what glue for rubber to metal

I used the Gorilla construction adhesive to attach rubber panels behind bumper to deflect road spray from toad behind motorhome. This is the very best I have ever used. If you do not want it to fall off this is one you want to use. Becomes tacky in a few minutes but takes 24 hours to dry. Remains somewhat soft but will not peel away. I attached the rubber panels nearly 3 yrs ago and when traveling down the road they are under whatever wind pressure is underneath the coach when you rolling down the highway and they have never become detached. I purchased the Gorilla product in a caulk tube but I think you can buy in smaller amounts at Home Depot or any place home products for building material are sold.