I want to increase the size of my ring but I don't want the jeweler to thin the gold; is this possible?

Absolutely! Proper ring up-sizing is performed by adding a piece of gold to the ring of the same width and thickness as the existing band. If the band is thin to begin with, the jeweler may recommend replacing the entire shank (band portion) of the ring in order to assure that the shank will not crack after sizing. The existing gold is not thinned out when increasing ring size; instead gold is added to the current ring to make it larger. The jeweler buffs, polishes, and cleans the ring in such a way that it would be almost impossible to tell that it was sized.