Originally Posted by ME 109
Thing is, the solder diametre needs to be close to the ideal shim thickness so as to not bow the tranny cover when the screws are torqued down.
yeah, that was my thought too. I was thinking of trying to make a plait or twist of thinner soldering wire first, and try to use that to determine where your ballpark is, then see if you can get a thicker strand of solder that is just too thick. I was imagining it taking a few tries to raise (or destroy) the confidence level.
For putty, you could try that 'knead it' epoxy stuff (often used for metal repair). It is about the consistency you want- only problem is that the couple of tubes I've owned have all set-up pretty quickly. There must be a slow cure version?