Post #138112 by Alnshely on 01/29/2005

Aloha,
Mr 627, I am an ex glass blower, I did research and industrial work. What many don't know, is that glass is a liquid, that is a solid at room temp, the oposite of mercury which is a solid, that is a liquid at room temp. Keep up, the glass in the glaze of any ceramic, just like any glass, has a thermal expansion coefeicient. Glass expands with any heat, and contracts as it cools. This expansion Co. differs from the Ex Co of the ceramic of the mug. Over the years the differing Expasion coefeicients, will eventually crack the glaze. Physics at work. Email any questions to my wife
Mahalo,
Al