Scavenging for Aluminum: a motherboard motherlode
Our Fire Craft group here is still hanging out around the dawn of the Age of Aluminum, has been for a long time now. We took a little break for various reasons, but we're still on the lookout for aluminum to melt, when it finally comes time for casting. Mainly we've been collecting pop cans, but twice now I've come across an abandoned desktop computer, and these are a great source.
Look inside! What fun! So many colours and diodes and doodads and thingamabobs. And in fact, they all do something!
Somehow all of this stuff makes it possible to, for example, type this text, and make this blogpost, and have Stravinsky come on in shuffle-mode while I do it (right now, Ebony Concerto written for Woody Herman and Band), and upload some photos to show you the motherboard, and give you a link to to the Ebony Concerto, and store more information than I know what to do with.
Am I amazed by all of this because I am so ignorant of how it works? Or am I amazed because I actually know enough to be amazed?
Think about it for a second. At the heart of a computer (or cellphone) lies a silicon chip.
And what is silicon? Basically, sand! (Sand is most commonly made of silica, aka silicon dioxide.) At first I thought it'd be a bit strange to write a post all about the innards of a computer, but it seems we're never far away from the Fire Craft, because no matter where we go, we end up meeting sand or clay or glass (silica) or copper, or in this case...
...the third most abundant element on Earth (after oxygen and silicon).
So here's what I discovered about this desktop in my quest to get at the metal motherlode within.
A computer generally consists of a CPU, memory, and some means for input and output. The input and output devices are connected to the CPU and memory by a system called a bus (from the Latin, omnibus, 'for all', just like the one you ride to work), which is essentially a collection of wires that create circuits that ferry information around. A 32-bit computer has 32 wires on its data bus, and a 64-bit has, you guessed it, 64. (I tried counting them but got confused at 67, so it's not so simple.)
"Information" is a specific term in this case, always coming in the form of 1s and 0s. Information became quantifiable in this way back in 1948, in a world-changing leap by a young guy named Claude Shannon, who was given lots of time to explore and trip out on ideas while working at Bell Labs. Back then, he called the minimal unit of information a "bit".
All of the above is already astounding enough, and should give anyone who isn't a computer engineer enough to marvel at for some time. But let's go on, because we're after aluminum...
Now, the CPU of this computer is an Intel Core2 Duo Processor E8000 (circled below). The way they make these chips is probably the most astonishing part of this whole story.
A chip is a small silicon plate filled with millions of itsy-bitsy, teeny-weeny transistors, resistors, and diodes, which all together form an Integrated Circuit. A large amount of chips are made at once on a silicon wafer, built up through various steps--a process that can take weeks--and then later they are sliced up with one helluva fine saw. The process involves, in part and in brief, UV light shone through a mask to transfer the circuit structure onto the wafer; atoms being shot onto specific areas of the silicon coating (ion implantation) to modify its electrical properties in different places, i.e. creating areas of conduction or resistance; and eventually, a vacuum-deposited microscopic layer of aluminum (or copper) to interconnect the millions of microscopic transistors built onto the chip.
If you want a lot more detail, watch how chips are made.
Okay, but where's the aluminum? In the heat sink!
A heat sink is a lovely piece of metal that absorbs heat from the surroundings and then disperses it into the air, and with the help of a fan, out of your device. Whenever you have electricity flowing, you're going to have some resistance, and as the resistance builds up, it creates heat. Ever used your cellphone intensely and felt it heat up? There you go. Too much heat can be very damaging to all those micro-components.
You'll find the main heat sink (the beautiful one with all the fins) right over top of the CPU, with a big fan sitting right on top of it, as pictured here:
In fact, in that photo you'll see two heat sinks: the active one, with the fan, and a passive one beside it. There were three in total, though. In the photo below I've flipped the main active one over so you can see it; then to its right and in the middle of the board, a passive one that sits over a chip called the Northbridge (memory controller hub) which is directly connected to the CPU; and at the bottom left, the third heat sink that sits over the Southbridge chip (input/output hub).
In the power supply for the computer, there were two more heat sinks:
These had a transistors connected to them, which were easily detached.
Aluminium: 99.5% min (ed: yeah!)
Copper: 0.05% max
Iron: 0.4% max
Magnesium: 0.05% max
Manganese: 0.05% max
Silicon: 0.25% max
Titanium: 0.03% max
Vanadium: 0.05% max
Zinc: 0.05% max
You might also see copper used as a heat sink - another desktop I took apart used it. It's much better at dispersing heat, but more dense and more expensive than aluminium, so not as common.
And there you go. If you'd like some very simple info on how a computer works, this set of videos does a good, simple job. Plus it's introduced by Bill Gates doing his best to channel Mr. Rogers.
All in all, we got 520 grams of nearly pure aluminum out of one thrown-away desktop! And in the process, we learned a whole bunch about just how far lowly sand has taken us.
Look inside! What fun! So many colours and diodes and doodads and thingamabobs. And in fact, they all do something!
Somehow all of this stuff makes it possible to, for example, type this text, and make this blogpost, and have Stravinsky come on in shuffle-mode while I do it (right now, Ebony Concerto written for Woody Herman and Band), and upload some photos to show you the motherboard, and give you a link to to the Ebony Concerto, and store more information than I know what to do with.
 |
| Hypnotizing, no? |
Am I amazed by all of this because I am so ignorant of how it works? Or am I amazed because I actually know enough to be amazed?
Think about it for a second. At the heart of a computer (or cellphone) lies a silicon chip.
And what is silicon? Basically, sand! (Sand is most commonly made of silica, aka silicon dioxide.) At first I thought it'd be a bit strange to write a post all about the innards of a computer, but it seems we're never far away from the Fire Craft, because no matter where we go, we end up meeting sand or clay or glass (silica) or copper, or in this case...
Aluminum!
So here's what I discovered about this desktop in my quest to get at the metal motherlode within.
A computer generally consists of a CPU, memory, and some means for input and output. The input and output devices are connected to the CPU and memory by a system called a bus (from the Latin, omnibus, 'for all', just like the one you ride to work), which is essentially a collection of wires that create circuits that ferry information around. A 32-bit computer has 32 wires on its data bus, and a 64-bit has, you guessed it, 64. (I tried counting them but got confused at 67, so it's not so simple.)
 |
| Some of the connections that make up the bus are visible here. The squiggly ones are like that because in some circuits, a signal has to arrive at different points at the same time. Now, because some of those points are physically closer than others, they are made more squiggly, thus lengthening the amount of time it takes for the impulse to arrive. But we're talking nanoseconds! |
"Information" is a specific term in this case, always coming in the form of 1s and 0s. Information became quantifiable in this way back in 1948, in a world-changing leap by a young guy named Claude Shannon, who was given lots of time to explore and trip out on ideas while working at Bell Labs. Back then, he called the minimal unit of information a "bit".
All of the above is already astounding enough, and should give anyone who isn't a computer engineer enough to marvel at for some time. But let's go on, because we're after aluminum...
If you want a lot more detail, watch how chips are made.
Okay, but where's the aluminum? In the heat sink!
A heat sink is a lovely piece of metal that absorbs heat from the surroundings and then disperses it into the air, and with the help of a fan, out of your device. Whenever you have electricity flowing, you're going to have some resistance, and as the resistance builds up, it creates heat. Ever used your cellphone intensely and felt it heat up? There you go. Too much heat can be very damaging to all those micro-components.
You'll find the main heat sink (the beautiful one with all the fins) right over top of the CPU, with a big fan sitting right on top of it, as pictured here:
In fact, in that photo you'll see two heat sinks: the active one, with the fan, and a passive one beside it. There were three in total, though. In the photo below I've flipped the main active one over so you can see it; then to its right and in the middle of the board, a passive one that sits over a chip called the Northbridge (memory controller hub) which is directly connected to the CPU; and at the bottom left, the third heat sink that sits over the Southbridge chip (input/output hub).
In the power supply for the computer, there were two more heat sinks:
These had a transistors connected to them, which were easily detached.
The most common heat sink materials are aluminium alloys, and specifically, "1050 alloy", which according to Wikipedia, "has one of the higher thermal conductivity values at 229 W per meter/Kelvin." The alloy composition of 1050 aluminium is:
Aluminium: 99.5% min (ed: yeah!)
Copper: 0.05% max
Iron: 0.4% max
Magnesium: 0.05% max
Manganese: 0.05% max
Silicon: 0.25% max
Titanium: 0.03% max
Vanadium: 0.05% max
Zinc: 0.05% max
You might also see copper used as a heat sink - another desktop I took apart used it. It's much better at dispersing heat, but more dense and more expensive than aluminium, so not as common.
And there you go. If you'd like some very simple info on how a computer works, this set of videos does a good, simple job. Plus it's introduced by Bill Gates doing his best to channel Mr. Rogers.
All in all, we got 520 grams of nearly pure aluminum out of one thrown-away desktop! And in the process, we learned a whole bunch about just how far lowly sand has taken us.
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