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myfarm
01-07-2006, 12:01 PM
Hi.
Are alum car wheels any good for casting ?
I can get 4, but want to know if it is worth breaking
them down.
Thanks
Mike

Daggoth
01-07-2006, 02:16 PM
Hi myfarm,

Personally, I wouldn't mess with them. A lot of wheels are made out of magnesium and I wouldn't risk it. You don't want a magnesium fire. There is no stopping it once it gets started.

Have a good one!

Daggoth

Anon
01-07-2006, 04:52 PM
Do an acid test to see which you have (magnesium reacts pretty readily with weak acids like vinegar, and aluminum won't be affected).

If they are aluminum, go for it, because they're probably a decent structural alloy. If they're magnesium, don't bother. People have successfully used magnesium before, but in my opinion, it isn't worth the risk of destroying a good crucible and maybe even your entire furnace setup. To break the wheels down, start a nice big wood fire in your charcoal grill or elsewhere. You can either wait until they get "hot short" and crumble them up with a hammer, or you can go on and let them melt completely. Sometimes it's hard to pull the aluminum out before it melts, but it won't hurt your grill if it does. The only problem is that you may make chunks that are still too big to use. If you can let it dribble into an ingot pan, then that will keep it from forming oversize chunks. You can also do it in your furnace and let it dribble out the drain hole, as long as you're sure they aren't magnesium.

Lou
01-07-2006, 10:54 PM
Alloy wheels are o.k. casting alloy. You can tell alot about the wheel by how easily you can file it and how light it is. A vinegar test would be a good idea if you're worried about magnesium fires.

You might even be able to make a fire pit with a shallow depression in the bottom and let the aluminum melt and flow to the bottom (like a rudimentary cupola) which would have a channel cut into it.. Granted, there will be loss to oxidation and probably hydrogen porosity.

Adam Ziegler
01-07-2006, 11:41 PM
A lot of my aluminum comes from wheels. I actually have never come across a magnesium wheel... but I have seen lots of people call aluminum alloy wheels "Mags" !

Anyway... I broke mine down when ever I had a bonfire going. About 3/4 of it ended up crumbled by a sledge... the other 1/4 melted out into a big blob through the fire. It can be a lot of work, and you can loose a few pounds of aluminum in the process.

Next time I get my hand on some, I might rip it up with a cutting torch, or maybe even band saw it up.

phillip
01-08-2006, 01:43 AM
From what I have read moat aluminum wheels are a 386 aloy and great for casting! IF you find out what manufacture made them and look up the specks for them?I know some GM componets list the alloy in description
for each componet like newer transfer case housings are magnesium and
some weels are al386 .
Just another thought when searching for info.
Happy casting
Phil

Techno
01-08-2006, 02:57 PM
I doubt you'll come across real magnesium mags. Maybe if they're from a special race car. For street and especially factory wheels not much chance.
If you disbelieve this try doing a search for rims made of magnesium.
Look in some online catalog.

Adam Ziegler
01-08-2006, 03:49 PM
I doubt you'll come across real magnesium mags. Maybe if they're from a special race car. For street and especially factory wheels not much chance.
If you disbelieve this try doing a search for rims made of magnesium.
Look in some online catalog.


Right... this has been my experience too... I work with a guy who races motor cycles. He said he has seen mag rims for cycles, but those who use them are few.

Bob S
01-08-2006, 04:14 PM
myfarm, I tried to post a reply yesterday but it wouldn't post. In any case over the years I have probably melted down over 200 alloy wheels for the aluminum and have never come across a magnesium wheel in the bunch. When I'm in doubt about a metal being mag I file off some of the metal and toss it into the furnace and if it flares up like a kid's sparkler then I probably have mag.

My main supply of aluminum for casting comes from a transmission rebuilding shop that will sell me the cases below market price. This price is less then straight aluminum prices since they have steel in the cases and so they get docked. I break the cases up with a converted log splitter and remove the steel and at the same time reducing the cases to pieces small enough to fit into the crucible.

However, alloy wheel aluminum is by far a nicer metal for general casting because of it properties. It doesn't require large shrink bobs and will pour in thin cross sections without cold shorting. It also polishes up nice and usually doesn't get gassy like some of the other alloys. It, however, doesn't machine well and needs to be heat treated or allowed to age harden before trying to machine it. The only other draw back is breaking them up. They are so ductile that they bend before they breaking. So it is slow going when reducing them down in size for melting. If I could get a steady supply of alloy wheels I would use just this aluminum but I need regular supply so have to continue to get the trans cases for most of my regular casting jobs. Bob

allen hammack
01-16-2006, 01:18 AM
this is just my [possibly misguided] understanding on the matter: if im not mistaken those little emergency fire starter strikers sold @sporting goods stores are made from magnesium and lit by striking the flint thats integrated, so i cant imagine that anyone in their right mind would make a wheel made purly of such material; Especially when the only thing separating that wheel and an ignition source (pavement) is a small area of rubber. please don't think im being antagonistic, as i wrote_this is just my understanding.
happy casting, young'n
P.S.- i welcome any corrections as i may only learn from being incorrect

Cyrus
01-16-2006, 01:51 AM
Well, if your tires are so worn off that they are... gone, and you're slamming on your brakes/accelerating hard enough to catch your rims on fire, then you've got larger problems than a burning rim. If you survive the accident/chase/whatever, then a burning rim might be a relaxing sideshow...

Gasoline is also highly flammable. Who in their right mind would put that in a car?

Cy

allen hammack
01-16-2006, 02:30 AM
touche^

Anon
01-16-2006, 03:49 AM
Besides, magnesium wheels aren't pure magnesium, but an alloy. Some of those alloys, while still flammable, are pretty hard to set off. I once found a lawnmower body made of magnesium alloy, and it wouldn't light, even after several minutes under the direct flame of a blowtorch. Note that I wasn't trying to light the whole thing on fire (which would have been highly dangerous)--only a small piece. I suspect that it contained more of other metals than it actually did of magnesium. I'm sure that you could light it on fire if you melted it down, but it isn't always easy.

neophyte
01-21-2006, 03:50 AM
Not to hijack the thread , but wouldn't a reciprocating saw be the easiest way to bust down these wheels . The saws have gotten cheap enough that a person could cut metal with them and not be put out a lot of money ? I know that as soon as I get a saw I plan on trying it on a wheel and on a transmission. ANd for that matter on a old propane water heater to make a ball mill out of , since it is so easy to get used propane water heaters.

Anon
01-21-2006, 04:00 AM
Well, if you own one that isn't battery-powered. My battery one dies in about a minute, or about 5 pieces of angle iron. And holding it still is almost as much of a workout as hacksawing is. It'll probably work, but it's still not easy.

neophyte
01-24-2006, 06:22 AM
I am planing on buying a 9 amp rigded as that is what most of the contractors around here are going too( 90 dollars at home depot) , and they have a life time guantee. should be good enough to cut 1/4 plate steel is what my friend at the junk yard is telling me , in fact they use them more than thier smoke wrenches any more unless the cutting job is very big.

Techno
01-24-2006, 08:47 PM
Aluminum sucks when its sawed. The sawz all blades gum up or burn up. I can cut a 1/4" thick plate with one but I'm doing it with plenty of lube. Even then the blade gets burned. The other problem is does the saw blade recipricate or does the blade hook onto the metal and the metal sheet recipricates? Another nice feature of cutting a sheet is it acts like a sounding board!
A portaband works pretty well but of course is limited by its throat.

One of the shops recently bought a metal cutting circular saw. I understand it works great. I don't know how well it would work on aluminum though. Its not an abrasion wheel but a carbide tipped circular saw blade. The saw is built for this. Both blade and saw are $pensive.

For breaking up aluminum I think heat is the best. Just crumble the thing smaller.

Tim
01-24-2006, 09:35 PM
Aluminum sucks when its sawed. The sawz all blades gum up or burn up.

Yeesh, use some WD-40 or wax for Pete's sake.

(FYI, this is the only application you should use WD-40 as a lubricant. It's "water displacer 40", not "oil 40", and there's a good reason.)



For breaking up aluminum I think heat is the best. Just crumble the thing smaller.

Well, if you like wasting heat. It certainly works, but do doesn't a two ton safe and a crane...

Tim

Anon
01-25-2006, 12:28 AM
Note that this type of thing is why my new furnace is designed to melt its own ingots, from any scrap narrower than the furnace bore (14 in, more or less). If you have a place to start a respectable bonfire, then go for it. Just make sure you don't get any puddles of aluminum that won't fit in your crucible. I tend to avoid sawing up scrap unless I have to, since it isn't the quickest way to break it down. For engines and stuff, a sledgehammer is pretty effective, but on a round rim, it's more likely to propel the thing into some part of your anatomy than it is to break it down. The same thing would happen with a log splitter, which some people use. Sawing is okay, but it's going to be pretty slow, and you probably aren't going to like it much. The vibratory force of the saw, especially when making heavy cuts, is pretty annoying. Hacksawing will be smoother, but it's hard work, and even slower than power sawing. I use light oil for cutting on aluminum. WD-40 lubricates a bit more, but the oil sticks around longer.

As far as circular sawing, it will work, but I wouldn't recommend it. Expect to be lacerated by a cloud of flechette-like aluminum chips, and don't be surprised if your saw picks up the work and throws it (or you, depending on which is clamped down better) through the nearest window. Use an old circular saw, too--you might kill a new one. You don't even have to have a metal-cutting blade--those are really for steel. Just don't expect it to be a clean or neat process.

Fire is the way to go, if you can manage it. It's definitely the least amount of labor, and probably one of the least dangerous.

Techno
01-25-2006, 02:21 AM
On the circ saw. I don't think a regular wood saw is advised. I know the battery metal saws are a slower speed so assume the large type are too.

Tim
01-25-2006, 02:40 AM
I've heard of table saws and routers being used to cut and shape aluminum, respectively. Obviously, you must protect yourself *everywhere* because the chips WILL find you. :P Go carefully, slowly, and stand out of the way if it catches!

Tim

Anon
01-25-2006, 03:48 AM
Well, truthfully, I wouldn't advise it either way. It's one of the more dangerous things most people can do in their shop.

I would also advise you to stand out of the way before it catches, because it will move faster than you will. And it will catch, if you do this any time at all.

If you protect yourself from the aluminum chips, whatever you use to protect your body with will be shredded in short order, unless it's kevlar or something. If you don't protect yourself, your skin will be shredded. Even if you do protect yourself, you'll have cuts everywhere. This isn't like normal sawdust--the chips are big, and they're razor sharp.

It doesn't matter how careful or slow you are, the cutting edge will grab a chunk of aluminum, claw itself into the workpiece, and either throw it, you, or the whole workbench, or stall the saw motor. This kind of thing will happen constantly. You can turn the blade around so the teeth are backwards (and it will climb out of the cut, not into it, when it binds), which works well for thin sheet, but on thicker stock, it will gum up and burn the edge off the teeth.

Daggoth
01-25-2006, 04:11 AM
It may not be advisable but I always use a 7 1/4" circular saw with a 24 tooth carbide tip blade to cut aluminum. Granted I don't cut anything thicker than 2" with it. It works good as long as you don't try to force the blade through. I use light pressure and let the blade do its job. I also use a sharp blade and never a dull one. If the blade starts to get dull I get a new one.

I do advise using a face shield and secure the piece your cutting.

Use your head and be careful.

Daggoth

Tim
01-25-2006, 01:59 PM
http://groups.google.com/group/rec.crafts.metalworking/browse_frm/thread/947fd276e186df5

Techno
01-25-2006, 11:17 PM
Circular saw blades can be bought with negative or positive hook angle. A radial saw doesn't use the same as a table saw because of this grabbing feature. A blade above the table uses negative angle and below the table positive, I could have that reversed though. :)

What I was referring to. It was not a table saw or any other type of wood working machine.
http://www.mkmorse.com/

Anon
01-26-2006, 03:09 AM
If you buy the one specifically designed for aluminum, it will be both better and safer than a generic blade. It will bind and "climb into the work" much less, and it will cut easier. The chips will still be a problem, but a bunch of annoying-but-minor lacerations is a lot better than an amputated limb or impalement with a piece of aluminum. I still wouldn't advise using it on a table saw; it's a lot less dangerous to have a circular saw kick back than it is to have a table saw throw a piece of aluminum.

cchardwick
02-20-2006, 04:34 AM
I recently came across some rims and found a good way to melt them down. Cutting or busting them up is too dangerous for me. What I did was to put them at the bottom of a camp fire and get it blazing. They melt in no time. The next day when the fire is out, dig down a little in the bottom of the firepit and dig out the aluminum. It comes out like a honeycomb thing that is easy to bust up cause the ashes go in between to keep it pretty much easy to bust up. Watch out though cause a silver snake will likely come out from under a rock around the fire when it's going!