@HS- It's a type of solvent(the plexiglass places like maizeys sell it) called "Tensol No12".
Try get hold of Claratite. Maizey's should be able to get it, even though they actually get it from MR plastic I believe.
Then go to the TAP plastics website and watch their instructional video called
"How to glue Acrylic" 
If you cant find the bottle they use. Go to the pharmacy and buy yourself about 10 x 1mm Insulin injections and needles. There are a few out there and some work better than others, but its all trial and error. It will take a while to get used to using the needle. But once you get the hang of it you will never look back. I can build a square cage, including hasps, staples and hinges in about 5 min now once I have all the material cut and prepared.
Next Tip.. Go and buy a small "cooking" torch. The ones they use to melt the sugar when making Crème brûlée. The ones with a tiny intense flame. Now when you are done with your cage and it has dried nicely (about 2-3 hours) use the torch quickly around the edges. Not enough to set it alight and melt it. Just enough to soften the rough edges and make it look "glassy".