I've tried a bunch of different techniques like letting them sit on the table for a while, and many other things, but I've never had one turn out to be work hardened without at least 3-4 times through production and retentioning after each round. You can leave them on the table as long as you want I guess, but when I'm making screens, I don't have that luxury and I bring one up to about 5 newtons over the manu's recommended highest level and then tighten the rollers, let it sit for 5 minutes, then take it back up to the first tension level, tighten everything and then put it in production. I've let them sit around with the wrenches on and under pressure overnight without any noticeable difference in them becoming work hardened any faster, Sam is lucky. Some mesh relaxes more than others, mesh count and brands differ quite a bit in how much tension they lose between tensioning and how fast they stabilize, well, that's been my experience, others have obviously gotten different and better results.
When I have more time, I'll post about some of the brands that I've had better luck with elongation.
