When you weld two pieces of steel together, unless the steel is Super Fancy the weld itself is actually stronger (though more brittle) than the steel it's holding together
So the weld can crack in certain circumstances, but often your ultimate failure is next to the weld, which is a gigantic pain in the ass
And if you're welding temporary fixtures to hold something up you have to be careful and actually cut them off, because if you try and be Smartass McCoolguy and just bang the weld free with a sledge you tear the shit out of the steel
How can something be stronger but more brittle? I can't get my head around that.
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RankenphilePassersby were amazedby the unusually large amounts of blood.Registered User, Moderatormod
I would also love to learn more about creating basic circuits, but I am fucking awful at soldering
mainly I just want someone to pay all my bills so I can spend all of my time making an entire tiny little fantasy midieval city with windows that light up and little secret passages and an intricate series of sewer tunnels that connect to each other and link into a collapsed ancient dwarven ruin that is now filled with the restless dead
When you weld two pieces of steel together, unless the steel is Super Fancy the weld itself is actually stronger (though more brittle) than the steel it's holding together
So the weld can crack in certain circumstances, but often your ultimate failure is next to the weld, which is a gigantic pain in the ass
And if you're welding temporary fixtures to hold something up you have to be careful and actually cut them off, because if you try and be Smartass McCoolguy and just bang the weld free with a sledge you tear the shit out of the steel
How can something be stronger but more brittle? I can't get my head around that.
Because that's how it works
Steel is more brittle than rubber
You (in most cases) trade off strength for flexibility
Metal has a grain like wood. When a part is formed the grain direction is in the direction it was formed. When cracks occur, they will often follow the grain direction.
Copper, brass, and steel sheet metal usually don't have a single grain direction because of the manufacturing process. Titanium and aluminum almost always have a definite grain direction unless annealed, due to their manufacturing process.
When manufacturing parts with metal that has a grain, you have an increased chance of it cracking along that grain unless you work it counter to the grain direction.
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RankenphilePassersby were amazedby the unusually large amounts of blood.Registered User, Moderatormod
"Strong" is an arbitrary term. Meaningless, in reality.
Some things are more flexible than others.
Some things are more resistant to stretching, or compression, or twisting, or any number of other stresses.
Brittle just means weak vs shattering or shearing.
Flexible just means strong vs flexing, bending or twisting, usually.
Strong is too vague to be of much use when you're dealing with materials.
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MachwingIt looks like a harmless old computer, doesn't it?Left in this cave to rot ... or to flower!Registered Userregular
When you weld two pieces of steel together, unless the steel is Super Fancy the weld itself is actually stronger (though more brittle) than the steel it's holding together
So the weld can crack in certain circumstances, but often your ultimate failure is next to the weld, which is a gigantic pain in the ass
And if you're welding temporary fixtures to hold something up you have to be careful and actually cut them off, because if you try and be Smartass McCoolguy and just bang the weld free with a sledge you tear the shit out of the steel
How can something be stronger but more brittle? I can't get my head around that.
Brittleness (and ductility) are measures of how a material performs under repeated forces, which aren't necessarily the breaking force of the material. The best example is a paperclip: straighten one out, and then bend it back and forth repeatedly. After a couple times, it'll break. Why didn't it break the first or second time, when you were applying the same force?
The reason is that stresses in a material aren't uniform. Shear forces tend to put the most stress on the center of a cross-section of a material, while bending forces put the most stress on the outer parts. As small part of the cross-section yields, the force it was supporting before is redistributed in certain ways. In ductile materials like unwelded steel (or a paperclip), a yielded portion can still support a force; the molecular bonds have shifted such that yielded steel stretches more, but the bonds are still there, so only some of the force is redistributed. In brittle materials like concrete, you get cracks. Since no tensile force is transferred across a crack, the stress is immediately redistributed to other parts of the material, and you get a quicker (i.e. more catastrophic) failure.
Metal has a grain like wood. When a part is formed the grain direction is in the direction it was formed. When cracks occur, they will often follow the grain direction.
Copper, brass, and steel sheet metal usually don't have a single grain direction because of the manufacturing process. Titanium and aluminum almost always have a definite grain direction unless annealed, due to their manufacturing process.
When manufacturing parts with metal that has a grain, you have an increased chance of it cracking along that grain unless you work it counter to the grain direction.
Also cool metal fact
You can control the crystallization of a cast metal to prevent grain lines and subsequent heat growth and fatigue cracking, important in parts with critical tolerances like turbine blades
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Donovan PuppyfuckerA dagger in the dark isworth a thousand swords in the morningRegistered Userregular
If you want to know more about this kind of stuff (steel is crystals!), a book I re-read quite often is this. I got it as part of the book requirement when I was studying aircraft mechanical engineering at TAFE (basically Australian community college), and it explains a great deal about metals, plastics, wood, concrete and their uses in engineering. It's more of a primer than an in-depth textbook, so it's easy to read and isn't 950 pages. By the end you'll know the difference between Austenite and Martensite! And why cast iron is a MOTHERFUCKER to weld! There is newer version that I have no personal experience with, so I don't know what they've changed/added in.
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#pipeCocky Stride, Musky odoursPope of Chili TownRegistered Userregular
and also I really really wish I had a fucking garage that I could use as a workshop
I lust after space soooo bad
Welding is super easy
welding well is super hard.
Luckily if you have time, you can just go crazy and just fucking soak your welds and then grind it clean. To get a good, clean, strong weld in a single pass takes a shitload of practice.
I've been watching a lot of videos by this dude in the Schola Gladitoria who practices HEMA (Historical European Martial Arts) and is an amateur historian/anthropologist
He answers a lot of myths about weapons and their use in a nicely informative way without sensationalizing anything
I've been watching a lot of videos by this dude in the Schola Gladitoria who practices HEMA (Historical European Martial Arts) and is an amateur historian/anthropologist
He answers a lot of myths about weapons and their use in a nicely informative way without sensationalizing anything
"Strong" is an arbitrary term. Meaningless, in reality.
Some things are more flexible than others.
Some things are more resistant to stretching, or compression, or twisting, or any number of other stresses.
Brittle just means weak vs shattering or shearing.
Flexible just means strong vs flexing, bending or twisting, usually.
Strong is too vague to be of much use when you're dealing with materials.
Pedant time
Strong is usually referring to yield strength, which is the lowest possible applied force/area that causes permanent deformation. So it is legitimately a number!
But it's also based on application--if you want something that you can load the fuck out of, you want a material with a very high compressive strength; if you want something that you can pull on or hang something from, you want a material with a high tensile strength. That's where you get into different alloys of steel and aluminum for different purposes.
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#pipeCocky Stride, Musky odoursPope of Chili TownRegistered Userregular
Yeah I always understood "Strength" to be like "Power", it has a specific scientific definition, it just isn't applicable in all the ways you'd use it in normal speech
That is strength, boy! That is power! What is steel compared to the hand that wields it? Look at the strength in your body, the desire in your heart! I gave you this! Such a waste. Contemplate this on the tree of woe.
LuvTheMonkeyHigh Sierra SerenadeRegistered Userregular
Hey metal nerds
What would be involved with getting a tube for a telescope made out of, say, aluminum? Something that sort of looks like this
I don't even own a telescope of my own yet, this is more of a theory thing. I have seen many posts while researching a telescope purchase about DIY scopes and I'm wondering how they do it
MachwingIt looks like a harmless old computer, doesn't it?Left in this cave to rot ... or to flower!Registered Userregular
edited May 2014
You wanna know what's really neat? Structural fuses!
Basically, the idea is that you want your building to fail in an earthquake, but in a pre-determined spot. The reason is that failure dissipates energy. An earthquake is going to dump a certain amount of energy into your structure, and while your building acts elastically (i.e. pre-failure), all that energy does is just bounce around inside. The structural elements might be intact so far, but things like partition walls and HVAC (and the people inside!) are going to get knocked around and probably break. The only way this energy is going to disappear is through friction, and that can take many dozens of back-and-forth movements of the building, which can be bad news for your more brittle structural elements.
A structural fuse, on the other hand, eats energy quickly. Steel dissipates kinetic energy by heating up quite a bit when it yields. So, engineers on things like modern highrises and bridges (the new bay bridge being an excellent example) will add big plates of steel and design the structure such that those plates are guaranteed to undergo the most deformation, and therefore experience the most force, in the event of an earthquake. Once the danger is over, you can go in and unbolt the old, torn up plates and replace them with new ones~
"Strong" is an arbitrary term. Meaningless, in reality.
Some things are more flexible than others.
Some things are more resistant to stretching, or compression, or twisting, or any number of other stresses.
Brittle just means weak vs shattering or shearing.
Flexible just means strong vs flexing, bending or twisting, usually.
Strong is too vague to be of much use when you're dealing with materials.
Pedant time
Strong is usually referring to yield strength, which is the lowest possible applied force/area that causes permanent deformation. So it is legitimately a number!
But it's also based on application--if you want something that you can load the fuck out of, you want a material with a very high compressive strength; if you want something that you can pull on or hang something from, you want a material with a high tensile strength. That's where you get into different alloys of steel and aluminum for different purposes.
I think we need a separate metallurgy thread so you can drop some knowledge on us.
What would be involved with getting a tube for a telescope made out of, say, aluminum? Something that sort of looks like this
I don't even own a telescope of my own yet, this is more of a theory thing. I have seen many posts while researching a telescope purchase about DIY scopes and I'm wondering how they do it
My dad's done DIY scopes by both cannibalizing lesser scopes he thrifted and by using PVC pipes. I can ask him if he knows where to find a tube like you're talking about if you want. He's really into amateur astronomy.
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RankenphilePassersby were amazedby the unusually large amounts of blood.Registered User, Moderatormod
Like, one thing I have been wanting to do is experiment with making large sculpture work using styrofoam and bondo
but that requires large amounts of space
that I do not have
also, I want to make entire modular cityscapes
I am super good at using insulation foam for creating miniature brickwork, ruins and all kinds of interesting structures
but I have no place to store them, let alone work on them
fuuuuuck I need a workshop so bad
Go on Google and look up "Maker space [your city" and "hacker space [your city]"
They're spaces created by people with the same problem.
yeah, I know
I'm in Seattle, there's a bunch of them
but I want one attached to my house, so I can just go noodle around in my spare time whenever I get a few minutes or take an entire weekend to just hammer away on a project
It wasn't! It was just less epic and more pulpy than the original Schwarzenegger one. My one friend who is as close to a Robert Howard scholar as you can get absolutely adored it, and it's a snappy flick with a lot of fun in it.
Plus the female lead punches out the female antagonist in an incredibly satisfying way.
Downside: The original Conan's soundtrack is one of the best ever and the new one was not even close.
I'd heard the name "hogan's heroes" before and assumed it was actually a show from the late 80s or early 90s starring one Hulk Hogan leading a group (probably of other wrestlers I guess?) on incredibly cheesy action adventures
Unlike traditional welding, which adds material, FSW just squishes the existing material together by softening it and swirling it around like you were stirring peanut butter in a jar
I've been watching a lot of videos by this dude in the Schola Gladitoria who practices HEMA (Historical European Martial Arts) and is an amateur historian/anthropologist
He answers a lot of myths about weapons and their use in a nicely informative way without sensationalizing anything
I'm not knowledgeable so he could be making this shit up but he always sites and has extremely reasoned arguments and isn't a dick
He seems pretty rad
That is always the problem! It is so hard to separate the truth from fiction online at times. I have pretty much given up on reading anything written in English about medieval Japan because of this.
The video you linked seems pretty solid though. He seems logical and well reasoned, which instantly makes him better than 99% of the discourse online about historical arms and armor. I will end up watching more of his stuff, I think. Sometimes people like him or Lindy Biege (who he mentioned in that video) make conclusions that seem logical but often we are working with incomplete or biased data pools, so it is hard. Curious to see if he has any stuff about rapiers and if it gels with stuff I have learned from other sources. Of course, the thing with HEMA too is that even previously established interpretations of the manuals are revisited, questioned, revised, etc and sometimes what people thought turned out to be totally wrong. Which is part of what makes it exciting!
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The GeekOh-Two Crew, OmeganautRegistered User, ClubPAregular
Last night I found out that hogan's heroes was actually a tv show from the 60's about prisoners in a nazi POW camp who are led by a soldier named Hogan in a series of hilarious escapades that constantly undermine the nazi army
I'd heard the name "hogan's heroes" before and assumed it was actually a show from the late 80s or early 90s starring one Hulk Hogan leading a group (probably of other wrestlers I guess?) on incredibly cheesy action adventures
I liked my Hogan's Heroes better, I couldn't really get into "nazi pow hijinks"
I've been watching a lot of videos by this dude in the Schola Gladitoria who practices HEMA (Historical European Martial Arts) and is an amateur historian/anthropologist
He answers a lot of myths about weapons and their use in a nicely informative way without sensationalizing anything
I'm not knowledgeable so he could be making this shit up but he always sites and has extremely reasoned arguments and isn't a dick
He seems pretty rad
That is always the problem! It is so hard to separate the truth from fiction online at times. I have pretty much given up on reading anything written in English about medieval Japan because of this.
The video you linked seems pretty solid though. He seems logical and well reasoned, which instantly makes him better than 99% of the discourse online about historical arms and armor. I will end up watching more of his stuff, I think. Sometimes people like him or Lindy Biege (who he mentioned in that video) make conclusions that seem logical but often we are working with incomplete or biased data pools, so it is hard. Curious to see if he has any stuff about rapiers and if it gels with stuff I have learned from other sources. Of course, the thing with HEMA too is that even previously established interpretations of the manuals are revisited, questioned, revised, etc and sometimes what people thought turned out to be totally wrong. Which is part of what makes it exciting!
He references treatises constantly and mentions there are lots of interpretations
I've been watching a lot of videos by this dude in the Schola Gladitoria who practices HEMA (Historical European Martial Arts) and is an amateur historian/anthropologist
He answers a lot of myths about weapons and their use in a nicely informative way without sensationalizing anything
I'm not knowledgeable so he could be making this shit up but he always sites and has extremely reasoned arguments and isn't a dick
He seems pretty rad
That is always the problem! It is so hard to separate the truth from fiction online at times. I have pretty much given up on reading anything written in English about medieval Japan because of this.
The video you linked seems pretty solid though. He seems logical and well reasoned, which instantly makes him better than 99% of the discourse online about historical arms and armor. I will end up watching more of his stuff, I think. Sometimes people like him or Lindy Biege (who he mentioned in that video) make conclusions that seem logical but often we are working with incomplete or biased data pools, so it is hard. Curious to see if he has any stuff about rapiers and if it gels with stuff I have learned from other sources. Of course, the thing with HEMA too is that even previously established interpretations of the manuals are revisited, questioned, revised, etc and sometimes what people thought turned out to be totally wrong. Which is part of what makes it exciting!
"Strong" is an arbitrary term. Meaningless, in reality.
Some things are more flexible than others.
Some things are more resistant to stretching, or compression, or twisting, or any number of other stresses.
Brittle just means weak vs shattering or shearing.
Flexible just means strong vs flexing, bending or twisting, usually.
Strong is too vague to be of much use when you're dealing with materials.
Pedant time
Strong is usually referring to yield strength, which is the lowest possible applied force/area that causes permanent deformation. So it is legitimately a number!
But it's also based on application--if you want something that you can load the fuck out of, you want a material with a very high compressive strength; if you want something that you can pull on or hang something from, you want a material with a high tensile strength. That's where you get into different alloys of steel and aluminum for different purposes.
I stand corrected!
I fuckin love these sorts of threads.
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NocrenLt Futz, Back in ActionNorth CarolinaRegistered Userregular
Being friends with a machinist mate and hull technician, I learned a lot about welding and I already got some schooling on circuitry. Would love to have the space to work with it though so I can make some kick-ass 40K terrain.
Posts
... maybe it would if i had a garage.
but that requires large amounts of space
that I do not have
also, I want to make entire modular cityscapes
I am super good at using insulation foam for creating miniature brickwork, ruins and all kinds of interesting structures
but I have no place to store them, let alone work on them
fuuuuuck I need a workshop so bad
I can weld steel just fine!
Aluminum is another story entirely
Could scrapped most of our practical shit and done about three more weeks on lathing, frankly. Would have come in way more handy.
How can something be stronger but more brittle? I can't get my head around that.
mainly I just want someone to pay all my bills so I can spend all of my time making an entire tiny little fantasy midieval city with windows that light up and little secret passages and an intricate series of sewer tunnels that connect to each other and link into a collapsed ancient dwarven ruin that is now filled with the restless dead
because I totally fuckin' know how
this is one of the skills that I have
Because that's how it works
Steel is more brittle than rubber
You (in most cases) trade off strength for flexibility
Metal has a grain like wood. When a part is formed the grain direction is in the direction it was formed. When cracks occur, they will often follow the grain direction.
Copper, brass, and steel sheet metal usually don't have a single grain direction because of the manufacturing process. Titanium and aluminum almost always have a definite grain direction unless annealed, due to their manufacturing process.
When manufacturing parts with metal that has a grain, you have an increased chance of it cracking along that grain unless you work it counter to the grain direction.
Some things are more flexible than others.
Some things are more resistant to stretching, or compression, or twisting, or any number of other stresses.
Brittle just means weak vs shattering or shearing.
Flexible just means strong vs flexing, bending or twisting, usually.
Strong is too vague to be of much use when you're dealing with materials.
Brittleness (and ductility) are measures of how a material performs under repeated forces, which aren't necessarily the breaking force of the material. The best example is a paperclip: straighten one out, and then bend it back and forth repeatedly. After a couple times, it'll break. Why didn't it break the first or second time, when you were applying the same force?
The reason is that stresses in a material aren't uniform. Shear forces tend to put the most stress on the center of a cross-section of a material, while bending forces put the most stress on the outer parts. As small part of the cross-section yields, the force it was supporting before is redistributed in certain ways. In ductile materials like unwelded steel (or a paperclip), a yielded portion can still support a force; the molecular bonds have shifted such that yielded steel stretches more, but the bonds are still there, so only some of the force is redistributed. In brittle materials like concrete, you get cracks. Since no tensile force is transferred across a crack, the stress is immediately redistributed to other parts of the material, and you get a quicker (i.e. more catastrophic) failure.
Also cool metal fact
You can control the crystallization of a cast metal to prevent grain lines and subsequent heat growth and fatigue cracking, important in parts with critical tolerances like turbine blades
Welding is super easy
welding well is super hard.
Luckily if you have time, you can just go crazy and just fucking soak your welds and then grind it clean. To get a good, clean, strong weld in a single pass takes a shitload of practice.
Need some stuff designed or printed? I can help with that.
Do you know about the secret folding techniques the swordsmiths of glorious nippon used to create the finest swords ever made?
I love this guy's Videos
I always watch the new ones these days
Like
I'm not knowledgeable so he could be making this shit up but he always sites and has extremely reasoned arguments and isn't a dick
He seems pretty rad
Go on Google and look up "Maker space [your city" and "hacker space [your city]"
They're spaces created by people with the same problem.
Pedant time
Strong is usually referring to yield strength, which is the lowest possible applied force/area that causes permanent deformation. So it is legitimately a number!
But it's also based on application--if you want something that you can load the fuck out of, you want a material with a very high compressive strength; if you want something that you can pull on or hang something from, you want a material with a high tensile strength. That's where you get into different alloys of steel and aluminum for different purposes.
Yeah! My dad is part of one of these (despite having a work shed in his back yard and literally owning a commercial production facility full of tools)
He mostly just goes there to tinker on stuff among other handy old dudes.
Need some stuff designed or printed? I can help with that.
What would be involved with getting a tube for a telescope made out of, say, aluminum? Something that sort of looks like this
I don't even own a telescope of my own yet, this is more of a theory thing. I have seen many posts while researching a telescope purchase about DIY scopes and I'm wondering how they do it
Basically, the idea is that you want your building to fail in an earthquake, but in a pre-determined spot. The reason is that failure dissipates energy. An earthquake is going to dump a certain amount of energy into your structure, and while your building acts elastically (i.e. pre-failure), all that energy does is just bounce around inside. The structural elements might be intact so far, but things like partition walls and HVAC (and the people inside!) are going to get knocked around and probably break. The only way this energy is going to disappear is through friction, and that can take many dozens of back-and-forth movements of the building, which can be bad news for your more brittle structural elements.
A structural fuse, on the other hand, eats energy quickly. Steel dissipates kinetic energy by heating up quite a bit when it yields. So, engineers on things like modern highrises and bridges (the new bay bridge being an excellent example) will add big plates of steel and design the structure such that those plates are guaranteed to undergo the most deformation, and therefore experience the most force, in the event of an earthquake. Once the danger is over, you can go in and unbolt the old, torn up plates and replace them with new ones~
I think we need a separate metallurgy thread so you can drop some knowledge on us.
My dad's done DIY scopes by both cannibalizing lesser scopes he thrifted and by using PVC pipes. I can ask him if he knows where to find a tube like you're talking about if you want. He's really into amateur astronomy.
yeah, I know
I'm in Seattle, there's a bunch of them
but I want one attached to my house, so I can just go noodle around in my spare time whenever I get a few minutes or take an entire weekend to just hammer away on a project
It wasn't! It was just less epic and more pulpy than the original Schwarzenegger one. My one friend who is as close to a Robert Howard scholar as you can get absolutely adored it, and it's a snappy flick with a lot of fun in it.
Plus the female lead punches out the female antagonist in an incredibly satisfying way.
Downside: The original Conan's soundtrack is one of the best ever and the new one was not even close.
Friction Stir Welding
Unlike traditional welding, which adds material, FSW just squishes the existing material together by softening it and swirling it around like you were stirring peanut butter in a jar
That is always the problem! It is so hard to separate the truth from fiction online at times. I have pretty much given up on reading anything written in English about medieval Japan because of this.
The video you linked seems pretty solid though. He seems logical and well reasoned, which instantly makes him better than 99% of the discourse online about historical arms and armor. I will end up watching more of his stuff, I think. Sometimes people like him or Lindy Biege (who he mentioned in that video) make conclusions that seem logical but often we are working with incomplete or biased data pools, so it is hard. Curious to see if he has any stuff about rapiers and if it gels with stuff I have learned from other sources. Of course, the thing with HEMA too is that even previously established interpretations of the manuals are revisited, questioned, revised, etc and sometimes what people thought turned out to be totally wrong. Which is part of what makes it exciting!
He references treatises constantly and mentions there are lots of interpretations
I fuckin love these sorts of threads.