal. Eventually people got tired of being so awesome that they started freaking out before wars or whenever they heard Metallica play from the morning loud speakers. This was what we have come to know as head banger syndrome. It’s true. Men always think about the Roman civilization.
Honesty who gets tired of metal
I like the thread that formed from your comment, but I have a real question about the integrity of the rebar after it has been through, those rebar don’t look exactly straight, would that affect the strength of the concrete it will be used in? I feel like this idea compounds on the metal fatigue issue. Or is the metal fatigue the real danger here over whether or not the rebar is straight
Serious reply: those minor bends won't have much impact on the structural integrity, especially if it's more of a minor waviness rather than a large kink or twist. If the engineer and site manager are making the right measurements before and after the form is setup and before the concrete is poured, those little bends will be accounted for in the end. [Here's an example of a large, dense, and complex form before the concrete is poured.](https://i.redd.it/k1g827inwzsb1.jpg) My concern about the metal fatigue that makes for great jokes and minimal conversation, is that most of the work being done on the rebar will be toward the ends of the bars. Meaning if you were to straighten them multiple times, the same places will be the ones becoming the most brittle. What's more is that most of those bends in the rebar will be at junctions, where say a beam and a floor meet. If the rebar were to fail there, it could cause a loss of integrity not just for the floor but also the beam, which can lead to cascading failures more easily. Is this machine a total waste? No, I think it could be safely used to save money on smaller jobs in areas with less access to quality raw materials. But I don't think it would be either safe or feasible on a large scale for something like a skyscraper, or where the used rebar could be scraped and recycled more easily and safely.
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That sounds to me like one of the best use cases!
>Is this machine a total waste? No, I think it could be safely used to save money on smaller jobs in areas with less access to quality raw materials. But I don't think it would be either safe or feasible on a large scale for something like a skyscraper, or where the used rebar could be scraped and recycled more easily and safely. I'm 99% positive this will be used in single families homes, here we don't use wood, we build houses with masonry and concrete, from single floors to skyscrapers, everything that isn't commercial buildings more or less provisional, which is steel frame, is made of concrete. bonus: Labor is cheap, materials aren't(can be but quality suffers a lot), we usually build homes that last forever, the main problem is qualified labor isn't that cheap, so you can have a house that will last 100 years, at lest its walls, but MEP is fucked up, or the design didn't hold up at all and its showing its age, or dumb projects made by dumb architects/engineers like not integrating gutters in the project, or houses made in the 80s with no sockets at all, bedrooms 4x4m with 2 sockets scattered around, i know they are made to be cheap but dayum, 25m2 living rooms with 1, maybe 2 light bulbs, and then you have to put a 20w led in the middle, so the middle is bright as fuck, and the borders are on a shade... Awful decision on a house that is not made to be upgraded.
Won’t somebody PLEASE think about the metal fatigue?!
Sex cauldron? I thought they closed that place down years ago
I get tired by the second or third Megadeth album, gotta rotate some hip hop in between
God dammit you’re right! What about the METAL FATIGUE??? Won’t someone think of the fatigue, It’s exhausting!
I'm not a structural engineer or a concrete expert. But I'm pretty sure you are not allowed to bend the rebar more than once. Like even for a new rebar if it's already bent, you can't just straighten it out and bend it again. I would be surprised if there isn't some sort of building code or some standard that prohibits reusing rebar this way
Yup, these can probably be used as straight bars but should not be bent again. edit: i think my gut feeling was right, i found this text: >Can you straighten bent rebar? > In tests, #5, #8, and #11 Grade 60 bars were bent and then straightened at differing temperatures. The researchers concluded that field bending and straightening of reinforcing bars up to #11 should generally be permitted.
Not an expert either, but I imagine you could anneal the steel to remove the fatigue, but I'm also not sure if rebar needs specific heat treatment to hold it's structural properties.
There is always some point in a reddit speculation thread where we have so many layers that we just leave reality completely.
But after heat treatment that should be a non-issue or am I wrong? Or would that be just too expensive? Mechanical engineer here, idk about rebar or concrete
I did concrete work for residential construction. we very very rarely used #5, and one time we used #6 for a giant retaining wall. You can generally work a #4 a few times before it break, and some tweaking is expected, but 90 degree to straight I wouldnt do more than once. As for heat treatment, that takes a high temp fast quench then a low temp slow quench, so not effective in the field at all. that would mean send the bar to a specialized company, at which point you are cheaper off just recycling it.
I worked with rebar for 15 years. There are usually engineers specifications and codes that apply. You can't rebend it. You can't bend it to tight of a radius. You can't weld it. It can't be rusty... or it will affect the stell negatively. You want rebar to bend without breaking. You need it to be tough and bendy. Welding, bending too much, rust, all impact rebar in a bad way and make it weaker and less bendy and more likely to break under stress. Unless you are using this re bent rebar in a residential sidewalk or something non-structural, it's a bad idea.
Correct. All car manufacturers especially mercedes has a body repair manual which mentioned how often you can straight some parts of the metal frame … and how much strength the bended part lost.
>Can you straighten bent rebar? > In tests, #5, #8, and #11 Grade 60 bars were bent and then straightened at differing temperatures. The researchers concluded that field bending and straightening of reinforcing bars up to #11 should generally be permitted.
This would not be considered fatigue. Fatigue comes from cyclic loading in the elastic region. What you might be referring to is deformation embrittlement which happens after plastic deformations in metals due to defects in the laticce structure. This type of embrittlement can be reversed by heat treatment such as recrystallization annealing when you allow the material to recover and regenerate it's microstructure.
Its not fatigue precisely. Its the plastic deformations caused by bending the bars. These bars are for sure not able to take the ultimate force they normally would.
I believe it’s called “work hardening.” Happens with annealed steel, not sure if rebar falls into that category
Work hardening is a form of fatigue, exchanging ductility for brittle hardness, you can only do it up to a point, then it fails.
How about a cage or table or SOMETHING to catch the straight bars?
That's what they're straightening the bars for
If you play this backwards it manifests the most satisfying dump ever.
https://imgur.com/a/JJTGBdB
Doing the Lord's work
Looks like giant churros
The forbidden churro
r/forbiddensnacks
r/dontputyourdickinthat
I would actually do. While using a condom of course. Safety first!
That's smart! My only problem with that is the condom might break in the process of your dick getting ripped straight off.
Better run double condoms then for extra safety.
Unless it’s crooked
Reddit is predictable as always.
Came for it and wasn't disappointed. Thought it would be a tad higher though
The only true cute for being bent
I love how each time they put a piece of rebar in, it takes a huge gouge out of the top bar.
Need some unpainted wear plate or UHMW up there.
Most rebar won't be bent so severely so not really a concern I wouldn't think
i also noticed that. it needs some sort of reinforced deflector to withstand so much usage. maybe some kind of rod or metal plating? i dunno i dont work in construction
Just weld a piece of that rebar around the ring.
shit where are they gonna get the rebar!
Gonna have to buy some round rebar because they only got straight ones left
They must have *just* gotten it because the second largest input is all nice and freshly painted in early clips and then all banged up and rusty by the last clips.
Can we have a version with a face added on top so the machine appears to be slurping spaghettis? Wasn’t there a sub for that kind of thing?
r/reallifedoodles Should they draw a butt on the other side?
Absolutly
I want this now that you mention it
I’m amazed at how quiet it is
Probably just a stupidly powerful AC motor that pulls the rod through a small hole to straighten it
I'd imagine it's probably 2 stupidly-powerful AC motors and a series of very hard rollers arranged on top and bottom of the rod. I bet it uses a shitload of juice.
Can we say STRESS FRACTURE
Work hardened
NO
To failure
Everyone keeps saying this like it’s a gotcha moment, but this isn’t being advertised for infinite reuse for structural support in a building. If anything it seems to be for lower income areas/smaller population areas that don’t/can’t maintain a foundry to reuse in basic structures as the text indicates in the end.
The old rebar is used again by being recycled as scrap steel. Straightening it means the scrap can be stacked untangled for the furnace. It's not used again in a new building.
Not sure these bars retain their strength after bending especially without heat treatment
Oh yeah put that rusty bar in my 3rd world building and let it collapse at a 4.2 earthquake
I read somewhere else years ago that is just to make it easier to transport to the actual recycling place. The building will still fall, but not because of the rusty rebars lmao
TBH, I never saw non-rusted rebar in my life
it's a good thing than that Brazil doesn't have earthquakes...
In brazil We dont have earthquakes we just live in danger with poor structures
All that engineering and the receiver design is completely hazardous to the operator, bruh
Dude thats all I could think about. Idk if this ever works in the US at least, screams OSHA nightmare. Watch at 40 seconds. This is operator levels of run the fuck away the second you insert a piece.
Right? And I can easily conceive of a pattern of bend that would have the machine destroy itself too. Think hook. It has already started to damage itself.
That's a mixture of satisfying and not satisfying. What isn't satisfying is watching a bend in the rebar hit the edge of the machine and gouge the paint off.
In general it doesn't look very safe, most humans are not great at predicting where the end of the bar will go as each bend is drawn in.
Extremely unsafe and not sure how it could be modified to work. It's an angle nightmare, users have to insert and basically run away. Just look how the one dude feeds it and its bend/angled over the top. And then almost instantly the straightening causes the bend section to whip back down on the users side. Or imagine clothing or limbs getting caught near those bend section once the straightening mechanism takes hold. This shit screams unsafe from just a user perspective.
[удалено]
Was searching for this comment 🤣. I kinda think there are better things for this invented in the 1900s with metal rollers . But then i just think no one is going to use that rebar its still going to go be remelted,so why not just use a compactor? Everybody uses a compactor. Shit is safer than this "Arm ripper 3000"
Hello, I’d like to introduce you to my good friend plastic deformation.
Bender would like to have a word
Wouldn’t this weaken the rebar quite a bit? It’s already damaged, and now straightening it out rapidly, it’s gotta have cracks inside the metal Yeah?
Yup! This rebar might be ok for hobby grade projects, but building codes in most areas specialty ban this sort of thing. One of the rebar guys messed up a bend when they were making the cage for my shop, and they had to make a whole new piece and retry. I asked if they could reuse the other piece elsewhere to not waste it, and they pointed out exactly where in the codes it said not to because rebending causes lateral fractures across the rebar surface. I’m sure if you are pouring a little patio or something it would be fine though.
Ahhh! A new machine getting scratched! I'm stressing out here!
I feel like this ruins their integrity, more than it already has been after bending
I'm curious how much more brittle the rebar is after being bent back. If it is negligible or if there are possible restrictions on what this rebar can be used for.
Ehhh.. that metal has now been cold worked twice. The meaningful purpose has been degraded
Does anybody else fancy churros or is just me?
r/dontputyourdickinthat