Testing Welds - Did it Penetrate? The macro etch test is a very valuable test to verify or check for penetration. It is especially valuable when developing a procedure or welding technique. Since it only tests one cross section, it is not always conclusive unless multiple cuts are done for a good sampling. Carbon Steel and Aluminum are relatively easy to etch but other more corrosion resistant alloys like stainless, nickel, titanium, and cobalt alloys require specific etchants and sometimes requ

Impressive penetration magic tricks | Huu Trung