The only guaranteed adhesive for exterior use, IMO, is a cement-based adhesive. I use it for adhesive AND grout. Weldbond won't hold up - re-hydrates when wet. I've heard negative things about the hardware store construction adhesives. For me, the ONLY thing I use outside is thinset w/the polymer additives. I'm too lazy to use the admixtures, is the reason I buy Mapei's products that have it already.

Weldbond is the best for outdoor mosaics. Unless you plan to leave your project groutless. Once you grout, water can't get under your glue (your glass is sealed by your grout).

You might want to check this out. I wouldn't EVER use weldbond for outside. the least bit of moisture will do you in

Here is a link that might be useful: adhesives

Oh rats, BETTYC - I forgot to mention that my only outside disaster was a large terra cotta pot I mosaiced for exterior use. It was one of my first exterior projects, and I sealed the pot w/glue and water. All the tesserae fell off this past winter. On the other pots I didn't seal, and they're still standing well.

Only thinset mortar like slow say's for outside.

OK, I think the Mapei will be nicer than the yellowish stuff - not quite sure what the other stuff is, and it is kind of hard to clean up.
I like knowing what is in the materials I use with children.

Thanks!

Just adding my 2¢ for the thinset. I'm relatively new to mosaics, but I've used thinset almost exclusively on my projects (save one GE II bowling ball), and I wouldn't use anything else now. Especially on stepping stones, where the thinset will "marry" very nicely with it.
Good luck on the camp!

I too have used Weldbond outside, I'm in Texas, and I have not had a problem. Once it is grouted and sealed well.
But again, I am in Texas.
I am using thinset lately, and after getting the hang of it, I like it.
That's my story and I'm sticking to it.

Does Thinset go by any other name? I'm having a hard time finding some of the adhesives that I read about. I just came back from Home Depot & couldn't find it. I asked for help & they said they would send someone from that dept to help me, but I finally gave up waiting for someone to show up.
Herself

HERSELF: Thinset is a cement-based adhesive in powder form. Some brands have the polymer admixture added, and other don't. That's the reason I use Mapei Polymer modified mortar (thinset). Some hardware stores carry thinset w/o the admixture. However, you can buy the liquid admixture and add it to your thinset, if you don't have access to Mapei brand. Lowes carries Mapei. Never shop at Home D, just for that reason - nobody around to help w/questions.

have any of you ever used the premixed thinset? how does it measure up to mixing it yourself

Slowmedown: Thanks for the info! I'm want to try some different adhesives from what I have been using. I'll have to go over to Lowe's & pick some up. (The only reason I went to Home Depot was I got a $30 dollar gift certificate for Mother's Day!) LOL!

Herself

I use the pre-mixed thinset all the time. Mapei Type 2 says for outside, but is hard to find so I use whatever I find. I have had no trouble with it. Try is for the kids and the stones...

I went to Lowes & they didn't have the Mapei. Our Lowe's doesn't carry it. They send me to a tile flooring store. He didn't have it but at least knew what it was & recomended another type that he uses. He only had 50 LB bags, but sold me a 1/2 bag so I could try it. It's not cheap it goes for $50 dollars a bag. I wonder if it would be cheaper to buy the regular thinset & add the polymer admixture myself. Anyway I can't wait to start my new project tomorrow!

I know it's expensive, HER, but I like it so much, I buy it anyway. I buy it by 50 lbs. at $19.90 plus tax. You can buy any thinset and add your polymer admixture.

50lbs for 19.90 isn't bad, Slow. This stuff I got was $50 dollars for 50lbs, and I brought a 1/2 bag for $25. I'll use this stuff, and try to find the mapei later.

Is it ok with frost? - maybe epoxy would be best if frost could be a problem - but that is very expensive,

Cement-based adhesive holds even in frost. It's the tesserae that needs to be frost resistant, TOBY. Haven't seen you b/f. Welcome.