Hi, ANS: Thinset is a great adhesive. If your cup half doesn't adhere, since there is little surface in which to use thinset, you can also use GE II and use enough that it squishes up to fill the void places a bit. It is another good adhesive, but I've stopped using it except for rare objects, and always have plenty of ventilation. It is very toxic. You have a cute idea going, so good luck and keep us posted. Don't know what's happened to the forum - everyone seems very busy lately.

I did as you said with the thinset, squishing it up to fill voids where I could. Checking it today, it feels fairly firm, so I think it will be fine after all, especially as it's decorative & not functional.

I really like thinset & try to avoid the smelly adhesives too. I started wondering how people attach 'chunkier' pieces as I'd like to do more projects incorporating found objects. Does anyone use mesh somehow in combination with an adhesive for strength? Or has anyone had something fall off & know why?

Thanks Slow for responding. I'll keep working on this when I can but, unlike you, I am so slowwwwwww!

I have stuff fall off all the time, but it is usually because my clumsy seft bumped it. The thinset will hold great. A lot of times for outdoor work and on my backsplash I used Bond-O like body shops use. I got mine at an auto supply store and it sets up in 5 min and they you can not knock stuff off with a chisel. Good luck, great start

Thanks flagtruck! If I was going to keep it, I'd use this as a test project and wiggle it a bunch, but I'm giving this to my friend, so it'd be nice if it lasted a day or two :)
Here's the work from today; thought I'd try gluing a string of beads as a border for the mirror:

Started background today:

Beautiful work. Love the beads. Your Shamrocks are perfectly cut!!!