So I'm building the 1:14th scale Boyce Nike Hercules with all its 3D printed parts and I've been using the Acetone Vapor Exposure method to help with sanding the parts. That is where you expose the parts to the vapors of acetone for 40 minutes to an hour and it melts the part just enough to give it a smooth shinny finish. Well I left a part, the most important part (the transition that ties the four booster tubes to the upper stage), in the vapor container for over four hours. Fortunately the part was big and thick enough to have survived, but I had already attached the 3D Printed launch lug to the piece before I put it in. It was nice and perky when it went in, and came out looking like the old lady suit in "Something About Mary"! I'm lucky I didn't mess it up even more because I couldn't leave it alone and the part is very soft and pliable for a long time after the exposure.
Fixable, but lesson learned. Use timers and alarms when doing Acetone Vapor Sanding. Something like one alarm at 40 minutes with a backup one at one hour.