Originally Posted by
morgothaod
I think I probably wasn't rubbing hard enough when sanding (The tire should look different after sanding the area, right?)
DON'T rub too hard or you'll rub right through the tube! You just want to take the "shine" off, which when that happens it's actually roughing up the tube slightly, you should not see small groves cutting into the surface of the tube, that means you're rubbing too hard. Again just lightly sand it just enough to take the shine off the surface of the tube.