Nice mosaics! They look familiar. Are you in CMA?
I know many books and teachers use Weldbond, but it is not waterproof at all. Even high humidity can cause it to turn white and soften up again. One person did a huge lifesize bust for a garden. It was a commission and she was paid very well. After less than a year, the pieces all started slipping off the bust. It might be fine for an area under a patio roof where it only gets wet occasionally. In a wet area or freezing area, it's not really safe to use outdoors.
https://search.yahoo.com/yhs/s...
