I use 3-M double sided tape. Sticks great to both the mylar and the walls not to mention it gives a good cutting guide so the mylar doesn't rip up.

Have a good grow!:jointsmile:
Psycho4Bud Reviewed by Psycho4Bud on . HOW TO PUT UP MYLAR How did every body put up their mylar? I dont have a staple gun and the thumb tacks just rip the mylar. Rating: 5