The problem with plexiglass

In addition to keeping ants I also keep true spiders, tarantulas, mantids, isopods and the occasional beetle.  I am fairly new to all of it, and apparently still have quite a lot to learn.  The dog is the only thing straightforward.  She is pretty much self-keeping really.  She bugs me when she wants to be fed or let out, and barks to come in.  She reminds me in the evening that she needs some exercise, by prodding me with her nose until I give in.  But the rest of the creatures are not quite so self-supporting.  I have two plexiglass cages, one I bought used off kijiji that is clearly a tarantula enclosure, with a lock, the other I made myself.  The second was really is quite sharp looking.  Or it was, until the warping began.  The bought one has warped so that it really doesn't close very well, but I thought it was still pretty secure. However, Fred, the Carolina wolf spider, Hogna carolinensis, somehow managed to get out of it last night.

Fred, the missing arachnid

He is a really big dude, fully mature, and I just don't know how he managed to squeeze his butt out, especially since he cannot climb smooth surfaces.  Nonetheless he is gone as of this morning, and part of my work day is going to be taking up with trying to find him, before someone else in my household does and is not very pleased with me!

The other cage, the one I made, has an orb web spider in it, who is also a bit of an escape artist, but lately she is an eating machine and doesn't seem to have any interest in leaving.  Plus when she does escape she always goes to exactly the same place (3X now, out of 3 different containers), the top of the bookshelf, where she makes a web that won't catch anything (except maybe Fred now).

Anyway, I am very disappointed in how much plexiglass warps, and I won't be buying or making any more cages out of it for that reason!

Update:  Fred has apparently caught a flight back to Carolina, because he is not in my house anywhere!