Thanks. BTW - I love the "this saw has been dicked with" sign - can you share the story behind it?
Magnesium Case Repair - Weld, JB Weld, or ???
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Thanks. BTW - I love the "this saw has been dicked with" sign - can you share the story behind it?
Wrong
So you've backpedaled from ZERO success to now not being as strong as original on certain Stihl parts. Didn't realize we were only talking exclusively Stihl Contra where the handle attaches to the case, so no, zero experience there. But still you want some sort of testimonial that all my repairs work perfectly over some unspecified time? And to bother explaining my methods while you already claim to have experience over 50 years with this? LOL!
My most common repairs are cracked clutch covers, I've done at least a few dozen of them (including Stihl) and so far no weld failures. Various crank case repairs are probably next in frequency and at least the ones I've done for myself have been fine. 2 or 10 or 50 years from now, who knows...
I just did a spider web cracked bar mount area mess of a 395 crank case for someone. Had I realized just how many cracks I was going to end up chasing I wouldn't have even started it but became a challenge of sorts. Ended up an overly complicated job that I didn't have a high level of confidence in the finished result, will be interesting to see if it holds up, assuming it gets used.
Cast mag welds more or less the same way as doing aluminum but without the puddled material having such a tenancy to jump onto the electrode. Meaning you can bury it in the puddle without particular issue, so much more forgiving of unsteady hands. Filler rod I use is az92a.
Here's an example that was almost broken in half, normally wouldn't have bothered with such a common part but was just practicing on it. Outside gets blended in for cosmetics, inside stays with the beads to add strength
Here are some pics -
Stihl Contra case half.
Stihl Contra case half.
And the other half...
Small crack indicated by the tip of the metal pick.
Small crack indicated by the tip of the metal pick.
First picture includes one more Contra (in the box), a few 07's, an 070, a Landoni, and a Dolmar. Some of these will need some repairs here and there.
Second picture includes a few 051's, an 075 and an 076. Some will need some work but that comes later.
And the third picture is a Contra cylinder - exhaust stud got torn out. Figure the best repair would be filling it in and then drilling and tapping a new hole. Doesn't need to be pretty.
Lots more in the garage and I think I have three more saws on the way from Sweden, but you get the picture (literally!).
Second picture includes a few 051's, an 075 and an 076. Some will need some work but that comes later.
And the third picture is a Contra cylinder - exhaust stud got torn out. Figure the best repair would be filling it in and then drilling and tapping a new hole. Doesn't need to be pretty.
Lots more in the garage and I think I have three more saws on the way from Sweden, but you get the picture (literally!).
srcarr52
We can't stop here, this is bat country.
Those case cracks look to be easy repairs. These older saws weld up much nicer than new ones, back then they didn't go cheap on the alloy and the base metal is much more pure. JB weld isn't going to be any help on those cracks.
The cylinder is aluminum. I usually ditch cut them and weld in solid, then drill and tap the hole. Since you have around 270deg of material left and the full circle behind, I would say you could get away with a carefully inserted time-sert.
The AHP welder you are looking at does get great reviews. Weld.com speaks highly of them. I was thinking about getting one myself for a smaller more precise machine then the behemoth I have now.
The cylinder is aluminum. I usually ditch cut them and weld in solid, then drill and tap the hole. Since you have around 270deg of material left and the full circle behind, I would say you could get away with a carefully inserted time-sert.
The AHP welder you are looking at does get great reviews. Weld.com speaks highly of them. I was thinking about getting one myself for a smaller more precise machine then the behemoth I have now.
ChoppyChoppy
Tree Freak
I'm surprise a $700 TIG gets any happy customers. My TIG was about $5000. Miller 250DX with water cooler.
srcarr52
We can't stop here, this is bat country.
My tig welder is from the mid 80's. I wouldn't want to reply on it for a job shop but it will make decent welds in a skilled hand for the occasional use.
The hardest part of welding mag is making sure it is clean! Now you going cast mag which is another beast in itself(im sure the other welders can agree with me on this). I currently use a mill r Dynasty 350. It's not your average home owner tig set up but it is well worth the money. A lot of these guys have done a job like this and has great input. The only thing I can add is to pre heat the material to at least 90-100 degrees(makes your start a lot easier and prevents cold cracks at the beginning of your root) and to clean it. When you think you have it clean enough. Clean it again. Good luck!
Appreciate all the input, fellas. I'll see about getting someone to TIG it locally.
+1. big cold fat ones where looks don't matter, then dig em out on good side, and nice hot fill to finish.
Have never had jb-weld last on any repair I have made. Had a 056 handle snap and carried it to tig man and he said he could do it but it had to be cleaned completely. He repaired and you can not even tell after repainting.
This might be your lucky day! Have I got some excellent practice for you. Look at this thread and let me know how to prep it and where to send it. So glad I found this thread.
https://www.arboristsite.com/commun...ime-from-a-181-reveals-cracks-in-case.317319/
This is a great website with great members.
If it was a super rare part I'd certainly consider fixing it but since it's a pretty common item and the crack is in a high stress area known for failure on this particular saw, IMHO you'd be better off replacing it.
srcarr52
We can't stop here, this is bat country.
I wouldn't bother with that, too much damage. 181 cases are easy enough to get.
