I'm thinking of building speaker stands based on the idea of a sonotube. Wood on top and bottom w/a bit of sand on the bottom to keep the stands from being top heavy. I can paint the wood (particle board or whatever), but what would be the best way to finish the cardboard? I see that most sonotubes are covered w/a 'sleeve' of some sort. Would that be the best way to go for me? Thanks in advance.