You can use the expanding nature of Gorilla glue to your advantage. If you have a joint that is sloppy and needs filling you can put some of it in a cup add a drop or two of water and stir it up. Then apply to the joint and watch it fill all those voids and creep into all the crevices.

Naturally you have to visit it every ten or fifteen minutes to wipe off the excess that oozes out.