Liner in my pool has a few spots that come loose every year. I've always put it back by hand except for one year in the spring when it was cool. Used a hair dryer with a GFI cord plugged into a GFI outlet. Worked with my hands in the heat... if my hands got too warm then the liner was probably getting too warm. Would also like some feedback on liner lock from others. I've used pieces in the past to address trouble spots but the pieces pop out. Liner continues to pop out all year also in new spots. I have an old (20 yr+-) Buster Crabbe IG with polymer walls and they just dont hold the bead. This year I'm getting a whole roll and locking the whole perimeter. If that doesn't work I may have to install new aftermarket coping and reset the liner.