We only tumble for about 30 minutes. Except for Van Gogh glass there isn't any visible difference ( except the lack of blood LOL). The advantage of the tumbler is that I can do something else while it tumbles.
Maria

tumbling does the same action as shaking in a can, just automated, especially if you are doing a large project. As for the shine, no it won't wear off unless you tumble for 5-8 days with coarse grit or sand. That is how long it takes me to turn bottles into beach glass

Ok thanks, that explains it.

Ok, so newbie here is wondering about this 'tumbling' thing...your pieces aren't breaking apart when you do this??? It would seem that they would smash all up in a tumbler. (?)

No smashing in the tumbler, the action isn't so violent that it breaks things. I'm still having belt issues with my tumbler ,I've replaced two more. I'm taking it to work tommorow and one of my coworkers will see about doing some adjustments on it or me. The last times I used it I only filled it one third full and there was still a broken belt. So I think its probably got something to do with the tension on the belt.After things are tumbled then you can run your hands over it and there are o sharp edges. Very nice if there are any curved or angular edges,
Cindy

Oh Cindy!! What a bummer, that dumb belt issue!!!