I was attempting to buy some Plexiglas cement a few days ago. Some Weldon #3 to be exact. Its a bunch of solvents and some PMMA monomer and solvent-welds pieces of Plexiglas into large single pieces of Plexiglas. Its water-thin, and gets pulled into the space between the pieces via capillary action. Wait a minute, and its solid enough to handle.
Unfortunately, Maryland has banned the stuff. The recommended alternative is Weldon #42, a two part epoxy.
Epoxy is no substitute for solvent welding. Its a joke, except that apparently we are supposed to take it seriously. Plexiglas is pretty non-porus, there isn't anything for the epoxy to hang onto. It'll fall apart, and if its an aquarium, it'll be a serious mess.
Why are we as a country so terrified of the right tool? Knives are sharp, you can hurt yourself with them. But that sharpness is what makes them useful. Insecticides are poisonous. Thats what makes them useful. Some solvents are volatile. If you're using them for cement thats what makes them useful.
Without chemistry sets, there will be no chemists. A first grader will be impressed with vinegar and baking soda, a middle schooler will be bored. And then all of a sudden in college, freshmen are expected to be able to handle 98% sulfuric acid. Start with vinegar. Move on the glacial acetic acid. Don't drink it. (its not hard.)
Without fireworks there will be no rocket scientists. Goddard was able to buy liquid oxygen, and invented the liquid fueled rocket. I can't even buy liquid nitrogen now a days. (It makes good ice-cream.) And then if a kid decides they are going to break the rules, they aren't going to bother with the small stuff (if you're breaking big rules, might as well go all in). And then, since they have no experience, no sense of scale, they are going to blow their head off.
Powerful tools are dangerous. Its what makes them powerful. We should respect them. But that is not being afraid of them. If we are afraid of them, then we won't use them. And if we don't use them, we won't accomplish anything. And after that, all thats left is rotting on a couch watching TV (But don't sit too close!).