I need to spray the rear of a sheet of heat resistant toughened glass that is needed to form a black mirror in the back of a modern gas fire I used a stove paint some months ago and it’s pealed My glass shop says it’s just a spray coating but I need one that will stay on glass it’s behind the burner The paint that peeled away was The gallery ultra high temp Matt black spray which is stable to 650 c It’s really for metalwork on stoves and fires Can you help ? Rex