I may get some grief for this, but what about silicone?

I went cheap when I replaced my pad. Really cheap... try $11 "New" pad w/heat shield from PNP which thankfully someone had glued on very poorly (looks perfect and came off very easily). I used two tubes of cheapo walmart clear 100% silicone. Total cost less then $20. I did clean the surface very well before, and I removed the hood (changed actually). The pad has been on ~6 months and is very well secured.