Reply with QuoteToo many pieces to that puzzle though. Silver nitrate is easier, and just as safe.
Archimedes law
Find the volume of the part by putting it in a cylindrical waterbucket. Measure waterlevel before and after the part is in. The difference is the volume. Then weigh the part. You can now find the density. Al is 2.7kg/liter and Mg is 1.6kg/liter. Safe and simple.
Best regards
John
Too many pieces to that puzzle though. Silver nitrate is easier, and just as safe.
Stop talking about it and do it already!!!!!
(Note: The opinions expressed in this post are my own and are not necessarily those of CNCzone and its management)
Re: Archimedes law
LoL, damn engineers!Originally posted by motordude
Find the volume of the part by putting it in a cylindrical waterbucket. Measure waterlevel before and after the part is in. The difference is the volume. Then weigh the part. You can now find the density. Al is 2.7kg/liter and Mg is 1.6kg/liter. Safe and simple.
Best regards
John
'Rekd
Matt
San Diego, Ca
___ o o o_
[l_,[_____],
l---L - □lllllll□-
( )_) ( )_)--)_)
(Note: The opinions expressed in this post are my own and are not necessarily those of CNCzone and its management)
Ha!!
Stop talking about it and do it already!!!!!
(Note: The opinions expressed in this post are my own and are not necessarily those of CNCzone and its management)
magnesium also rusts nearly instantly with conyacy with water
how do they keep mag wheels clean?magnesium also rusts nearly instantly with conyacy with water
robotic regards,
Tom
= = = = =
"Here's champagne to our real friends, and real pain to our sham friends"
Real Mag wheels are basically magnesium.
The normal mag wheels used on cars are not magnesium but aluminium with a small (few %) of magnesium.
Great use for a magnesium stick is to use it in your iron casting project. Using its high burning temperature to set off "termite" mixture of iron oxide and aluminium powders
Using ordinary rust with aluminium powder you can quickly get melted iron. Of course there are many issues related to such quick reaction but it is hell fast.A combustion reaction is often an oxidation and reduction reaction. Since the oxidation of one substance involves the reduction of another, this type of reaction is often called redox reaction. In the following reaction,
2 Al + Fe2O3 = 2 Fe + Al2O3
The element Al is oxidized, but Fe is reduced. This reaction is also called a displacement reaction because Al displaces Fe in the oxide.
Of course the Fe2O3 and Alum powder have to be very fine to be of any use, I have seen this experiment on my chemistry class in high school and it was terrific. After a bright light of the magnesium stick a red stream of hot iron precipitated in a sand bucked located below.
The aluminum powder needs to be REALLY fine though. Aluminum shavings from milling will not work
-Please check out my webiste-
http://www.teilhardo.com
Termite powder (iron oxide & aluminium powder basically) normally is started with a magnesium cord, other heat sources are not enough hot...
powders of aluminum are explosive
Be careful burning metalic powders.
Depending upon the particle size (surface area to volume or sav) you might get a particle size which may go beyond a slow or quick burn rate.
The rate of reaction is reportedly far greater than the sav, the rate of reaction is inversely proportional to the particle radius,but by an exponential amount.
A really fine particle has much more surface to burn its relatively small mass.
In other words ,"KABOOOOM!!!!).
A little variability one day may cause something unexpected.
But now you might expect it!
By the way, some early rocket fuel consisted of powdered aluminum and diesel fuel, some solid fuels may also incorporate powdered aluminum.
-Mark
Last edited by MHINK; 02-07-2005 at 10:34 PM. Reason: revision
I seem to recall reading somewhere that if you put a few small drops of distilled white vinegar on magnesium it will bubble furiously while aluminum will do nothing. I'll have to check to be sure.
Some many years ago some magnesium found its way into a very large (30ft high) camp fire. Magnesium was a nose wheel from a cargo plane that failed xray testing. Weighed about 80lbs. When it finally got started it burnt the entire fire down to ashes in about 10 minutes. Anyone venturing closer than 30ft or so got sunburn and some lost eyebrows. As it was at night it was seen by aircraft and reported as a flight hazard. Everything looked like one continuous flsah from a camera - for half an hour. The fire brigade arrived and tried to bury it in sand. It didn't kill it, just turned the sand to glass. In the morning the hole was about a foot deep, four feet round and glazed.
Anyhow; magnesium rings far less than aluminium so its usually easy to detect by ear if you've got a known bit of Al, magnesium damps sound much better than Al. Magnesium is noticeably ( 1/3rd) lighter than the equivalent volume of Al. but is far harder to dent. The corrosion is different too. Al forms a relatively flat corrosion layer, even in the presence of salt, Magnesium will form high powdery white growths. If the mag has a surface finish the Nitrate test doesn't work so make sure you cut back to the metal base before testing it. If its a pure mag alloy like used in wheels or gearboxes simple pool or battery acid will bubble on clean mag. where it would not on Al.
Andrew
OK throwing all caution to the wind, and with a great deal of stupidity, you can turn your hot pot of castiron into good quality steel be .........yes you have guessed throw in a chunk of magnesium.........better also learn how to run....very fast too.....
wont catch me doing this
Magnesium
Hello,
the only way you can turn castiron into steel is to remove the carbon. Castiron has more than 1,2%C (if I remember correctly), Fe with less C than that is steel.
When introducing Mg in the castiron melt you get nodular cast iron, which is a very tough cast iron.
Regards
John
Hi John,
I thought that by adding magnesium to molten cast iron the effect of superheating the iron burnt off the carbon in the iron. the following passage gives full details.
Gray iron is brittle but soft and easily machined. White cast iron, or white iron, which is harder and more brittle, is made by cooling the molten iron rapidly. The carbon remains distributed throughout the iron as cementite (iron carbide, Fe3C). A malleable cast iron can be made by annealing white iron castings in a special furnace. Some of the carbon separates from the cementite; it is much more finely divided than in gray iron. A ductile iron may be prepared by adding magnesium to the molten pig iron; when the iron is cast the carbon forms tiny spherical nodules around the magnesium. Ductile iron is strong, shock resistant, and easily machined.
which means your are almost right, and more right than me!!
Regards
Roger
Hello Roger,
thanks for your reply. Again, adding Mg does not remove any carbon from the melt, it only changes the shape and distribution of the graphite. To remove carbon, one needs to add oxygen (O2). The O2 dissolves the carbon and leaves the melt as CO or CO2. The Mg causes the graphite to grow as spheres, where as in "normal" castiron the graphite grows as flakes. It does not remove any carbon in the process. The Mg is vaporised and the vapor travels throught the melt and lowers the sulphur content and promotes formation of spherodial graphite.
regards
John
Most domistic trans cases are Aluminum but REKD is right VW heads are ok mag usualy turns almost black from weather I heard of a guy sanding on a VW case to pretty it up and his shurt was filled with the dust and he made a spark when he hit a stud in the case and he lit up like a road flare to make mater's worse the polister shirt shrinkwrped him the chips from milling do make an exelinte distress flare. There are a lot of nice castings in the scrap thies days. alot of aircrart castings are also Mag
Ok, sorry guys, but I had to register to say this.
I was laughing at this thread when I saw this......
All other amusing methods aside, that is indeed the easiest way to test. Its pretty much standard practice in welding; an "old welder's trick" of sorts.Originally Posted by DragnsBane
Just put a drop on the metal; if it foams it's magnesium, if nothing its aluminum.
Cheers, I'm off to read more about ball screws.......
Last edited by CypherNinja; 05-17-2006 at 11:54 PM.
When I was in the Army,I saw a guy set a Thermite grenade on top of a V-8 engine block and pull the pin.About 15 seconds later,it dropped on the ground.I was impressed.At one time,thermite was commonly used to weld thick iron sections.I really don't think it would be an economical method of melting iron for casting.Not sure what is in that massive white cloud of smoke either but,I am sure it is not healthy to breathe it.
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