A lot of my sculptural woodwork starts off by gluing up thicker blocks of wood from walnut, cherry, and/or maple. I use a 6" jointer to flatten the faces and sometimes follow up with sanding on a plate of glass with 100 grit before gluing just to make sure the joint surfaces are perfectly flat. If I glue boards up face to face (original Titebond) they still somehow manage to get small gaps in the joint and also have a tendency to slip around as I tighten the clamps. The blocks are not very large, maybe 4 or 5 board feet at the most. How do most woodworkers handle this?