Many thanks, was thinking of trying silver solder, but unsure of the metallurgy. Good call on the JB weld, but the previous owner had tried to patch the hole with JB weld which is why it had been leaking. push comes to shove I can try lining the inside of the weld in the oil tank with some JB weld o...

I've an interesting project. Magnesium chainsaw crankcase with a hole through the front of it. Was able to get most of it patched up with weld(AZ92A filler), but have a pinhole on one side of the repair. The hole is in the front of a cast magnesium bar and chain oil tank, and I can only take so much...