Stihl crank case repair(welding)?!?!?!

[Teddy.Scout]

I have been pretty lucky with the spot welds and repairs that I have done on crank cases! But like always, I am going to try to push it!
I have been assuming that when I spot weld or tack weld the case, I have been treating it like soft aluminum!?!?

Is there any thing you guys recommend when I try to do some major modifications(structural) repairs! It may be a waste of time, but I am atleast having fun.

Thanks guys!

 

[ironman_gq]

As far as I know its like welding any aluminum casting. preheat and make sure it is very clean or your weld is not going to go well. If your tig machine can do it turn up the frequency to concentrate the arc and get better penetration also adjust the AC balance for more penetration.

 

[oscar4883]

Is it a crack in the case that you are going to weld? If it is, I may have some info. Never welded mag though. I would make sure to practice on an old case if you have one to get your settings down. If there are bearings in the case make sure to ground as close to your work area as possible. Bearings don't like welding current LOL.

 

[ironman_gq]

Is it a crack in the case that you are going to weld? If it is, I may have some info. Never welded mag though. I would make sure to practice on an old case if you have one to get your settings down. If there are bearings in the case make sure to ground as close to your work area as possible. Bearings don't like welding current LOL.

Neither do shocks on off-road rigs

 

[Teddy.Scout]

As far as I know its like welding any aluminum casting. preheat and make sure it is very clean or your weld is not going to go well. If your tig machine can do it turn up the frequency to concentrate the arc and get better penetration also adjust the AC balance for more penetration.

Is it a crack in the case that you are going to weld? If it is, I may have some info. Never welded mag though. I would make sure to practice on an old case if you have one to get your settings down. If there are bearings in the case make sure to ground as close to your work area as possible. Bearings don't like welding current LOL.

Thanks guys!
I am working with bare cases, and am looking or trying to fix the basics(cracks, broke out screw holes and my OL'GIRL 026, that has a good chip off the front clutch side!!! I miss her!! LOL.
As for the grounding! I still remember a trouble call were I saw a tree crews crane tires on fire!!!

 

[oscar4883]

As far as cracks are concerned there are two basic mehtods of repair. One is to grind and feather the crack out and weld. Preferably grind in from both sides but I'm sure you have limited access and surface area. Or you can terminate the crack at drilled holes and grind out in between the holes and weld. The holes don't even need to be thru holes. A blind hole deeper than the crack should work well. Hope my poor explanation makes some sense.

 

[Teddy.Scout]

As far as cracks are concerned there are two basic mehtods of repair. One is to grind and feather the crack out and weld. Preferably grind in from both sides but I'm sure you have limited access and surface area. Or you can terminate the crack at drilled holes and grind out in between the holes and weld. The holes don't even need to be thru holes. A blind hole deeper than the crack should work well. Hope my poor explanation makes some sense.

Heck ya! I should have thought of that! But that is why I am asking you guys!!
That's what I do with cast that has a crack!(a crack is a crack! in any metal.)!!!!

Here's a pic of a clutch cover, this was a trail!
Look right below the black marker, the weld did not penetrate! I am not giving up!!!!!!!!!!!!!

 

[howellhandmade]

You can weld magnesium? I'll be dipped, I would have thought it would burn.

Jack

 

[Teddy.Scout]

I did burn it!
Only about half my weld was even some what kinda decent! Still needed a coat of JB and a good sanding to make it decent!! LOL

 

[pmbou]

careful welding magnesium

I never tried welding magnesium but it sounds like fun. If it sparks off it's white hot and bright as hell. Best put shield gas on both sides and weld outdoors. Good luck.

Holy crap, I just saw that you torched it and it worked. Good job. How did it go? How did it compare to aluminum?

 

[Teddy.Scout]

I wouldn't say it worked!
The weld only has one good spot!
Need to take what I learned and apply it to the whole weld!
I have a long way to go before I can say I did it!!

 

[SkippyKtm]

yah, Welding mag is tough- I've tried it twice with my TIG and got poor results both times. The first time the weld looked great, but as it cooled I could hear an ominous cracking sound, I should have pre and post heated it kinda like what you do for thin cast iron.

 

[Teddy.Scout]

PROOF!!!!!!!!!

That sound after I got done welding was like some one stepping on little X-mas lights!!!!!!!

Good point PRE heat and POST heat!!!!

 

[Boleclimber]

PROOF!!!!!!!!!

That sound after I got done welding was like some one stepping on little X-mas lights!!!!!!!

Good point PRE heat and POST heat!!!!

This may be a stupid comment but, did you use magnesium filler rod and clean the area to perfection?



I have welded a few husqvarna clutch covers with magnesium filler, no pre-heating and no after heating. The welds looked good and held.

I used an very clean aluminum cutter burr in a die grinder. I have found using a grinding disk or sand paper places too much crud in the welding area. I cleaned all oil residue off the off the entire clutch cover using break clean, then burr ground the crack, within minutes followed by welding . The magnesium crack was shiny bright, like a mirror before I welded.

I would never be able to weld the crack you have pictured with the grinding marks, it is way too dirty.

 

[oscar4883]

Never welded mag so take it for what its worth, but when welding cast pieces it may pay to peen the welds after welding. Like on cast iron repair for instance, a very light peening can help stop cracking. Apparently many here have not heard of the technique. I think it helps slighty relieve the welded area of stress by stretching the weld slightly as it begins to cool. A VERY light peening. That and cover the piece with a blanket or throw a leather apron or weld jacket over it to slow the cooling. Hope this helps your project. I have no info on the science of this, if that matters to you, but it is something every oldtimer I know does. Some sharp guys them old timers.:greenchainsaw:

 

[Teddy.Scout]

This may be a stupid comment but, did you use magnesium filler rod and clean the area to perfection?



I have welded a few husqvarna clutch covers with magnesium filler, no pre-heating and no after heating. The welds looked good and held.

I used an very clean aluminum cutter burr in a die grinder. I have found using a grinding disk or sand paper places too much crud in the welding area. I cleaned all oil residue off the off the entire clutch cover using break clean, then burr ground the crack, within minutes followed by welding . The magnesium crack was shiny bright, like a mirror before I welded.

I would never be able to weld the crack you have pictured with the grinding marks, it is way too dirty.

Ya! Clean is key! I will keep trying!

Never welded mag so take it for what its worth, but when welding cast pieces it may pay to peen the welds after welding. Like on cast iron repair for instance, a very light peening can help stop cracking. Apparently many here have not heard of the technique. I think it helps slighty relieve the welded area of stress by stretching the weld slightly as it begins to cool. A VERY light peening. That and cover the piece with a blanket or throw a leather apron or weld jacket over it to slow the cooling. Hope this helps your project. I have no info on the science of this, if that matters to you, but it is something every oldtimer I know does. Some sharp guys them old timers.:greenchainsaw:

I love them old timers!!!!!!!!!!!!!!!!!!!!!

 

[Winn R]

Would one of you guys who have run tig on magnesium give me a rod #?
Thanks

 

[ironman_gq]

Probably easiest to talk to you welding supplier

 

[Hddnis]

I've read that welding a part cleaned with break cleaner can produce a deadly gas. Several stories of this over the years in various publications.

Just to be safe I don't use break cleaner on an item to be welded and thought I'd pass it on to hopefully save someone grief.



Mr. HE

 

[ironman_gq]

As far as I know it's the red can or non-flammable variety that is especially dangerous