PCS Coating Application Techniques 2

Question 1

When spraying a large flat steel surface by conventional or airless spray, what overlap between passes is generally recommended to achieve uniform film thickness?

Accepted Answer

About 50%

Answer

A 50% overlap on each pass helps even out the thinner film at the edges of the spray fan and gives uniform DFT.

Question 2

An airless spray tip is marked 517. What does the '17' indicate?

Accepted Answer

Orifice diameter of 0.017 inch

Answer

In common airless tip coding the last two digits give the orifice size in thousandths of an inch, so 17 means 0.017 in.

Question 3

What is the main purpose of applying a stripe coat before the full coat?

Accepted Answer

Add extra film build on edges, welds, and corners where spray film tends to be thin

Answer

Stripe coating by brush or roller adds film to edges, welds, bolts, and crevices, where film pulls back and goes on thin.

Question 4

Holding a spray gun at an arc (pivoting the wrist) instead of moving it parallel to the surface usually causes what?

Accepted Answer

Thin film at the ends of the stroke and heavy film in the middle

Answer

Arcing changes the gun-to-surface distance, so the film goes on heavy where the gun is close and thin at the ends of the stroke.

Question 5

For airless spray, what gun-to-surface distance is commonly recommended?

Accepted Answer

12 to 18 inches

Answer

Airless guns are typically held about 12 to 18 inches from the surface to balance atomization, transfer efficiency, and film build.

PCS - Protective Coatings Specialist Certification Practice Test

PCS - Protective Coatings Specialist Certification Practice Test

PCS Coating Application Techniques 2