What to Use to attach Plexi to Plastic????

[ensquire]

Wouldn't you know it. I went and had a piece of glass cut to fit. Came home to replace the plexiglass so I had to cut off last of the black plastic brace. One end wouldn't come apart and the other end only released after applying a lot of pressure. So I finished the trimming, added more epoxy, clamped it together. Went to it this morning and it is bonded. I have the glass as a backup if it fails, but maybe I got lucky and have solved this problem.

As for the two links, I was kinda wondering what fastening device would work in this environment. Nylon screws would be perfect.
Thanks for all the good advise and ideas, If there are any changes I will report them...