Subject: Re: Mg Welding

From: T Lipton <[email-masked]>
Date: 5 Dec 1996 02:32:02 GMT

[email-masked] wrote:
>
> I have a need to TIG weld magnesium castings, specifically VW engine cases,
> and have not found much on the subject in my references. 
> 
>
> John,

  Tig welding Magnesium is no more difficult than welding Aluminum.
I have noticed a general trend in this news group about the hazards of
Magnesium melting and welding. I have Tig welded Mag concrete finishing
tools and motorcycle cases and brake backing plates without as much as a hint
of a problem. The flammability hazard of Magnesium is highly overrated.
  The hazards of magnesium come from finely divided particles, like dust
and chips of magnesium, which admitidly are quite flammable. Clean up the dust after you prep the weld and you should 
have no problem. 
 I am not sure what cast alloy VW cases are made from so I cannot recommend
a filler rod. A common cast alloy of mag is AZ91E and AZ91C. Talk to the local
VW engine builders and they can problably help you. Argon or Helium can be used for
Tig welding magnesium. 
For additional information on the subject you can look in Joining Magnesium by the 
Dow metal products company, The welding handbook from the American welding society.

  TML

---

From: "Ray F. Abadie" <[email-masked]>
Date: 2 Dec 1996 04:36:03 GMT

John,

By all means wait! I hope someone here has the info but as I recall
magnesium burns readily and is a very, very NASTY fire. I remember seeing a
car (Porsche 914 I believe) that had been completely encased in foam after
an engine fire yet you could see the engine block glowing through the foam.

How about it guys? Can this be done safely?

Ray

[email-masked] wrote in article <[email-masked]>...
> and have not found much on the subject in my references. Without knowing
the
> alloy which filler metal would work? Preheat or postheat necessary? Is it
> acceptable to weld Al plate to Mg castings? Which rod would be used in
this
> case?
> Thanks,
> John Caffrey
****************************************************************************
***
> *  John Caffrey                         *      Protoform Formula Vee     
    *
> *  Engineering Technician               *      Rotus/Ford Super Seven    
    *
> *  Dept. of Chemical Engineering        *                                
    *
> *  Lehigh University, Bethlehem, PA     *                                
    *
****************************************************************************
***

---

From: [email-masked]
Date: 11 Dec 1996 00:20:45 GMT

Depends....If you don't know the alloy, try 4043 aluminum first. As I
recall, the aircooled VW engines are high in magnesium and silicon. If the
castings are used, I tend to think your biggest problem will be dross
(junk and crap and goo and garbage in the weld). Preheating to cook it out
helps, or welding and chipping the weld out helps. Do it again till you
get a clean weld. I wouldn't worry much about porosity if it occurs. I've
done some flanges on VW cases.

Distortion can be a problem. It depends on what and where you're welding
on the casting. Preheat can help this also. 

Call Alcotech. These folks make lots of different rods and will help you
pick an alloy. You can e-mail me at [email-masked]