If you don't get any tips here, try the "Garden Junk" forum.

Here is a link that might be useful: Garden Junk

Maybe using a hot glue gun would work or Gorilla Glue. I`ve used that stuff on a lot of things.

I tried hot glue but it pops off after you add water. Also some thing that sets quickly. And that can withstand outside conditions.

Try Weldbond, I use it for mosaic tiles and it dries clear. Should form a good bond for outdoor/wet conditions. I have bought it at a stained glass supplier and my local ACE hardware. I'm sure the big box stores have it too. Good Luck!

Try using silicone. You can purchase it at your local pet store. It is non-toxic. Used for sealing fish tanks. This is what holds the tanks together.