I'm really using LocTite Stick 'n' Seal Outdoor Adhesive. I LOVE this adhesive. It's a clear gel that is super versatile. The downside is you really need to clamp the two surfaces together for 24 hours. The upside is that you can glue just about anything to anything else.

This belongs in everyone's toolbox. And no, I'm not paid to say that - it really is that good of an adhesive!

http://www.loctiteproducts.com/p/6/31/cntct_osns/overview/Loctite-Stik'n-Seal-Outdoor-Adhesive.htm