Following the guidelines of world-recognized conservation experts, Associated Crafts & Willet Hauser maintains a CONSERVATION PHILOSOPHY to preserve the original artwork wherever structurally reasonable. Therefore we do not, as a matter of course, replace individual pieces of cracked or faded painted glass unless individually specified. Once a piece of glass is deemed broken and in need of replacement our studio has the resources to provide the best possible match available. Bulging occurs in most stained glass windows due to years of exposure, heat build-up, gravity, settling, or improper bracing.