Noticed after installing 1 1/2 PVC drain parts something I really didn't expect. Though I'd well hand-tightened the nuts, I found that when the dishwasher's hot water dumped into the disposer, the PVC pipes must have softened enough to allow the nuts to tighten a little more. I'm curious how stable these parts are over time. My hot water is at about 128 F right now. I've set it back down because I've seen suggestions that it be around 120 F. In any case, I really don't know that this issue wouldn't be seen at 120 degrees. Can anyone comment on the proper way to tighten these PVC parts or the long-term suitablity of them where hot water may be used?
Also - someone suggested using pipe joint compound on the threads and giving the nut a little nudge with a wrench. I have my doubts about both suggestions.