Technical Dumb question: how can you tell if a wheel is magnesium?

I have a pair of 15x7 strait spoke wheels that sort of look like magnesium. They have zero markings of any kind on them. How can I tell if they are magnesium? They are mounted on tires and both tires were flat. I know magnesium will bleed air, so I aired them up and will see if both eventually go flat. I also filed a small area on the back and put a lighter to the shavings. They sparked slightly.

Is there any other method on how to tell if these are magnesium or aluminum?

 

Chris, don’t you know they are all “mags”. Seriously not a dumb question, I have no idea either.


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Those look magnesium, but then again they don't. The white corrosion is a good sign. I would care fully remove the tires (do not let a tire shop that has the old center mount tire machine mount the wheel in them, they will probably crack them.) and inspect the inside. There is almost always moisture inside a wheel and it will eat the magnesium up. The centers have the right shade to be mag, but the rims don't. They don't take long to lose their polish and those look like they haven't been polished in a long time.

Take the tires off, and see how much they weigh, they should be pretty dang light if they are magnesium. Aluminum wheels like that aught to be around 8 to 10 pounds id think for a 15x6 which is what those look like. Mag would be around 3 to 5 each

 

They appear to be aluminum from your posted photos. Older, seasoned mag would be much darker than what I can see of the too bright outer rim section(s)........... unless they were pretty new. Of course, if they were unmounted, the lightweight would be a big clue.
Even if they turn out not to be mag, they are still very cool wheels.

 

A drop of vinegar will bubble if they are magnesium. Do it on the backside

 

The magnesium wheels get very dark with age, the whole wheel including the lip would look the same on most magnesium wheels.HRP

 

Plus 1. Drop of vinegar

 

Thanks, the weight is a good idea. I know magnesium is lighter, but I didn't know if was that much lighter. I didn't even think about it but I have some loose 15x7 aluminum 5 spokes I could compare the weight with. On these, the centers have been painted, the rim and backside is chalky. Hence the color difference.

 

If the centers have been painted, they are almost certainly aluminum. but who cares! they are one of the best looking wheels ever made!

 

Excellent info, thank you!

 

I don't really care, but want to sell these wheels, and want to price them accordingly. As you know, there would be a world of difference price wise between the two materials.

 

No doubt, there is a "tad" of price difference between the two...

 

not with an acetylene torch!!!!

 

Welp, one will make a rather effective bonfire the other won't.

I'll see myself to the door.

 

Due to the shape of the wheel I say they are magnesium.

 

If those are magnesium, they are in really nice condition....

 

Light them on fire. If the fire is crazy intense and water makes it worse, they were Magnesium. Sorry...there is a smart ass in every crowd right?

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I have a set similar I need to identify the manufacturing material. I know there crazy light. You can balance them on one finger easily .

 

That's what I was going to suggest, well since you posted it before I did , does that make you more of a smart ass than me? or does it just recognize you as being the first or #1 smart ass of this particular crowd or thread?
That would be a hell of campfire starter.
Ok I was just funin with ya, I figured a little humor this morning may help the ones that might be a little over celebrated from last night.

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Any acid even orange juice will make mag bubble.

 

I had no idea it would be that simple. HRP

 

If they are that light they'll be magnessium. You really can't mistake the weight of a mag rim compared to an alloy one, the difference is so noticable.

 

Thanks. Mine are 15x6.

 

Scrape a shaving from ctr rear side, then method two mentioned.

 

If they don't seem too heavy, they are aluminum. If they seem unbelievably light for their size, they are magnesium.
I'll vote.....aluminum.

 

Magnesium is about 33% lighter than aluminum, so while not crazy light they will be lighter if they are in fact made of magnesium.

My guess is they're aluminum, though.

 

This is getting good, we should start a pool!

I guess they are aluminum as well. But I would hate to sell them cheap and then figure out what I had. They are bitchin wheels, I just don't own anything 5x4.5"

 

Aluminum?
Might as well send em to me I'll turn em into a grinder stand.

 

Been there, done that (kinda).
It was a chip bin full of magnesium ribbon and cutting oil on my lathe at work many years ago, and yes, don't get water near a mag fire, learned a valuable lesson that day.

 

Holy shit! I think they are mag! I did the vinegar trick, on the wheels in question it bubbled, on some regular old aluminum wheels it did nothing. Wish I could post a video, in the first picture you can see how stirred up it is, looks like mini fireworks going off inside the vinegar






Regular wheel