If the Part Is Too Large to Submerge in a Chemical Bath, How Can you Tell If All Areas of the Part Have Been Treated?

If immersion of the stainless steel piece is impractical due to size, the acid solution may be applied with a suitable swab and removed by rinsing with water. There are several tests which can be performed on the oversized part to determine passivity such as a high humidity test, salt spray test, copper sulfate test or free iron test.