ASNT Level III- Visual & Optical Testing

Wear can be determined in a similar manner by replicating and comparing a
worn surface to an unworn surface (see Fig. 63). Fracture surfaces with rough
contours can be easily replicated with silicone (taking an acetate replica of
such surfaces is difficult). However, the resolution characteristics of a silicone
replica are not as good as acetate replicas and this limits the amount of
interpretation that can be performed. Macroscopic details such as chevron
markings can be easily located with the silicone technique to determine crack
propagation direction or to trace a fracture path visually to its origin.
Charlie Chong/ Fion Zhang