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Tuckerfan
08-12-2006, 04:45 AM
What's a cubic foot of steel chips weigh (small chips, not the long, stringy ones)?

Going price for scrap steel per pound?

At what temp aluminum ignites?

The best way to machine magnesium?

(No, I don't know the answers to these, but I've got projects I'm working on that I need the info for.)

Elninio
08-12-2006, 05:56 AM
What's a cubic foot of steel chips weigh (small chips, not the long, stringy ones)?

Going price for scrap steel per pound?

At what temp aluminum ignites?

The best way to machine magnesium?

(No, I don't know the answers to these, but I've got projects I'm working on that I need the info for.)

you cant measure it in cubic feet , depends how much the chips are compressed, so the question is, how much per pound or kg. Also by ignite do you mean melt? aluminum doesnt change color to a red like steel and brass do when it is heated. Also a while ago there was a post about someone who wanted to melt magnesium and someone replied by saying that it was almost impossible to see because it turns very bright, so if u were to machine it, make sure its kept cool

Tuckerfan
08-12-2006, 06:23 AM
I'm looking for a ballpark figure on the weight of steel. I'm currently a screw machine operator, and management can't seem to figure out the need to empty the chips in the oil tank, so I'm hoping that if I point out that it's money sitting down there, they'll clean the things out. It's getting real old having to unclog the pumps on the things every day. (It's probably been a decade or so since the machines have been completely cleaned. It could be longer, however, as most of the machines date from the 1930s.)

And I do mean the ignition point of aluminum. I used to work in a foundry, so I know all about the melting point, but I want the stuff to catch fire (which it does if it gets hot enough).

As for the magnesium, I know to keep it cool (we used to play with the stuff in chemistry class in high school, and we tried to melt it out the foundry I worked at [strangely, I was the only one there who knew the stuff burns, and that when it catches fire, there's a whole lotta nuttin' you can do about it]), but I'd like to know the best way to do that. Should I machine it fast or slow? What type of cutter to use in the mill, etc., etc., etc.

Doc Nickel
08-12-2006, 06:26 AM
1) What's the density? I seem to recall sintered material (densely pressed) is typically around 95 to 98% "solid", so a bucket of loose chips is probably far less than that. Maybe anywhere from 40% to 60% density? Ballpark figure, then, of 50% the weight of a cube of solid steel, or roughly 250 pounds.

Plus or minus 20%. Depends on the size of the chip and how tightly they're tamped.

2) Depends on your location. I've heard as high as $120 a ton for well segregated "clean" steel, but up here in Alaska, it's almost worthless. I think the recycler gives maybe $20 a car, crushed. Home-shop sized batches aren't worth the gas it took to haul it there.

3) What kind of aluminum? Finely-powdered aluminum is used in Thermite and the Shuttle's solid-rocket boosters, and can sometimes be (accidentally) ignited by a mere grinding spark. Larger whole chunks will melt long before igniting, and probably will pass the boiling point before doing so.

4) Sharp tools and under coolant. Make chips and ribbons rather than thin flakes and dust, keep the chip tray clean and clear of oil or other fuels. Keep the workpiece cool.

Doc.

Tuckerfan
08-12-2006, 06:50 AM
1) What's the density? I seem to recall sintered material (densely pressed) is typically around 95 to 98% "solid", so a bucket of loose chips is probably far less than that. Maybe anywhere from 40% to 60% density? Ballpark figure, then, of 50% the weight of a cube of solid steel, or roughly 250 pounds.

Plus or minus 20%. Depends on the size of the chip and how tightly they're tamped.
Based on your figures, some rough calculations of how big the tanks are, I'd say we're looking at about 360 tons of chips in all the machines. (If anyone wants to check my math, the tanks are about 3 1/2 ft wide, 7 1/2 feet long, 15 inches high, and there's about 9 inches of chips in the bottom. We've got about 30 machines, ranging from 1 inch to 3 inch, and my calcs are based on the tank sizes for the 1 inch machines, and I figured in only 10 machines.)

2) Depends on your location. I've heard as high as $120 a ton for well segregated "clean" steel, but up here in Alaska, it's almost worthless. I think the recycler gives maybe $20 a car, crushed. Home-shop sized batches aren't worth the gas it took to haul it there.Well, it's certainly not clean steel. It's mixed with monel, brass, and aluminum, so figuring $10/ton, that's $3,600. Hmm. May have to whip out the Enron pencil for my figures before I show them to the boss. :D


3) What kind of aluminum? Finely-powdered aluminum is used in Thermite and the Shuttle's solid-rocket boosters, and can sometimes be (accidentally) ignited by a mere grinding spark. Larger whole chunks will melt long before igniting, and probably will pass the boiling point before doing so.Light gauge wire, or cut up strips from an aluminum can.


4) Sharp tools and under coolant. Make chips and ribbons rather than thin flakes and dust, keep the chip tray clean and clear of oil or other fuels. Keep the workpiece cool.

Doc.Hmmm. Could be tricky. I don't think that any of the mills at work have coolant set ups installed, and since I'll be doing this on the sly, I can't easily rig something up. Might have to shelve that idea for awhile.

Doc Nickel
08-12-2006, 07:29 AM
1) Problem is, it's all soaked in oil. It'll have to be "washed" before it's recycled, or at least set out to drain for a good long while first.

2) That's even worse. Mixed scrap like that is worth even less, since it'll cost more to seperate it.

By the time you combine the two (oily and mixed) you'll be lucky if you don't have to pay to get rid of it- which is probably why it's still in the tanks.

3) Chunks, even can strips and wire, probably won't ignite easily, they'll need a fuel or oxidizer. It'd gotta be pretty finely powdered before it's "easy" to light.

4) Oil can be used as coolant, though you'll have to confirm that with some of our more seasoned members. I've welded way more magnesium than I've machined. Magnesium is tough to "light" unless you have fine flakes or powder, so as long as your machining process makes chips and not flakes, you'll probably be okay.

However, sneaking in a semi-hazardous material without the boss knowing might be a bit on the iffy side. :)

Doc.

Tuckerfan
08-12-2006, 07:54 AM
1) Problem is, it's all soaked in oil. It'll have to be "washed" before it's recycled, or at least set out to drain for a good long while first.We've got a chip spinner to seperate the oil out.


2) That's even worse. Mixed scrap like that is worth even less, since it'll cost more to seperate it.

By the time you combine the two (oily and mixed) you'll be lucky if you don't have to pay to get rid of it- which is probably why it's still in the tanks.Okay, so I'll definately be using the Enron pencil then.


3) Chunks, even can strips and wire, probably won't ignite easily, they'll need a fuel or oxidizer. It'd gotta be pretty finely powdered before it's "easy" to light.Ain't really worried about how easy it'll be to light, only that it does light, and as a practical matter, it needs to be in the form of can strips and/or wire. Apparently, when it goes, it goes for a good long time, and will seperate water into hydrogen and oxygen (and that's what I'm looking for, electrolysis won't do).


4) Oil can be used as coolant, though you'll have to confirm that with some of our more seasoned members. I've welded way more magnesium than I've machined. Magnesium is tough to "light" unless you have fine flakes or powder, so as long as your machining process makes chips and not flakes, you'll probably be okay.

However, sneaking in a semi-hazardous material without the boss knowing might be a bit on the iffy side. :)
Oh, it's already in the shop without the boss knowing about it (I'd left it my toolbox when I was working at the foundry. I had it there in case Pete Puma got out of hand, I was planning on slipping bits of it into the lathe so that when he machined aluminum he'd have an "interesting" time. Lucky for him I'm no longer working there.), but finding a clean mill, having the oil handy, and cleaning it all up in short order might be a tad on the difficult side.

wierdscience
08-12-2006, 09:49 AM
Cleaning out the coolant tanks is simple,since you are currently stopping to unclog a pump everyday or so tell them that since it is costing them money everytime you have to stop.Either that or just do it and don't say anything.

The scrap is worthless even seperated.

Magnesium you can use oil on,but it is easier to use a stream of compressed air and blow the chips out of and away from the cut.You want to cool them off and make them leave not stay around and build up heat to the point of ignition.Water based anything is not a good idea,if you do have a fire,it will make it burn brighter and quicker which may draw attention:D

Oh,sharp(draws blood)tools are a must.

Rustybolt
08-12-2006, 09:50 AM
and management can't seem to figure out the need to empty the chips in the oil tank,

!!!!!!!!!!!!!!!!!!!!


Every freakin week, or as needed. For our single spindles. On some jobs we cleaned our machines sumps every day. If you're running a nice long alum job, have somebody from management come out and smell the sump. Tell em that's bacteria growing in there.

Wareagle
08-12-2006, 11:05 AM
I'm currently a screw machine operator, and management can't seem to figure out the need to empty the chips in the oil tank, so I'm hoping that if I point out that it's money sitting down there, they'll clean the things out. It's getting real old having to unclog the pumps on the things every day.

If you are clearing pumps everyday because of the chips in the sump are being picked up into the system, then it is costing money everyday in the labor and down time that is being used to take care of those tasks. So, it is money sitting down there!

It sounds like your management and my management teams might have attended the same school.... Their slogan is "There is no amount of money we'll spend to save a dollar".

Rustybolt
08-12-2006, 11:10 AM
Oh yeah. When we machined magnesium pistons for compressors we used regular cutting oil.

HWooldridge
08-12-2006, 11:47 AM
You could separate the steel from the other chips with a simple electro magnet but I think for the labor expended, it's best to simply make it a discipline to empty the swarf periodically and sell it for whatever you can get. Lathe leavings are strings with a lot of air in between - mill chips are more dense but I have filled up trash cans with mixed swarf and it did not add very much weight.

Mixed steel here in Central Texas brought $1 per hundred lbs for the longest time. It spiked periodically up to a high of $4 but that dropped back considerably so I don't know what you could get at this point in time. Most scrap yards will leave a container or two to fill then you call and they come get it. I only came up with about 50 tons in all of your machines but I used a factor of 30% on the density. 360 tons "sounds" high, but if correct you are talking $7200 or so at a buck a pound.

Wirecutter
08-12-2006, 01:13 PM
What's a cubic foot of steel chips weigh (small chips, not the long, stringy ones)?

Going price for scrap steel per pound?

At what temp aluminum ignites?

The best way to machine magnesium?

(No, I don't know the answers to these, but I've got projects I'm working on that I need the info for.)

It sounds like you're planning a very, uh, interesting project there. Are you trying to "accidentally" make a thermit reaction as a safety demonstration for the management at work?

-Mark

Duct Taper
08-12-2006, 11:50 PM
A solid cubic foot of steel weighs 490 pounds, but there is a lot of air in your box of chips and will vary depending on chip size. The only way you will find out what your chips weigh is to put them on a scale.

SJorgensen
08-13-2006, 02:53 AM
I got a pleasant surprise today. I took my little pickup bed trailer to the metal yard with a load of 7 or 8 trash bags of aluminum cans from a four-plex I manage. It didn't fill 2/3 of the truck bed and not higher than the sides. It paid $92.

Tuckerfan
08-13-2006, 04:57 AM
Cleaning out the coolant tanks is simple,since you are currently stopping to unclog a pump everyday or so tell them that since it is costing them money everytime you have to stop.Either that or just do it and don't say anything.Been there, done that, got the tattoo, and sticking my arm in 100F cutting oil is getting really old.

It sounds like you're planning a very, uh, interesting project there. Are you trying to "accidentally" make a thermit reaction as a safety demonstration for the management at work?Nope. I've got the formula for thermit around here somewhere.

HTRN
08-13-2006, 11:26 AM
Warm ain't so bad, but ice cold? Blech. Grossest feeling in the world.


HTRN

Tuckerfan
08-13-2006, 11:37 AM
Warm ain't so bad, but ice cold? Blech. Grossest feeling in the world.


HTRNYeah, well, if it were winter I'd agree with you, but temps in the building are presently hovering around the mid-90s (and I work second shift) most of the time, so having hot oil splatter on you is the last thing you need.

wierdscience
08-13-2006, 11:39 AM
They do make shoulder length gloves and they do make perforated metal for building catch trays that keep the chips from ever getting in there in the first place.
Maybe make some suggestions as such and if they don't want to do it let the machines fill up and overflow on the floor,when they ask tell them why.

Me I've never worked for folks so cheap thay wouldn't let me take the initiative and fix problems.

Tuckerfan
08-13-2006, 12:19 PM
They do make shoulder length gloves and they do make perforated metal for building catch trays that keep the chips from ever getting in there in the first place.
Maybe make some suggestions as such and if they don't want to do it let the machines fill up and overflow on the floor,when they ask tell them why.

Me I've never worked for folks so cheap thay wouldn't let me take the initiative and fix problems.Oh, we've got the perforated trays, but the chips are so fine that they go right through the holes. When the oil gets stirred up it looks like flake metal paint. The tanks are filled with normal sized chips as well, but most of the time the stuff I have to scrape off the pump screens has the consistancy of steel wool. I've got gloves, but they do nothing against the heat, and management won't complain about me completely digging the chips out of a machine, provided I have all three of mine running and regularly check my parts. Given that all the machines closest to me are always running (be they mine or someone else's) and that it takes a good fifteen minutes or more to dismantle the guards on one side of the machine (which can't be running when I'm doing this, for obvious reasons) and I've no idea how long it'll take for me to completely dig the chips out (not to mention find a bin I can dump the chips into), there's simply no way I can do this without getting management to agree to some changes.

And if I let the machines overflow, they still won't let me (or anyone else) completely clean them out. You dig 'em out enough to get them back up and running, and that's it.

Millman
08-13-2006, 12:52 PM
Sounds like some companies I worked for. {{You dig 'em out enough to get them back up and running, and that's it.}} The only time we could clean the beds out completely was when the machine blew a clutch or something major like that. Like you said the chips in the sumps were like sludge. Had to use your hands, no gloves, to get them clean. Was running 5, six spindles one night, go to the tool room to surface grind a form tool, within 10 min.; I had about 60 gal. of oil everywhere. Hell of a mess to clean up. I never weighed a cubic ft. of the chips. We had an old centrifuge to spin the oil out. Used to love those machines, even though they could be a pain in the ass. One old Acme-Gridley had a crack in the bed, so had to clean the floor constantly...Things were alot more fun back then, always an adventure with screws.

lbender
08-14-2006, 03:08 PM
Tuckerfan,

The ignition temperature for pure aluminum is 1230F, lower for aluminum alloys. Due to the oxide film formed on aluminum, it is difficult to ignite in air. In pure oxygen, it tends to detonate at elevated temperatures.

Magnesium, on the other hand, does ignite readily in air. Ignition point for pure magnesium 1220F, much lower for alloys, ie, 800F for AZ31B. And if you want the ultimate, place a piece of aluminum on a piece of magnesium and heat to around 450F.

For the home shop, machine magnesium dry, no coolant. The surface finish in lathes or mills is very good without any lubrication. Sharp tools along with reasonable speeds and feeds to produce chips instead of dust are all you need. Good housekeeping is paramount, but you already knew that.

sparker
08-14-2006, 10:50 PM
I know all about those screw machines. I used to run citizen L20's, if you do clean out the coolant(oil) tank get yourself a shovel that is flat on the end. trust me doin it by hand ain't no fun. on ours there was a panel you could remove to get into the main resevoir. Oh and we didn't have any problems with recycling the chips oil or not. a penny a pound for the mixed chips tho. so we drug the chips whenever we switched to a different material.

YankeeMetallic
08-15-2006, 12:51 AM
"...Finely-powdered aluminum is used in Thermite ...Doc.
When I saw the 3 ingredients on the same page at once, iron (oxide) aluminum and magnesium that's the first thing I thought of as well; "THERMITE", yeah BABY!

wierdscience
08-15-2006, 02:01 AM
Oh, we've got the perforated trays, but the chips are so fine that they go right through the holes. When the oil gets stirred up it looks like flake metal paint. The tanks are filled with normal sized chips as well, but most of the time the stuff I have to scrape off the pump screens has the consistancy of steel wool. I've got gloves, but they do nothing against the heat, and management won't complain about me completely digging the chips out of a machine, provided I have all three of mine running and regularly check my parts. Given that all the machines closest to me are always running (be they mine or someone else's) and that it takes a good fifteen minutes or more to dismantle the guards on one side of the machine (which can't be running when I'm doing this, for obvious reasons) and I've no idea how long it'll take for me to completely dig the chips out (not to mention find a bin I can dump the chips into), there's simply no way I can do this without getting management to agree to some changes.

And if I let the machines overflow, they still won't let me (or anyone else) completely clean them out. You dig 'em out enough to get them back up and running, and that's it.

Well talk to them,the fix can be simple and cheap,like a pump intake with an endless screen infront of it.