Originally Posted by Tourist in MSN

I had a seatpost (painted black) that was slightly undersize, kept sliding down. Got tired of that, so I cleaned off the grease and masked off the part of the post above where the post went into the frame. Then sprayed a few thick layers of black spray paint onto the post. Let the paint dry and harden sitting outside for about a week where it was in the sun during the day. Then put it in the bike. The extra thickness of about three layers of spray paint was enough to make it slightly bigger and quite slipping.