metal question about welding

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I'm quite new to welding, and I've got a motorcycle engine case I need to fix, its cast magnesium, and I dont know what kind of welding procedure to use to properly weld it.   I dont exactly want to destroy the case because trying to find new is like trying to start a fire underwater.
Reply:you will definetly want to TIG weld it in my opinion. I've welded quite a few that were cast aluminumn but never magnesium. I'm sure there is someone here that can point you to the correct rod & sheilding gas for that application.Just out of curiosity what kind of bike is it?  I'm not had any experiance before with mag. engine cases.
Reply:The bike, is an 87 Kawasaki Ninja 1000R.   I had some WONDERFUL luck and it threw TWO rods on me, the first one I fixed, then it threw the second one after that. now I'm trying to save the motor so I can  actually RIDE the bike instead of just look at a big 600 pound paperweight in my driveway.
Reply:Hmm.  There's a common denominator here.  Why is it throwing rods?  Is it stock and well-maintained?
Reply:Its stock,  the first rod was thrown because I suspect someone screwed with  the motor, and loosened some bolts/nuts in it,  the second one, was the same problem. I'm going to be pulling more shrapnel out of the oil pickup screen now, and redoing EVERY bearing at this point to be safe.
Reply:you'd better be careful...ever see magnesium catch fire?you will not be able to put it outold v.w. engines were made from it...get one of them burning and it would go on for days.... ...zap!I am not completely insane..Some parts are missing Professional Driver on a closed course....Do not attempt.Just because I'm a  dumbass don't mean that you can be too.So DON'T try any of this **** l do at home.
Reply:Originally Posted by zapsterever see magnesium catch fire?you will not be able to put it out
Reply:well, this is interesting, but doesnt help me much on finding out what kind of materials to use to fix it.
Reply:I suggest that if I were welding it (glad i don't have to ) i would do it inside a small tent -IT would be tented . you won't be in the tent . you look through a clear small window ,( kinda like a small sand blast cabinet ) like they did at Mare Island, when they welded small TITANIUM  stuff. the tent was inerted,with argon, with a constant flow (about5cu.ft. /hr. & the torch only needed about 5cu.ft/hr , also . But, in this case it MIGHT indicate helium , instead , i don't know .I am guessing that some welding supply might be able to order you some Magnesium filler rod for the job. I doubt that many will stock that stuffLast edited by Roy Hodges; 05-29-2006 at 10:03 PM.
Reply:Mag is difficult to weld.  I recommend using helium, although it is not a requirement.  Cleanliness is the key.  With an engine case, you will have what amounts to metal that is impregnated with oil.  Your going to have to get that out.  Acetone will work well.  I would soak the case in a degreasing bath.  Mag should be welded with AC and a pure tungsten electrode.  A good filler rod is AZ101. When you weld it, your electrode will need to actually be in the puddle.  Because of the flammability of mag, make very sure there are no shavings anywhere near where you will be welding as they will burn first.  My best advice to you is if you have never welded mag, find a shop that has and let them do it.  Not to criticize you, but with little or no experience in this, you will probably just trash your case.
Reply:Here's a link I just found. Hope it helps.http://www.key-to-metals.com/Article35.htm
Reply:Your bike would be a magnesium alloy.  Many alloys can be TIG welded with the proper rod and conventional shielding.  As the percentage of magnesium goes up then there are problems and the job has to be done in a glove box.  This is not a repair for a regular welding shop.  You need to find someone who specializes in such repairs.  Locally at a nearby airport there is one outfit that repairs helicopter gearboxes.  An outfit like that would have the procedure down to a tee.
Reply:Hello, Your bike likely has an aluminum alloy, not a magnesium alloy crankcase. I've been doing motorcycle repairs and related stuff for a long time and few bikes, other than factory road racers have ever been built with pure magnesium or even mag. alloy crankcases. In fact, the only ones I can think of were possibly some of the early British Manx Nortons and AJS single and twin cylinder racers. I think that Harley did make some WR flathead racers with magnesium crankcases in the 1940's and 50's, but short of these, there aren't many. That said, if you do attempt to weld the case, given the size of the holes I am visualizing, I predict dire results unless done properly. First, the engine will have to be completely stripped and throroughly cleaned out of all oil and debris. It just cannot be done while assembled. Additionally, negative results may be had if the cases warp. In an attempt to avoid this, it might be necessary to partially reassemble them before striking an arc. Also pre-heating will be necessary unless you repair it with MIG, an unpleasant task assuming that I am wrong and you do have some sort of magnesium. Lastly, unless you are quite certain of the makeup of the metal, you will have a difficult time finding a proper filler rod and metal for the holes.If I sound negative, I guess I am. Most bikers, faced with a similar situation would be seeking another engine or set of crankcases. In Harleys for example, with which I am most familiar, it's more likely than not that the cases will get tossed when badly broken since a quick cost-benefit analysis would argue for replacement. I wish you luck on this.P.S. That's a great link to Key to Metals provided above by Orphan68.Last edited by gnm109; 05-29-2006 at 11:26 PM.
Reply:Originally Posted by bobthebikerwell, this is interesting, but doesnt help me much on finding out what kind of materials to use to fix it.
Reply:Well, since I cant figure it out, I'm just selling the whole thing on ebay.
Reply:Why not buy a new case?  They're only $1300.  That's probably not much more than you'd have to pay someone to weld the magnesium.
Reply:I played witha block of mag once.  Running straight argon.   Welds like alum.  Infact I dint know it was mag till later.  First semester of welding school and weld instructor gave me this shiny silver block, while I was welding aluminum parts and said, here weld this up for me.  It dint take the rod, but he told me to bury the tungsten, funny thing no inclusions...just wicked penetration.  Its good stuff.  Dont let it catch fire though.  Best to add up the post flow a pinchIF it Catches...Let it Burn
Reply:Originally Posted by 76GMC1500Why not buy a new case?  They're only $1300.  That's probably not much more than you'd have to pay someone to weld the magnesium.
Reply:Originally Posted by bobthebikerWell, since I cant figure it out, I'm just selling the whole thing on ebay.