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Posted: Wed Dec 10, 2008 2:14 pm
by john bunsenburner
I am not sure if that last remakr was plain dumb or if you forgot something but: Aluminium oxidizes to fast and so "strongly" that it will strip the o2 molecules from the h2 ones in water. If you do it under water, chances are you will either ge tlots of useless oxide or you will blow your self up. Personally, even though i am unsure of what you plan on doing, I would buy the Al powder. What amounts are you thinking of?
Posted: Wed Dec 10, 2008 2:58 pm
by mark.f
Aluminum has it's own specific risks when ball milling. If you are not knowledgeable in the subject already I wouldn't recommend whatever project you're working on.
Posted: Wed Dec 10, 2008 4:25 pm
by Lentamentalisk
Its actually quite cool. Rather than form little flakes of corrosion, like iron does (think fish scales,) the corrosion creates a solid coating, that protects everything under it from further corrosion.
Posted: Wed Dec 10, 2008 4:33 pm
by john bunsenburner
This corrosion is so strong it will rip the Oxygen from the Hydrogen in water if the outer layer is take away. This can be achieved by putting soda cans into lye and gently heating it. Alot of hydogen gas will form, the reaction is similar to the one between acid and metals(ussually copper). If you want to see how muh the layer protects the aluminium look up aluminim and mercury(this is why thermometers are forbiden on planes) o not try it though because of the brain damaging fumes that come from mercury(Or do you think the "mad hatter" had nothing to do with the fact that hats where polished with mercury to make them shine?).
Posted: Wed Dec 10, 2008 4:59 pm
by ramses
the lye serves to dissolve the al2o3 coating. therefore, unless you grind under a strong base or acid, or some metal that prevents this oxide coating from forming. this problem won't cause one to "blow oneself up" unless that person bothers grinding under an inert atmosphere, and then pours the powder into water.
grinding under water does nothing to keep corrosion down. it is to keep dust down to prevent a aluminum dust cloud from igniting. if you were serious, you would put charcoal in the powder from the blender, and ball mill under an inert atmosphere, in a heat resistant, air tight container. that container could possibly be heated, causing the carbon the aluminum from corrosion. if the carbon fails, chances are the powder would ignite, and you would be burned.
Posted: Wed Dec 10, 2008 8:17 pm
by CasinoVanart
One word- THERMITE.
We are not supposed to discuss things of this nature here, there are plenty of pyro sites around dude

Posted: Thu Dec 11, 2008 3:15 am
by john bunsenburner
If you are seriously making thermite then chances are you will get killed, dont!!!! Maybe a mod should close this thread, it is gettign too unsafe and off topic, further more it is against the rules is it not?
Posted: Thu Dec 11, 2008 4:10 pm
by ramses
making(playing with) thermite is not as dangerous as one would think. all that is required is a suitable delay mechanism, dry sand/dirt, and a little common sense.
[rant]
you get intro trouble when you set it off directly with a flash capacitor on a paper plate over your crotch, in your second story bedroom, above your hot water tank/water softener/ gas welding rig. I am not a huge Darwinist, but if someone is stupid enough to play with MOLTEN STEEL inside their own home with only a paper plate to contain it, you deserve to have your testicles burned off with molten metal, and then your house blown up in a gas explosion. if that is the case, get it on film so I can post it on Darwin Awards.
[/rant]
on a more serious note, don't play unintentional flammables, and DO NOT TRY TO PUT IT OUT, EVER
Posted: Thu Dec 11, 2008 5:06 pm
by john bunsenburner
Better yet: Dont Even Think about making it, if you have to ask how to make it then i doubt you can make it(I have done that mistake many times to, but then i noticed it is seriously dangerous). Thermite is over 2000°C hot, cannot be put out under normal conditions. Chances are you will get hurt, maybe a mod should really shut this topic down, it is a major safety hazard.
Posted: Thu Dec 11, 2008 5:29 pm
by ramses
sorry to hijack this thread, but thermite isn't that hard to make, and is not as dangerous as you wish to portray it, if common sense is used. i certainly don't suggest making hundreds of pounds of it, and using it to cut a car in half lengthwise like the myth busters, but it does have the potential of use in construction of cannons. casting metal parts and non-incendiary projectiles. basic research would yield the main hazards, and how to deal with them effectively.
If I had the parental authorization to buy the necessary chemicals, I would gladly set off a few pounds in my sister's sandbox once it dries out, just to prove a point.
Posted: Thu Dec 11, 2008 5:45 pm
by PCGUY
As others have said, be careful what you stick into a ball mill. There is a proper procedure for everything, and I would suggest checking out a pyro site that strictly supports pyrotechnic safety measures above all else.