Thought I would share my experience today with some Aqua 20oz Tumb’s which I hate BTW.
I did half the order yesterday. The shop was 78 degrees in it. Clean looking engraving on them.
Had a cold front come through last night, and the shop was 58. The tumb’s were very very cool, and really cold to the touch. First tumb engraved but he leading letter didn’t quite get all the powder coat off. I think the rest of it engraved ok, because the laser was heating it up as the tumb rollled.
I took a heat gun and warmed up the 2 and 3, and so on. Clean engrave all the way across. It was a bad day for the stink bug that found his way into my heat gun though.
Just food for thought.