If you are going to fill the space between the tube and allthread, I'd use an expanding foam.
Lead is toxic and a nightmare to work with. The expanding foam has the advantage, from a physics standpoint, of coupling the rod to the tube which increases rigidity. This may actually provide better damping than simply adding mass.
In my stand, I use Teflon washers. A hard, slick material. I also make sure the allthread does not touch the wooden shelves, which are also of a unique composition / construction.
Lead is toxic and a nightmare to work with. The expanding foam has the advantage, from a physics standpoint, of coupling the rod to the tube which increases rigidity. This may actually provide better damping than simply adding mass.
In my stand, I use Teflon washers. A hard, slick material. I also make sure the allthread does not touch the wooden shelves, which are also of a unique composition / construction.