If I put a weight directly on the screen, the glue comes into contact with both the screen and the weight, gluing both together.

Use some sort of non stick barrier between the weight and the screen. Wax paper or those cereal box liner bags, for instance.

Why use glue? If the screen is cut to fit the bottom of the pot (round), it shouldn't go anywhere. The weight of the dirt should keep the screen in place.

@ci_lantro you think wax paper will just peel off cleanly later?

@AnnKH The precut screens I buy are about 1/3rd of the diameter of the bottom. The weight of a heavy soil does keep the screen in place. But when I use a lighter soil, such as volcanic pumice, the screen will move around.

@AnnKH not a bad solution. I may try that. It would be a hassle to always cut cardboard for each gluing, but that probably works.

The wax paper should peel off cleanly but I'd prefer the cereal bag material; it's a lot tougher.

What kind of glue are you using?

For the drainage holes, I use either fiberglass screen material or scraps of landscape fabric. I cut the landscape material in a circle that fits the bottom of the pot; squares of the screen centered over the hole. And I don't glue. Don't have any problems with the materials moving around using a peat based potting soil like Miracle Grow & clones.

You only need a couple drops of glue. The entire surface doesn't need to be glued down, right? Alternatively, rocks.