I have on m y workbench an older Dolmar that has been run hard and put away wet numerous times that I have not really gotten into yet that has of all things a cracked front case and it's peeing bar oil from the crack. I presume the crack isn't impacting the crank or the crank seals (don't know yet as it's not taken apart but can I weld up the case crack and have the saw be viable again? Keep in mind that we are very accomplished TIG welders and have the proper equipment and skill set for certified TIG welding in exotic alloys and do it every day. I just am not sure about this old saw and it's case crack yet as it's not taken apart at all. That is next on the agenda, that and getting parts for it. I have a feeling it has at least piston and ring issues additionally. It has many hours on it, basically run hard. I'll know when I pull the muffler and have a look inside and see the 'bad news'...
Just curious about something....
- Thread starter Sidecarflip
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I guess the issue is, is it die cast aluminum or die cast magnesium. The issue with magnesium is it reacts with oxygen when heated, not that the atmosphere around the weld area will be because that will be inert gas. Just curious about once it's welded and cooling, if the impacted area will self combust. We don't weld mag as a rule so it's kind of a grey area with us. Mag is funny stuff to deal with as a rule and I presume (but need clarification) whether 100% Argon is the correct shielding gas or not and what about filler rod or if any or not?
Kind of uncharted territory for us so any and all input would be appreciated, just like the weld parameters, should it be AC pulsed or not and what Tungsten is applicable.
When I get it apart, I'll know how bad it is or if it can actually be fixed. Presently, it's a frigg'in mess of old gummy sawdust and crud that I will have to remove before anything. Pressure washer time first and a liberal application of ZEP purple power.
I'd post a picture of it but it's real ugly presently.
Kind of uncharted territory for us so any and all input would be appreciated, just like the weld parameters, should it be AC pulsed or not and what Tungsten is applicable.
When I get it apart, I'll know how bad it is or if it can actually be fixed. Presently, it's a frigg'in mess of old gummy sawdust and crud that I will have to remove before anything. Pressure washer time first and a liberal application of ZEP purple power.
I'd post a picture of it but it's real ugly presently.
Video Scarr did on welding mag might help too. Info in later part.
What kind of old Dolmar?
My step dad welded up the magnesium brake pedal bracket on my '87 F-350 using the Argon he already had for his TIG machine. Toughest part was finding filler. He did turn up the Pre and Post flow times a little. Solid parts aren't as risky, but filings are at a much greater risk of creating A self sustaining reaction. So clean and then make sure the area is clear before lighting the torch.
Ensure you know its magnesium or alluminium prior to attempting any welding . A few drops of pure vinegar on the degreased casing will bubble up if magnesium . AZ 61 or AZ 101 tig filler rod or #23 wire is preferred for this weld on magnesium alloys . Ensure both surfaces are clean of any oil , grease or debris . P.S. fumes & vapous & mists from magnesium welding is highly toxic . Positive pressure helmet or fume hood to ensure adequate general ventilation is advised .
Dont have to worry about me welding jack crap. I chicken crap my ER welds on steel.
Dont have to worry about me welding jack crap. I chicken crap my ER welds on steel.
Sorry RCR just file it under a point of general trivia lol.
Disassemble the saw completely. Uber-clean the case half that is cracked with solvent to remove all oil. Follow other’s instructions here
That answered most all my questions other than pre and post flow and we primarily use 100% argon anyway. I can use 75% Argon and 25% helium but that is rare so I don't keep a large bottle of it around. I keep a small bottle just in case. I'll have to get some mag filler rod however.
I was planning on cleaning it with the PW and then using Acetone followed by carbon tet. I have that by the way, just don't tell anyone...lolDisassemble the saw completely. Uber-clean the case half that is cracked with solvent to remove all oil. Follow other’s instructions here
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