Paul C. Buff, Inc. Technical Forum

Yes, no modeling light.

I believe we can cause a dome to fracture by putting something on the inside surface of the dome that will cause that area to absorb some or all of the light, turning it to heat, while allowing the adjacent area to transmit the light energy. Uneven heating of glass can create substantial stess.

It can and did fracture without the modeling light on, with only the energy from the flash tube. Soot should be most effective. Coffee stains might be enough.

There has to be an explainable mechanism. That is my best guess. Maybe someone with a spare dome wants to try it while wearing safety glasses. I would expect that placing the contamination at the edge wouldhave a higher chance of fracture.