I have a set of magnesium alloy forks that require welding.

Both bottom lugs are snapped for holding the spindle.

The plan is to build up one side with fresh metal and re-drill.

My work place is capable of the welding, but the welder requires

what type of magnesium alloy rod to use. He thinks a 30% rod, but would like verification

Can anyone please help.

I have done very limited Mag welding, but all I did was ask for Mag rod's and used what they gave me.

I will call a buddy of mine tonight that does that type of thing regularly (Lincoln Welding Motorsports) and ask what his reccomendation is.

As far as I know the only place to buy mag welding rods is Kent Foundaries,I bought a packet about 15 yrs. ago. They cost then

If you get stuck for the correct rods try Sifbronze Magnesium No:23 it comes in 3.2mm rods and you can buy them in 1kg packets. I've used them many times welding castings etc.

Good Luck

Dohhhhh,,, sorry, forgot last night, sat and watched a music performance by 1,2,3,4 and 5th graders.....

Will call tonight.

Ok, Bobby said there were basicly 2 types rod used, kind of corresponding to the 4043 and 5056 One is basicly more ductile and weaker and the other is the opposite. They were a 92 and a 61

I looked in my bin and what I have is AZ92A and is a Welco.

I looked around and found this

http://www.jwharris.com/welref/techguide/alloy_for_mag/gtaw/

Short version of the discussion is this

Make certain that they are actually Mag, Mag forks are rather unusual and would be something special, make sure you have done the Vinegar test. (drop of vinegar on clean weld prepared surface (sanded / blasted no oxidation) bubbles it is Mag, sits like a drop of water aluminum. Mag generally does not have the properties to make good fork legs.

He would choose the more ductile rod, not sure which number that was at the moment. As I look at their chart though, only the 92 shows for the cast alloys, and I am not sure, but I do not believe those would be wrought, I think a lower fork leg would just be a straight casting...

Add extra material, the original broke, and with the welding process they are dropping a % of strength, so you need to proportianly increase the strength or mass or design of the part to compensate. 30 to 40 % was round numbers but he was not positive on that, the number comes from Aluminum.

Stress cracking as the weld area runs out of the gas envelope is always a problem. If you can, find a way to weld on a steady preheated surface such as a hotplate etc. The extreme cooling action will often get you.

That one would be a tricky one at best, and you need to make sure you have everything working in your favor before you start.

Hope that helps.

Looking at the package I have something else hit me, it is one of the few rods that you buy by the ounce instead of the pound. Yep, bring money.....

If it was mine, it would be the 92 (and I assume you guys use the same system but may not) It is an American Welding Society standard so maybe you folks use some different grades.

What caused these things to shear in the first place?

Edited December 15, 200520 yr by Alan Bechard

Thank you all for the help.

Have ordered sifbronze No23 rods today.

Both fork legs are broken at spindle clamp, by previous owner.

I assume enthuisiasm got the better of ability

Will get rods next week and see how it goes.