Magnesium is 'generally' stable, however

If you somehow get it into powder or flake form, it's pretty volitile. (a pile about the size and thickness of a dime can get a tire burning once the magnesium is ignited by a small spark. We're talking 0 to metal melting hot in about .010 of a second)

Flat tire grinding on the road before the car can be stopped? It can get real scary real fast. (IIRC, BMW stopped using that kind of wheel for a short period of time a while back after a few peoples cars burned to the ground after driving on a flat and fire departments had no means of putting the fire out. Watch a race car burn sometime and you'll get what I mean)

A split or crack that can sorta grind on itself and make powdeer residue? Again, real scary if it comes in contact with a spark or something sufficiently hot. (and by 'spark' I mean like what a BIC lighter throws off, not a big flashy thing like a grinder produces)

Of course there's the actual amount of magnesium in the alloy to consider among a few other variables, so there's no need to go into a panic as it's usually extenuating circumstances that cause the fires.

Would I run magnesium wheels? Sure, if they were free or I used them strictly for racing. (I'm not 'afraid' of them persay, it's jsut that they're so god awful expensive and a lot of tire shops around here won't touch them for thier own insurance reasons)

There's a lot of people on them and it's not like they make the news every day, so even though they 'can' be dangerous, it doesn't mean they 'are' dangerous.

 

Are the 15" ???

Don't drive them, sell them to me, much safer

They are not dangerous when in good condition, they are fragile though !!
The official Campa name for the material is Elektron

 

magnesium corrodes VERY easily. it is not uncommon for big areas under the paint on these wheels to be reduced to white powder. this and the brittleness are the big reasons that many do not like magnesium street wheels.

if you get older magnesium wheels, many will suggest to strip the paint off to check for corrosion and have them recoated. i have heard horror stories of how bad they can be, hidden under the old paint. zinc chromate is the historical paint of choice, though i bet there are other kinds that will work well.

 

Magnesium wheels are cool, but they do have the fire risk. Mg does burn under water, and therefore cannot be put out with it. In the case of a wheel however, as it was stated before, it depends on the alloy. They are prone to oxidizing, they are brittle, and they could loose air faster than an Al wheel. If you have them checked very carefully and resealed you should be good to go. AKH wheels had a thing about Mg wheels, check their website www.akhwheels.com


Will

 

Wil's answer is about the best so far. The material is not only a problem if it catches fire. Much like a fiberglass body, it burns, but hotter. Few worry about fiberglass body panels. Mg is brittle. It does not work well with ultra low profile tires and roads with potholes. Mg is porous. It is not a good alloy to expose to corrosive chemicals; road salt, dog pee, brake fluid, or chemical paint strippers. The best paint/corrosion removal is by blasting with plastic beads, or if you are very careful, glass beads. The material is soft and glass beading can cut material away if not done carefully. They can be repaird if cracked, and they can be crack checked. Many vintage aircraft use Mg wheels, and repair same. In short, being aware that they really are Mg and NOT light alloy, and that they require more attention than light alloy, and MUST be treated and repaired differently than light alloy is enough for some to feel they are not worth the problems. Others like me, appreciate the LESSER WEIGHT and enjoy painted (Mg should not be left bare) Mg wheels. I have a set of REAL Mini-Lites on my Alfa (Mg) and a set of Campy's on a Ferrari (Mg), and enjoy both. Gordon Raymond

 

The Campie "mags" originally delivered on GTAs where "Electron" alloy. Very light! But also serviceable and immune to he many problems associated with pure "Mg"s

 

How about bead-blasting, inspecting for cracks and then Teflon-coating?

Search for: KERONITE

Can you imaging how easy it would be to clean Teflon-coated wheels?

 

I would be very reluctant to literally TEFLON coat the wheels... slippage at the bead area is no good.

 

True. Perhaps this area could be abraided or distressed? Carefully, of course.

But perhaps it is a non issue:

http://www.keronite.com/automotive.asp

or, specifically (scroll down):

http://www.keronite.com/motorsport.asp

 

What would happen if they needed crack repair? How would one ever get the teflon out of the pores in the alloy to repair?
Gordon Raymond

 

Thanks for all the input!!

Thanks guys, all the input has pretty much cleared my concerns! My main concern was of the Mg wheels being quite brittle and the chance of having a wheel fly apart at high speed, (or even lower speed) so I'll be watching out for those pot holes.
I knew about the fire hazard too but considered (and still consider) it to be a chain of bad coincidences - a worst case scenario or a real ugly fluke, which has been confirmed by tifosi and Gordon. As for the keronite Teflon treatment, well I'm afraid thats not quite my league - I'm more the "clean em up and paint em" guy, by nature and by budget.

This is the "Bobonite" treatment that the wheels got.
1. Carefully sand blasted with very fine grade sand at 6 bar pressure.
2. Primered, scratches and nicks filled with polyester, sanded and reprimered
3. Scuffed with scotchbrite
4. Two generous coats of grey aluminum color acrylic paint.

And here are the results!
(this is the cracked rim and you can see how badly corroded it was in the bead area at the back)
BTW, does anyone know anything about this particular design? Another BB member (Randy Lee) has a set but other than that, I've never seen them before and I only know that they are 6x14, 28mm offset and manufacterd in 1971.

Thanks again!!
Bob

 

WoW! Those are interesting. FYI, I painted my OEM Mini-Lites the same way you did, but added a clear coat after the last color coat. More gloss than when new, but not "fake" like new powder coated wheels. If you want to rescue the cracked wheel, look up a local small airport that has qualified mechanics. They will be able to tell you who they send Mg parts out to for repair. It involves electric welding under a hood with a no O/2 atmosphere.

Gordon Raymond

 

Looks great!

 

FWIW, magnesium including elektron, once it has been stripped, does benefit from a Dow 9 coating (mil spec) prior to paint build up. Also, stripped magnesium wheels should not be exposed to any moisture. Usually Dow 9 process and similar is provided by aircraft service places - they will strip and then immediately coat. There are some other more modern magnesium protection/passivating processes as well.

 

Hey Bob,

Thanks much for inviting all this info. I think that I will try to find an aircraft shop to refinish mine. Will report and post "before" pictures soon.

Regards,

 

Anyone know if the original Turbinas are this Elektron alloy or a "pure" Mg alloy?

I did find a thin turned up shred of metal on the inside of one of my Turbinas, tested it by propane torch. Got the typical hard to start, then can't look at it brilliant white flame of Mg or something mostly composed of it.

Mg is very hard to start as a chunk of metal, but when it goes..... And water will actually feed the flame, it will take it apart and burn the oxygen.. Got to smother it with sand or something. But, the likelyhood of lighting up your wheel is pretty low, unless you try to stay on the freeway that last 3 miles after the tire goes..

The corrosion concern is important. I heard of using a dental pick or similar tool to poke around at suspect areas... some have discovered big "cavities" under the paint. I had just tiny surface corrosion areas, luckily.

I also remember Digest posts about painting... there is some color of BMW Silver that is supposed to be just perfect to match the stock color... Good luck with your painting! Mine really need it someday soon...