I've got a few projects that could usefully start from aluminium castings. I
also currently have 120 ex-server hard disks.

When stripped of all the steel, copper, magnets and electronics the hard disks
yield 12oz-1lb of powder coated or cobalt sputtered aluminium. Probably in
three different alloys (case, platters and HP/Compaq mounting brackets)

The question is, does the team think that these will be a good source of
casting stock once they've been melted down, de-drossed and cast into ingots?

If they are a good source of stock I can get more disks, since it's in my
employer's interests to use me to dispose of all the server hard disks so that
we don't have to waste man-hours wiping them or destroying them when we scrap
servers.

Of course, anyone in their right mind would realize that it would be far more
efficient to buy a scrap auto engine or a pallet of ingots. But these disks
are free.

I am starting to run out of places to stick high-powered fridge magnets
though...


Any thoughts or experience out there?


Mark Rand
RTFM

Mark Rand wrote:
I've got a few projects that could usefully start from aluminium castings. I
also currently have 120 ex-server hard disks.

When stripped of all the steel, copper, magnets and electronics the hard disks
yield 12oz-1lb of powder coated or cobalt sputtered aluminium. Probably in
three different alloys (case, platters and HP/Compaq mounting brackets)

The question is, does the team think that these will be a good source of
casting stock once they've been melted down, de-drossed and cast into ingots?

I suspect that they might be made from "white metal"
rather than AL. Can't prove it, but trying to TIG
weld a couple WD castings together with AL filler gave
pretty sloppy results even with meticulous prep.

"Mark Rand" wrote in message
...
I've got a few projects that could usefully start from aluminium
castings. I
also currently have 120 ex-server hard disks.

When stripped of all the steel, copper, magnets and electronics the
hard disks
yield 12oz-1lb of powder coated or cobalt sputtered aluminium.
Probably in
three different alloys (case, platters and HP/Compaq mounting
brackets)

The question is, does the team think that these will be a good
source of
casting stock once they've been melted down, de-drossed and cast
into ingots?

If they are a good source of stock I can get more disks, since it's
in my
employer's interests to use me to dispose of all the server hard
disks so that
we don't have to waste man-hours wiping them or destroying them when
we scrap
servers.

Of course, anyone in their right mind would realize that it would be
far more
efficient to buy a scrap auto engine or a pallet of ingots. But
these disks
are free.

I am starting to run out of places to stick high-powered fridge
magnets
though...


Any thoughts or experience out there?


Mark Rand
RTFM

Mark,

The alloy will probably have been spec'ed originally for pressure die
casting rather than sand casting. I did a similar exercise with the
chassis from mainframe printers a few years back - lot of chunky
ingots piled up ready for use. Problem was that when I came to use
them they were a pain - couldn't get the metal to flow uniformly, and
when I ended up with a sound casting it was vile to machine (I was
making a replacement front bearing / mounting plate for a Bridgeport
pancake motor and was cnc machining it) - still using the motor but
that component is not a pretty example of machining !

A good source of decent alloy is pistons - track down an engine
rebuilder and be nice to him G

AWEM

Andrew Mawson wrote:
"Mark Rand" wrote in message
...
I've got a few projects that could usefully start from aluminium
castings. I also currently have 120 ex-server hard disks.

When stripped of all the steel, copper, magnets and electronics the
hard disks yield 12oz-1lb of powder coated or cobalt sputtered
aluminium. Probably in three different alloys (case, platters and
HP/Compaq mounting brackets)

The question is, does the team think that these will be a good
source of casting stock once they've been melted down, de-drossed
and cast into ingots?

If they are a good source of stock I can get more disks, since it's
in my employer's interests to use me to dispose of all the server
hard disks so that we don't have to waste man-hours wiping them or
destroying them when we scrap servers.

Of course, anyone in their right mind would realize that it would be
far more efficient to buy a scrap auto engine or a pallet of ingots.
But these disks are free.

I am starting to run out of places to stick high-powered fridge
magnets though...


Any thoughts or experience out there?


Mark Rand
RTFM

Mark,

The alloy will probably have been spec'ed originally for pressure die
casting rather than sand casting. I did a similar exercise with the
chassis from mainframe printers a few years back - lot of chunky
ingots piled up ready for use. Problem was that when I came to use
them they were a pain - couldn't get the metal to flow uniformly, and
when I ended up with a sound casting it was vile to machine (I was
making a replacement front bearing / mounting plate for a Bridgeport
pancake motor and was cnc machining it) - still using the motor but
that component is not a pretty example of machining !

A good source of decent alloy is pistons - track down an engine
rebuilder and be nice to him G

AWEM

There are several hobby casting groups on yahoo , I belong to the
"castinghobby" one . Those HDD cases are probably a ZA alloy , zinc and
aluminum , mostly zinc IIRC . Andrew is right about pistons , but also
consider extrusions (usually 6061) , wheels and cylinder heads are usually
A356 , and anything cast of aluminum is a candidate for the foundry .
--
Snag
But sell your cans
and buy tooling with
that money . Too much work
for too little metal .

Mark Rand wrote:
The question is, does the team think that these will be a good source of
casting stock once they've been melted down, de-drossed and cast into ingots?


I don't know about HDDs, but I'm told that car "alloy" wheels are good
stuff to use to remelt for castings.

Jordan

On Jun 19, 5:19*pm, Mark Rand wrote:
I've got a few projects that could usefully start from aluminium castings.. I
also currently have 120 ex-server hard disks.

When stripped of all the steel, copper, magnets and electronics the hard disks
yield 12oz-1lb of powder coated or cobalt sputtered aluminium. Probably in
three different alloys (case, platters and HP/Compaq mounting brackets)

The question is, does the team think that these will be a good source of
casting stock once they've been melted down, de-drossed and cast into ingots?

If they are a good source of stock I can get more disks, since it's in my
employer's interests to use me to dispose of all the server hard disks so that
we don't have to waste man-hours wiping them or destroying them when we scrap
servers.

Of course, anyone in their right mind would realize that it would be far more
efficient to buy a scrap auto engine or a pallet of ingots. But these disks
are free.

I am starting to run out of places to stick high-powered fridge magnets
though...

Any thoughts or experience out there?

Mark Rand
RTFM

Is your time free?

In my experience, the time it takes to strip hard drives down to their
basic castings is significant.

Or can you work for minimum wage at McDonalds and buy aluminum scrap
cheaper?

In the past I have stripped dozens of drives for their magnets...I
would have been better off time wise buying the magnets outright but I
did it while I did some house sitting for a family member.

If you do decide to strip drives, I would suggest trying to do this
type of busy work while watching television or surfing the Net so you
get something done productive. ;)

TMT

Google around to find specs for various aluminum alloys meant for
casting. You will see a WIDE range of characteristics. If you intend
to put your home made castings to any kind of functional use at all, I'd
advise against "mystery metal". You didn't even say whether the parts
you are scavenging ARE castings or not. Makes a HUGE difference!!!

Take the stuff you have to a scrap dealer and get what you can. Then go
buy pistons, if you want control. I know a guy who had been
demonstrating lost foam casting of aluminum for years. He uses pop
cans. But I don't think I'd cast B52 landing gear from them.

Learned about tensile strength of various aluminum casting alloys the
hard way,
Pete Stanaitis
-----------------

Mark Rand wrote:
I've got a few projects that could usefully start from aluminium castings. I
also currently have 120 ex-server hard disks.

When stripped of all the steel, copper, magnets and electronics the hard disks
yield 12oz-1lb of powder coated or cobalt sputtered aluminium. Probably in
three different alloys (case, platters and HP/Compaq mounting brackets)

The question is, does the team think that these will be a good source of
casting stock once they've been melted down, de-drossed and cast into ingots?

If they are a good source of stock I can get more disks, since it's in my
employer's interests to use me to dispose of all the server hard disks so that
we don't have to waste man-hours wiping them or destroying them when we scrap
servers.

Of course, anyone in their right mind would realize that it would be far more
efficient to buy a scrap auto engine or a pallet of ingots. But these disks
are free.

I am starting to run out of places to stick high-powered fridge magnets
though...


Any thoughts or experience out there?


Mark Rand
RTFM

On Fri, 19 Jun 2009 23:51:33 +0100, "Andrew Mawson"
wrote:


A good source of decent alloy is pistons - track down an engine
rebuilder and be nice to him G

AWEM

The bastiches scrapped out all of the spares from the 12 cylinder diesel
engine at work without telling me a few months back. Included were a couple of
pistons. The engine is 17 1/4" bore by 21" stroke, so you can imagine the
usefulness of the pistons :-(

I have the feeling that some silicon rich master alloy might help when I try
this out.


Mark Rand
RTFM

Mark Rand wrote:
I've got a few projects that could usefully start from aluminium castings. I
also currently have 120 ex-server hard disks.

When stripped of all the steel, copper, magnets and electronics the hard disks
yield 12oz-1lb of powder coated or cobalt sputtered aluminium. Probably in
three different alloys (case, platters and HP/Compaq mounting brackets)

The question is, does the team think that these will be a good source of
casting stock once they've been melted down, de-drossed and cast into ingots?

The cases make great casting aluminum that also
machines very well.

The platters may be more exotic stuff, but did you
know most of the dull silvery-colored ones are
plated with pure platinum? There are some web
sites that have simple systems for peeling the
platinum off.

Jon

Andrew Mawson wrote:
"Mark Rand" wrote in message
...

I've got a few projects that could usefully start from aluminium

castings. I

also currently have 120 ex-server hard disks.

When stripped of all the steel, copper, magnets and electronics the

hard disks

yield 12oz-1lb of powder coated or cobalt sputtered aluminium.

Probably in

three different alloys (case, platters and HP/Compaq mounting

brackets)

The question is, does the team think that these will be a good

source of

casting stock once they've been melted down, de-drossed and cast

into ingots?

If they are a good source of stock I can get more disks, since it's

in my

employer's interests to use me to dispose of all the server hard

disks so that

we don't have to waste man-hours wiping them or destroying them when

we scrap

servers.

Of course, anyone in their right mind would realize that it would be

far more

efficient to buy a scrap auto engine or a pallet of ingots. But

these disks

are free.

I am starting to run out of places to stick high-powered fridge

magnets

though...


Any thoughts or experience out there?


Mark Rand
RTFM


Mark,

The alloy will probably have been spec'ed originally for pressure die
casting rather than sand casting. I did a similar exercise with the
chassis from mainframe printers a few years back - lot of chunky
ingots piled up ready for use. Problem was that when I came to use
them they were a pain - couldn't get the metal to flow uniformly, and
when I ended up with a sound casting it was vile to machine (I was
making a replacement front bearing / mounting plate for a Bridgeport
pancake motor and was cnc machining it) - still using the motor but
that component is not a pretty example of machining !


Even an alloy intended for sand casting can be horrid to machine when
used in the as cast condition due to it being soft and gummy. A company
a mate used to work for always had their aluminium sand castings heat
treated for machinability reasons.

A good source of decent alloy is pistons - track down an engine
rebuilder and be nice to him G

AWEM

"David Billington" wrote in message
...
Andrew Mawson wrote:
"Mark Rand" wrote in message
...

I've got a few projects that could usefully start from aluminium

castings. I

also currently have 120 ex-server hard disks.

When stripped of all the steel, copper, magnets and electronics
the

hard disks

yield 12oz-1lb of powder coated or cobalt sputtered aluminium.

Probably in

three different alloys (case, platters and HP/Compaq mounting

brackets)

The question is, does the team think that these will be a good

source of

casting stock once they've been melted down, de-drossed and cast

into ingots?

If they are a good source of stock I can get more disks, since
it's

in my

employer's interests to use me to dispose of all the server hard

disks so that

we don't have to waste man-hours wiping them or destroying them
when

we scrap

servers.

Of course, anyone in their right mind would realize that it would
be

far more

efficient to buy a scrap auto engine or a pallet of ingots. But

these disks

are free.

I am starting to run out of places to stick high-powered fridge

magnets

though...


Any thoughts or experience out there?


Mark Rand
RTFM


Mark,

The alloy will probably have been spec'ed originally for pressure
die
casting rather than sand casting. I did a similar exercise with
the
chassis from mainframe printers a few years back - lot of chunky
ingots piled up ready for use. Problem was that when I came to use
them they were a pain - couldn't get the metal to flow uniformly,
and
when I ended up with a sound casting it was vile to machine (I was
making a replacement front bearing / mounting plate for a
Bridgeport
pancake motor and was cnc machining it) - still using the motor
but
that component is not a pretty example of machining !


Even an alloy intended for sand casting can be horrid to machine
when
used in the as cast condition due to it being soft and gummy. A
company
a mate used to work for always had their aluminium sand castings
heat
treated for machinability reasons.

A good source of decent alloy is pistons - track down an engine
rebuilder and be nice to him G

AWEM



Solution treatment is the term to Google for - see the third paragraph
down this page:

http://www.azom.com/Details.asp?ArticleID=2540

AWEM

Jordan wrote:
Mark Rand wrote:
The question is, does the team think that these will be a good source of
casting stock once they've been melted down, de-drossed and cast into
ingots?


I don't know about HDDs, but I'm told that car "alloy" wheels are good
stuff to use to remelt for castings.

Jordan

I use mostly Cummins Diesel pistons--they are a very strong alloy that
can be heat-treated after casting and get great strength and xlnt
machining qualities.--ps-they have a steel/cast iron piston ring insert
that has to be fished out as they melt.

Also, if you can afford an I.R. Temp measuring gun,, that's great--you
can cull out any zinc/Al mixture by the melt point..the cheaper ones
don't go high enough to measure the M.P. of Al, Jerry

Find out the asking price for alum scrap at the salvage yards--then find
a heavyduty engine rebuilder & offer him a little more than that,

On Sat, 20 Jun 2009 14:21:27 +0100, "Andrew Mawson"
wrote:


Solution treatment is the term to Google for - see the third paragraph
down this page:

http://www.azom.com/Details.asp?ArticleID=2540

AWEM

We seem to have varying views on the machinability of the alloys involved. One
datum is that they obviously machine beautifully the first time around, so I'm
hopeful that it'll be better than extruded rubbish.


I'd already boned up on Solution heat treatment and precipitation hardening.

It's be nice it I could convince the lads in the metallurgy lab at work to do
a full assay of the composition of a sample ingot. Trouble is, most of their
work got sent to China, so they've lost the will to live...

It would be possible to slice an ingot into coupons and then try solution heat
treating different coupons at different temperatures until the correct
temperature was discovered. If the batch of metal were consistent enough, that
would only need to be done once every 50-100lb of metal, which wouldn't be too
bad. That's probably what I'll try. Of course that means building a decent,
controllable, heat treating oven. Still, that'll come in useful for and
aluminium casting work, whatever the source of metal.

It takes 10-15 minutes to strip down a drive whilst watching the television
news. The concentration helps to stop me shouting at the news presenters when
they get stupid ;-)


Mark Rand
RTFM

Mark Rand wrote in
:

I've got a few projects that could usefully start from aluminium
castings. I also currently have 120 ex-server hard disks.

When stripped of all the steel, copper, magnets and electronics the
hard disks yield 12oz-1lb of powder coated or cobalt sputtered
aluminium. Probably in three different alloys (case, platters and
HP/Compaq mounting brackets)


I suggest you melt like component parts separately and ingot them before
using. Label the ingots with the source of the feed stock so you know what
made nice stuff and more importantly what is crap that needs blending to be
more usefull. Gummy machining material (usually wrought alloys) can be
helped a bit with a few percent of copper. Add some small cross section
copper like 14ga. wire pieces after the aluminum is fully melted. Pig off
as ingots, test machine and then remelt for your project.

"Mark Rand" wrote in message
...
On Sat, 20 Jun 2009 14:21:27 +0100, "Andrew Mawson"
wrote:


Solution treatment is the term to Google for - see the third
paragraph
down this page:

http://www.azom.com/Details.asp?ArticleID=2540

AWEM

We seem to have varying views on the machinability of the alloys
involved. One
datum is that they obviously machine beautifully the first time
around, so I'm
hopeful that it'll be better than extruded rubbish.


I'd already boned up on Solution heat treatment and precipitation
hardening.

It's be nice it I could convince the lads in the metallurgy lab at
work to do
a full assay of the composition of a sample ingot. Trouble is, most
of their
work got sent to China, so they've lost the will to live...

It would be possible to slice an ingot into coupons and then try
solution heat
treating different coupons at different temperatures until the
correct
temperature was discovered. If the batch of metal were consistent
enough, that
would only need to be done once every 50-100lb of metal, which
wouldn't be too
bad. That's probably what I'll try. Of course that means building a
decent,
controllable, heat treating oven. Still, that'll come in useful for
and
aluminium casting work, whatever the source of metal.

It takes 10-15 minutes to strip down a drive whilst watching the
television
news. The concentration helps to stop me shouting at the news
presenters when
they get stupid ;-)


Mark Rand
RTFM


Mark,

I have an alloy analyser - draws a carbon arc off the sample, scans
it, and reports on composition and prints it out. As the foundry
building isn't quite finished yet (but it does have walls, roof and
doors!) the analyser is still packed up from the move, but when it
comes out blinking to the daylight post me a sample and I'll run it
for you.

Andrew

Andrew Mawson wrote:
"Mark Rand" wrote in message
...

On Sat, 20 Jun 2009 14:21:27 +0100, "Andrew Mawson"
wrote:



Solution treatment is the term to Google for - see the third

paragraph

down this page:

http://www.azom.com/Details.asp?ArticleID=2540

AWEM

We seem to have varying views on the machinability of the alloys

involved. One

datum is that they obviously machine beautifully the first time

around, so I'm

hopeful that it'll be better than extruded rubbish.


I'd already boned up on Solution heat treatment and precipitation

hardening.

It's be nice it I could convince the lads in the metallurgy lab at

work to do

a full assay of the composition of a sample ingot. Trouble is, most

of their

work got sent to China, so they've lost the will to live...

It would be possible to slice an ingot into coupons and then try

solution heat

treating different coupons at different temperatures until the

correct

temperature was discovered. If the batch of metal were consistent

enough, that

would only need to be done once every 50-100lb of metal, which

wouldn't be too

bad. That's probably what I'll try. Of course that means building a

decent,

controllable, heat treating oven. Still, that'll come in useful for

and

aluminium casting work, whatever the source of metal.

It takes 10-15 minutes to strip down a drive whilst watching the

television

news. The concentration helps to stop me shouting at the news

presenters when

they get stupid ;-)


Mark Rand
RTFM



Mark,

I have an alloy analyser - draws a carbon arc off the sample, scans
it, and reports on composition and prints it out. As the foundry
building isn't quite finished yet (but it does have walls, roof and
doors!) the analyser is still packed up from the move, but when it
comes out blinking to the daylight post me a sample and I'll run it
for you.

Andrew


An optical emission spectrometer by the sound of it, something I have
some knowledge of, having programmed software for them for the last 16
years or so. The one I work with uses a tungsten arc like TIG but the
principle is the same.

"Jon Elson" wrote in message
...
Mark Rand wrote:
I've got a few projects that could usefully start from aluminium
castings. I
also currently have 120 ex-server hard disks.

When stripped of all the steel, copper, magnets and electronics the hard
disks
yield 12oz-1lb of powder coated or cobalt sputtered aluminium. Probably
in
three different alloys (case, platters and HP/Compaq mounting brackets)

The question is, does the team think that these will be a good source of
casting stock once they've been melted down, de-drossed and cast into
ingots?

The cases make great casting aluminum that also machines very well.

The platters may be more exotic stuff, but did you know most of the dull
silvery-colored ones are plated with pure platinum? There are some web
sites that have simple systems for peeling the platinum off.

Jon

Had you been following the gold forum, you'd know that that is not the case.
Discs with platinum are not commonly found. For the most part, everyone
has abandoned the idea of recovering platinum from them.

Harold

Harold and Susan Vordos wrote:


Had you been following the gold forum, you'd know that that is not the case.
Discs with platinum are not commonly found. For the most part, everyone
has abandoned the idea of recovering platinum from them.

Whoops, sorry, I **AM** out of touch! The gold
salvage work I have done has been a complete
sideline when things are real slow otherwise, so I
poke in on your great forum maybe a couple times a
year. I have some platters from Seagate Sabre V
drives from 1990 that I think MAY be the platinum
jobs. I scrapped those primarily for the
incredible amount of good casting aluminum in the
housings.

I'm sure the home PC-class of drives don't have
any platinum in them.

Thanks again for your great contributions to the
gold forum, I'm sure I will get back to it again,
as I still have a lot of gold-plated junk around
here that needs a reduction
in volume. I HAVE gotten a Troy Oz out so far and
have barely started in on it.

Jon

"Jon Elson" wrote in message
...
snip-

I still have a lot of gold-plated junk around here that needs a reduction
in volume. I HAVE gotten a Troy Oz out so far and have barely started in
on it.

Jon

Well done, Jon. It's really rewarding to recover from low grade materials,
where the values are often not recognizable. Not the case with your
stuff, but it still feels good!

Keep on keepin' on---

Harold

Mark Rand wrote:

I've got a few projects that could usefully start from aluminium castings. I
also currently have 120 ex-server hard disks.

When stripped of all the steel, copper, magnets and electronics the hard disks
yield 12oz-1lb of powder coated or cobalt sputtered aluminium. Probably in
three different alloys (case, platters and HP/Compaq mounting brackets)

The question is, does the team think that these will be a good source of
casting stock once they've been melted down, de-drossed and cast into ingots?

If they are a good source of stock I can get more disks, since it's in my
employer's interests to use me to dispose of all the server hard disks so that
we don't have to waste man-hours wiping them or destroying them when we scrap
servers.

Of course, anyone in their right mind would realize that it would be far more
efficient to buy a scrap auto engine or a pallet of ingots. But these disks
are free.

I am starting to run out of places to stick high-powered fridge magnets
though...

Try dropping one of those magnets through a length of copper water pipe.

Watch how the induced current in the copper creates an opposing magnetic
field slowing down the magnet's decent. Works best with a cylindrical
magnet a little smaller than the inside diameter of the pipe, it'll just
ooze down through the pipe.

Jeff

--
Jeffry Wisnia
(W1BSV + Brass Rat '57 EE)
The speed of light is 1.8*1012 furlongs per fortnight.



Any thoughts or experience out there?


Mark Rand
RTFM

On Tue, 23 Jun 2009 15:39:49 -0400, jeff_wisnia
wrote:

Mark Rand wrote:

I've got a few projects that could usefully start from aluminium castings. I
also currently have 120 ex-server hard disks.

When stripped of all the steel, copper, magnets and electronics the hard disks
yield 12oz-1lb of powder coated or cobalt sputtered aluminium. Probably in
three different alloys (case, platters and HP/Compaq mounting brackets)

The question is, does the team think that these will be a good source of
casting stock once they've been melted down, de-drossed and cast into ingots?

If they are a good source of stock I can get more disks, since it's in my
employer's interests to use me to dispose of all the server hard disks so that
we don't have to waste man-hours wiping them or destroying them when we scrap
servers.

Of course, anyone in their right mind would realize that it would be far more
efficient to buy a scrap auto engine or a pallet of ingots. But these disks
are free.

I am starting to run out of places to stick high-powered fridge magnets
though...

I use the added weight to direct the reflector on the industrial,
chain mounted 4' fluorescent unit over my SB"A"

Try dropping one of those magnets through a length of copper water pipe.

Watch how the induced current in the copper creates an opposing magnetic
field slowing down the magnet's decent. Works best with a cylindrical
magnet a little smaller than the inside diameter of the pipe, it'll just
ooze down through the pipe.

Jeff
I have a 1/4" dia.x 1" magnet inside a length of 3/8" copper tube
clinging to the front of the file cabinet ready for the next
"uninitiated person".
Gerry :-)}
London, Canada

On Tue, 23 Jun 2009 15:39:49 -0400, jeff_wisnia
wrote:

Mark Rand wrote:

I've got a few projects that could usefully start from aluminium castings. I
also currently have 120 ex-server hard disks.

When stripped of all the steel, copper, magnets and electronics the hard disks
yield 12oz-1lb of powder coated or cobalt sputtered aluminium. Probably in
three different alloys (case, platters and HP/Compaq mounting brackets)

The question is, does the team think that these will be a good source of
casting stock once they've been melted down, de-drossed and cast into ingots?

If they are a good source of stock I can get more disks, since it's in my
employer's interests to use me to dispose of all the server hard disks so that
we don't have to waste man-hours wiping them or destroying them when we scrap
servers.

Of course, anyone in their right mind would realize that it would be far more
efficient to buy a scrap auto engine or a pallet of ingots. But these disks
are free.

I am starting to run out of places to stick high-powered fridge magnets
though...

The enclosures are probably worth messing with and are probably a
ZAMAC die-cast alloy of some sort. It has to be really stable stuff,
a hard drive warping as it ages would not be a good thing...

But you would want to know what the alloy is before putting any
effort into it - might want to beg or borrow one of the scrapyard
spectrometer guns mentioned elsewhere in this thread IIRC.

And every time you melt it, the composition and properties of the
metal changes as some of the admixture elements boil out of the pot.

It might work okay if you melt and flux the hard drive cases and
pour directly into the flask for the project - but adding another melt
by turning it into ingots as an intermediary step is just gonna throw
the metal that much more out of whack. Likely to be the difference
between success and disaster.

Besides, you have to know what's in the metal if you want to sell
the end product in a country where the RoHS Weenies have taken over.

Try dropping one of those magnets through a length of copper water pipe.

Watch how the induced current in the copper creates an opposing magnetic
field slowing down the magnet's decent. Works best with a cylindrical
magnet a little smaller than the inside diameter of the pipe, it'll just
ooze down through the pipe.

Jeff

Jeffry Wisnia
(W1BSV + Brass Rat '57 EE)
The speed of light is 1.8*1012 furlongs per fortnight.

Isn't that supposed to be 1.8*10E12 ? 10 to the 12th power? I am
by no means a calculus wonk, but I seem to recall it that way...

-- Bruce --

"Bruce L. Bergman" wrote in message
...
On Tue, 23 Jun 2009 15:39:49 -0400, jeff_wisnia
wrote:

Mark Rand wrote:

I've got a few projects that could usefully start from aluminium
castings. I
also currently have 120 ex-server hard disks.

When stripped of all the steel, copper, magnets and electronics the hard
disks
yield 12oz-1lb of powder coated or cobalt sputtered aluminium. Probably
in
three different alloys (case, platters and HP/Compaq mounting brackets)

The question is, does the team think that these will be a good source of
casting stock once they've been melted down, de-drossed and cast into
ingots?

If they are a good source of stock I can get more disks, since it's in
my
employer's interests to use me to dispose of all the server hard disks
so that
we don't have to waste man-hours wiping them or destroying them when we
scrap
servers.

Of course, anyone in their right mind would realize that it would be far
more
efficient to buy a scrap auto engine or a pallet of ingots. But these
disks
are free.

I am starting to run out of places to stick high-powered fridge magnets
though...

The enclosures are probably worth messing with and are probably a
ZAMAC die-cast alloy of some sort. It has to be really stable stuff,
a hard drive warping as it ages would not be a good thing...

FWIW, Zamac is hardly stable. It's strong -- much stronger than most people
would imagine -- and it's reasonably stiff, but it has a strong tendency to
creep at even fairly low temperatures, like most zinc alloys.

Through a combination of structural design and section thicknesses, they may
have completely overcome the problem in the application you're talking
about. But Zamac, for the record, is much more prone to creep than aluminum
is, for example.

--
Ed Huntress

Bruce L. Bergman wrote:
On Tue, 23 Jun 2009 15:39:49 -0400, jeff_wisnia
wrote:


Mark Rand wrote:


I've got a few projects that could usefully start from aluminium castings. I
also currently have 120 ex-server hard disks.

When stripped of all the steel, copper, magnets and electronics the hard disks
yield 12oz-1lb of powder coated or cobalt sputtered aluminium. Probably in
three different alloys (case, platters and HP/Compaq mounting brackets)

The question is, does the team think that these will be a good source of
casting stock once they've been melted down, de-drossed and cast into ingots?

If they are a good source of stock I can get more disks, since it's in my
employer's interests to use me to dispose of all the server hard disks so that
we don't have to waste man-hours wiping them or destroying them when we scrap
servers.

Of course, anyone in their right mind would realize that it would be far more
efficient to buy a scrap auto engine or a pallet of ingots. But these disks
are free.

I am starting to run out of places to stick high-powered fridge magnets
though...


The enclosures are probably worth messing with and are probably a
ZAMAC die-cast alloy of some sort. It has to be really stable stuff,
a hard drive warping as it ages would not be a good thing...

But you would want to know what the alloy is before putting any
effort into it - might want to beg or borrow one of the scrapyard
spectrometer guns mentioned elsewhere in this thread IIRC.

And every time you melt it, the composition and properties of the
metal changes as some of the admixture elements boil out of the pot.

It might work okay if you melt and flux the hard drive cases and
pour directly into the flask for the project - but adding another melt
by turning it into ingots as an intermediary step is just gonna throw
the metal that much more out of whack. Likely to be the difference
between success and disaster.

Besides, you have to know what's in the metal if you want to sell
the end product in a country where the RoHS Weenies have taken over.


Try dropping one of those magnets through a length of copper water pipe.

Watch how the induced current in the copper creates an opposing magnetic
field slowing down the magnet's decent. Works best with a cylindrical
magnet a little smaller than the inside diameter of the pipe, it'll just
ooze down through the pipe.

Jeff

Jeffry Wisnia
(W1BSV + Brass Rat '57 EE)
The speed of light is 1.8*1012 furlongs per fortnight.


Isn't that supposed to be 1.8*10E12 ? 10 to the 12th power? I am
by no means a calculus wonk, but I seem to recall it that way...

-- Bruce --


Yes it is....My sig has a caret (like a small inverted vee.) in between
the 10 and the 12, but I bet some fonts don't reproduce that symbol.

So, I'll be changing it to an "E".

Thanks,

Jeff

--
Jeffry Wisnia
(W1BSV + Brass Rat '57 EE)
The speed of light is 1.8*10^12 furlongs per fortnight.

(The above sig still has the caret in it.)