Help
I'm trying to save this tablebtop. It was damaged and now some parts are wavery. I sanded it to remove the varnish but I don't know how to stick the thin layer back.
I'm sure someone with better skills and knowledge will answer, but to me I'm afraid that looks like the veneer has gotten wet and come away from the substrate (and split into the bargain) You could try glue and pressure to get it back down, but otherwise I think you'd have to put on a whole new veneer. I don't believe it really 'fixes' very well.
I've not got experience with repairs like this but I would cut the lifted veneer with a very sharp knife, scrape any adhesive off the back and out of the hole and reglue with lots of pressure from something flat with as much weight as you can get on it. It won't be perfect but it will be flat again.
Flood that section with thin cyanoacrylate glue, then use a caul( flat board with plastic on the face to keep it from gluing itslf to the table) to press it down. If you dont have clamps that deep, use 2x2s to span over the caul and clamp both ends of each stick. Let it dry overnight. Don't use accelerator on the glue. In the future, glue the veneer down before sanding.