Show tell temperatures telltale tell tale paints made with chemicals derived from oil have been made inside to change colors when they reach certain temperatures they can be sprayed or spread on inaccessible spots in aircraft engines or industrial heat exchangers where it is important to know the r maximum n m u m temperatures but difficult f i auf lif to use u se measuring instruments chemicals made from petroleum are used not only in special purpose paints for industrial use but ase in p paints ints tor for homes as well |