Clean both surfaces with solvent to get all old sticky, oils and dirt removed. Scuff the pad on the bottom with at least 80 grit. Clean it again and thoroughly dry it.
Apply copious amount of Marine Goop to the bottom of the pad. Lay pad down and add a few big bricks or other weight for 8 to 12 hours. Trim off any goop that has squished out.
Insayn, is the marine goop the same as automotive goop, or shoe goo? I think they are about all the same stuff. I use shoe goo for so much stuff, it cracks me up.
Essentially the same stuff. Marine GOOP has better UV stabilizers. I use A LOT of the Marine GOOP for my fishing kayak hardware installs. This stuff rocks!
Last 5 years I've messed up many things trying to glue. Found this site and yes "Goop" is the stuff to use. Elmers has some company in the glue drawer at my house last couple years. Good site for things that need different type of glue. http://www.thistothat.com/cgi-bin/glue.cgi?lang=en&this=Rubber&that=Metal