Iridized glass reflects heat. Projects with large areas of iridized glass are more prone to thermal-shock since the iridized surface reflects more radiant heat than the non-iridized surface. For this reason, you should always decrease heating and cooling rates for schedule segments below 1000° F (538° C).
The first item above, that iridized surfaces won’t stick to each other, is at the heart of the irid-on-irid technique. Let’s get started!