Ideas for reinforcing Rody Rabbit tank

[pelicano]

I've previously had a Rody Rabbit tank, with the bars at the top meshed up, and some metal plates drilled to cover three of the four water bottle holes.

I've just ordered a new one, as my last hammy managed to chew a small hole in the base. I'm hopefully going to be able to use the top half of my old cage, so won't need to re-mesh it.

But, I do need to put something over all of the water bottle holes in the new base, with the expectation of having a gnawer!

Basically, I can do the same again, but the problem is that the screws obviously come through to the other side and are sharp (not for the hamster, but for me cleaning it etc!). I wondered if anyone had any bright ideas. Are there any glues that are both strong enough to withstand washing of the cage, but hamster-safe? Or any other ideas anyone might have would be appreciated.

Thanks!