Mag Wheel Material question

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Good Day,I am restoring some old (1960-1970) American Racing Wheels.  Does anyone know a non destructive way to tell if the material is aluminum or magnesium?Thanks,Greg
Reply:Don't know for sure, but I believe they are aluminum. Love those old rims.  If my memory doesn't fail me, the most popular real magnesium wheels of the day were Halibrand.  Real mag is a darker brownish-gray color and aluminum, well  you know.  I do know that magnesium burns with a bright white intensity though, so be careful.  They used to have a hard time putting wheels out when they crashed.  Water won't put them out but make them burn hotter.  I thnk they use mag for underwater flares.Hobart 140 Handler w/ gasHyperTherm Powermax 380 Plasmaoxy/acetylene
Reply:Thanks, Most were aluminum, but American also made a few Magnesuim and this set is darker gray unlike some others I have that look and weld with al TIG.  It's that whole fire thing I am afraid of.Thanks,Greg
Reply:You got my curiosity up being an old drag racing fan and working in the industry.  I did a quick search and found a great site that has the history of racing wheels and maybe that will help.http://www.roadsters.com/wheels/#IntroHobart 140 Handler w/ gasHyperTherm Powermax 380 Plasmaoxy/acetylene
Reply:If you're still in doubt about the material, take a few shavings from an inconspicuous area of the mag wheel. Hit it with your torch (propane should do, I think) If the shavings burn you have your answer.Have plenty of sand nearby. It puts a mag fire out in a jiffy.Last edited by wallythacker; 02-16-2007 at 02:32 PM.Craftsman 230a Buzz-box,  Lincoln 140T & 180T, Century K2789, PUROX W202 O/A14" cheapo chop saw that cuts straight and square!A toolbox of the cheapest Chinese tools money can buy"Real" tools all old reliable Husky/Craftsman/Proto stuff
Reply:Great  minds think alike!!!  It is that very website that got me thinking these might not be AL.  I am thinking about filing some chips off the back and lighting them on fire to see if they glow.Thanks,Greg
Reply:Sand, What a great idea! Thanks,Greg
Reply:Aluminum dust also burns. Remember when Mcguiver got locked in a tractor trailer with a car battery, some aluminum and a car exaust? He shaved a bunch of chips, used the exaust as a cannon and ignited it with the battery.  At my job piles of aluminum chips under the saw flare up occasionally when extention cords are lying in them and arc. They never stay lit though. I think you need aluminum dust for that I remember seeing a tv documentary about how Ricky Nelson's plane crashed because it got made out of magnesium back when aluminum was in short supply and the metal caught fire. The difference is that big pieces of magnesium catch fire.Last edited by 12,000 Doors; 02-16-2007 at 09:18 PM.
Reply:In a high school chemistry class, back when teachers were permitted to do such things, I recall a teacher pouring some liquid into a test tube with a little powdered magnesium and it fizzed up and ran all over the lab table.  Seems to me it was common vinegar but maybe not.  I think I'd ask a chemist for a method to be sure.
Reply:Thanks for all the input!! Over the weekend I took a machinist 3 sided scraper and took a shaving off the back of this wheel and another from a wheel I know is aluminum.  Then as suggested above, I held the shaving with a needle nose and burned it with a propane torch.  Both shavings turned red after about 4-5 seconds but neither glowed or burnt like a flare.  I think the wheels are aluminum.   Several years ago I tracked down a retiree from American racing and he said they used 356 aluminum so I should be able to repair weld them without too much trouble. I loved that show Mcgiuver!My with excelled in chemistry, I will ask her about the test tube idea.Thanks,Greg
Reply:Aluminum powder mixed with iron oxide makes thermite.  It used to be used when welding railroad tracks.  It burns in a very spectacular fashion, burning magnesium is usually used to ignite it.
Reply:There is (or used to be) a spring opener motorcycle party up in North Dakota every year.  One of the guys in the club that sponsored it was also a VW fanatic.  One of the (many) highlights at the party was taking a VW engine block that was made out of magnisium and throwing it in the bonfire.  Sometime in the middle of the night when everyone was good and toasted they would take water based fire extinguishers and squirt the red hot engine block...that thing would explode! sending flaming molten metal in the air...quite a spectacular show...although I would not recommend this at home...  MM175 MIGCutmaster 38 PlasmaCraftsman 30gal compressor4x6 HF bandsaw1hp HF floor drill pressRyobi Cutoff SawAssorted grindersNot enough time
Reply:Yes, I have heard about putting engine blocks in a bonfire and I remember burning a strip of magnessium in 8th grade chemistry and a small .010x.125 strip of magnesium would glow and burn very bright.  It was also hard to put out the flame.  This is why I was concerned about welding on these wheels without knowing for sure the material.  I didn't want my wheel to go up in flames even if it would be a spectacular sight.Thanks everyone for the input.
Reply:If you spray common acid type aluminum wheel cleaner on bare mag, it will darken and corrode almost immediately.I've burned some mag drilling and threading chips with a torch, and they really didn't burn that well, but they did burn. A ribbon-like piece will burn much better than a thicker piece.David
Reply:I've never seen an actual magnesium fire, but I have done some industrial cleaning(with water) underneath some magnesium milling machines. First thing when the job starts, they show everyone how to use a "D" fire extinguisher. Basically a bucket of sand, just pour it into a berm around the fire to keep it from spreading, then wait for it to burn out.
Reply:Be carefull with old magnesium wheels. unless the are well cared for the corrode like crazy and get really brittle. Great for period correct restored show cars but not so good for the street.