Can one fix cracked magnesium?

Hello again!

I am back with yet another question.

I have a BMW R1200GS motorcycle which i ride daily for everykind of purpose from commuting Between places A & B, to drifting on a track or dirtstretch etc.

Last week i was cleaning up my garage when i bumped on a magnesium engine head cover i had replaced last year.

The damn thing was pretty expensive to get replaced.

I gazed at it just to remember there were no signs of a fall what so ever!

It looks brand new except for that hairline crack that can be seen from the inside. - That caused oil to leak onto the ignition system of the one (of two for each cylinder) spark plug causing it ti missfire and cause a disturbed engine operation...

Naturally the question that rises is how one can fix that.

I had a look around to find that you can weld magnesium. However i figured out that this is not a job that can be done by the usual fix it all type of person.

Do you know any better?
Any chance you knew of a resin to do the job?
The cylinder head cover gets quite hot, not like the engine, but when its fully warm you cannot have your hand on it for too long.

If you can't get it welded you can take the cover off, clean it really good, then put "PRO-SEAL" on the inside of the cover on the cracked area. This pro-seal is used by aircraft manufactures to seal fuel tanks. it is very good stuff and can be found online through some of the aiviation stores. it is also heat and oil resistint and flexible, it WILL NOT come off! plus the MIlitary uses it, what does that say.
www.aircraftspruce.com...

[edit on 23-1-2009 by 38181]

One guy mentioned using superglue, but i don t think that will last long in the environment of an engine.

I dont think you really can.

Once cracked its done. Any attempts to weld the crack shut will result in a intense but spectacular fire.

reply to post by 38181

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Thanks!

I think your solution is the best i have come accross.

I haven t checked it out yet, but i will right away.

I hope it can take the associated expansion-contraction stresses.

I will propably have a go at it, once i check it out!

Be well.

You could take it to a welder who uses tungsten inert gas (TIG) tig welder, and let them have a look or call a shop

[edit on 23/1/2009 by Sauron]

Keep us informed about this one.

I'm skeptical that anything can be done for it.

Certainly, the forces found inside a fuel tank or a fuselage are not nearly what one would find inside a cylinder head.

I think I'd talk with a BMW service center before I invested any money into some avant garde repair work.

Pro-Seal AKA "Type B-2" will do the job, guaranteed. The pressure under a valve cover is not enough to affect the pro-seal or else everyones engines would leak like a sive with the Cork gaskets most engines use, hense PVC valve. Again aircraft manufactures not only use it in presurized fuel tanks under extreme conditions but use it on pressurized airframes and gap seals ,both on commercial aircraft and Military Fighters, I know. And since it has a MIL spec. i rest my case. Try it you cant break anything!



[edit on 24-1-2009 by 38181]

Surely this part is not pure Magnesium. It may be Aluminum alloyed with Magnesium to give it certain metallurgical properties.

A TIG welder would do best as it is the most precise welding with the most variety of filler materials available. Since it is probably aluminum, I wouldn't see a problem welding it.

Commercial grade aluminum alloys

Yes this is unlikely to be pure magnesium, more of a combination of aluminium and magnesium alloys, i am a tig welder and i would be able to do this type of repair and have done some like described,

super glue does not hold under heat but i like the sound of that PRO SEAL that sounds like a good option if you cant get it TIG welded,

TIG's are amazing they can weld just about any metal or alloy and the quality of the weld is excellent