Destructive Instruments & Tests

Question 1

The inspector should not perform destructive testing unless what?

Answer 1

• Specification allows it
• Owner requires or allows it
• Tests are required for failure analysis

Question 2

What is ASTM D 4752?

Answer 2

Test Method for Measuring MEK Resistance for Ethyl Silicate Zinc Rich Primers by Solvent Rub

Question 3

What is ASTM D 5402?

Answer 3

Standard Practice for Assessing the Solvent Resistance for Organic Coatings Using Solvent Rubs

Question 4

What is ASTM D 4138?

Answer 4

Measurement of DFT of Protective Coating Systems by Destructive Means [Method A]

Question 5

Describe the solvent sensitivity test.

Answer 5

To perform the solvent sensitivity test:
• Select and clean area for test
• Fold 100% cotton shop cloth into 2 layers
- Approximately 300 mm x 300 mm (12 in. x 12 in.)
- Contrasting in color to the coating to be evaluated
• Saturate cloth with MEK and keep saturated during test
• Rub cloth back and forth on coated surface until substrate is revealed or for 50 double-rubs
• Assess results
• Compare with control area

Question 6

What is the Scale of Resistance Reading for Inorganic Zinc (ASTM D 4752)?

Answer 6

5 = No effect on surface
4 = Burnished appearance, some zinc on cloth
3 = Some marring and apparent depression of film
2 = Heavy marring, obvious depression
1 = Heavy depression, no actual penetration to substrate
0 = Penetration to the substrate in 50 or fewer double-rubs

Question 7

What is a Paint Inspection (Tooke) Gauge?

Answer 7

• Used to measure total coating thickness and the thickness of individual layers of coatings in multi-coat films
• May be used to see microscopic cracking, tendency for brittleness, blistering, or other microscopic anomalies
• May be used to inspect the substrate
• Used frequently in failure analysis

Question 8

Describe the test procedure for a tooke gauge.

Answer 8

• Mark the surface
• Cut the coating at right angles to the pen mark by pulling the gauge towards you
Note: Must penetrate to substrate
• Position the gauge over the cut
• Turn on light
• Align the reticle scale parallel to the cut
Note: One side of cut straight edge, other ragged
• Measure the width of the cut coating (or coatings) by counting the number of graticule divisions

Question 9

An elcometer 121-4 gauge requires calibration.
True or false?

Answer 9

False, it cannot be calibrated

Question 10

What are the operating parameters of an elcometer 121-4 gauge?

Answer 10

Measures coating thickness with a DFT maximum of 2000 um (80 mils)

Question 11

What are common errors made with an elcometer 121-4 gauge?

Answer 11

Common errors:
• Not applying enough pressure
• Pushing gauge away rather than pulling towards
• Reading results on the wrong side of the cut
• Using the wrong cutting blade for coating thickness

Question 12

A saberg drill does not require calibration.
True or false?

Answer 12

True, this instrument does not require calibration

Question 13

What are the operating parameters of a saberg drill?

Answer 13

Operating parameters:
• Measures coatings up to 1500 um (60 mils)

Question 14

What are the common errors made with a saberg drill?

Answer 14

Common errors include:
• Using the incorrect hand wheel
• Using the wrong conversion factor
• Using excessive pressure when rotating the hand wheel

Question 15

What is the difference between an elcometer 121-4 gauge and a saberg drill?

Answer 15

Elcometer 121-4 uses a cut
Saberg drill bores a hole

Question 16

What is ASTM D 6677?

Answer 16

Evaluating Adhesion by Knife Destructive Test Method

Question 17

What is ASTM D 3359?

Answer 17

Standard Test Method for Measuring Adhesion by Tape Test

Question 18

What is ASTM D 3359 Method A

Answer 18

X-Cut Test Method for Measuring Adhesion by Tape Test

Question 19

What is ASTM D 3359 Method B

Answer 19

Cross Hatch Test Method for Measuring Adhesion by Tape Test

Question 20

X-Cut Test Method for Measuring Adhesion by Tape Test is used for coating films thinner than 5 mils.
True or false?

Answer 20

False, this method is used for coating films thicker than 5 mils

Question 22

What are the ASTM descriptions to rate adhesion by the X-cut method (Method A)?

Answer 22

• 5A No peeling or removal
• 4A Trace peeling or removal along incisions or at their intersections
• 3A Jagged removal along incisions up to 1.6 mm (0.0625
in.) on either side
• 2A Jagged removal along most of incisions up to 3.2 mm
(0.125 in.) on either side
• 1A Removal from most of the area of the X under the tape
• OA Removal beyond the area of the X

Question 23

Describe how to make cuts for the Cross Hatch (Method B)

Answer 23

If making the cuts individually:
• Cuts are made at right angles to each other
• Films thinner than 50
um (2 mils), 11 cuts 1 mm apart
• Films from 50 to 127 um (2 to 5 mils) thick, six cuts are made 2 mm apart

Question 24

What are the ASTM descriptions to rate adhesion by the cross hatch method (Method B)?

Answer 24

• 5B The edges of the cuts are completely smooth; none of the squares of the lattice are detached.
• 4B Small flakes of the coating are detached at intersections;
less than 5% of the area is affected.
• 3B Small flakes of the coating are detached along the edges and at the intersections of the cuts. The area affected is 5 to 15% of the lattice.
• 2B The coating has flaked along the edges and on parts of the squares. The area affected is 15 to 35% of the lattice.
• 1B The coating has flaked along the edges of cuts in large ribbons, and whole squares have detached. The area affected is 35 to 65% of the lattice.
• OB Flaking and detachment worse than Grade 1B.

Question 25

What are the types of failures during an adhesion pull test?

Answer 25

• Adhesion
• Cohesion
• Adhesion & Cohesion

Question 26

What are the two methods of determining hardness of a coating?

Answer 26

• Pencil hardness
• Indentation (impressor) hardness

Question 27

What is ASTM D 3363?

Answer 27

Standard Test Method for Film Harness by Pencil Test

Question 28

What angle do you hold the pencil while performing a pencil hardness test?

Answer 28

45 degree angle and push away from the operator in a 0.25” stroke

Question 29

What pencil should you start with for a pencil hardness test?

Answer 29

Start with the hardest pencil (6H) down the scale (6H to 6B)

Question 30

What is ASTM D 2583?

Answer 30

Standard Test Method for Indentation Hardness of Rigid Plastics by Means of a Barcol Impressor

Question 32

Describe the test procedure for Testing with Barcol Impressor

Answer 32

• Place the impressor, the calibration disks, and the test material on a smooth, hard supported surface.
• Set the point sleeve (indenter housing) on the test surface.
• Set the legs on the same surface, or on solid material of the same thickness so the indenter is perpendicular to the test surface.
• Grasp the instrument firmly between the legs and point sleeve.
• Quickly, by hand apply increasing force on the case until the dial indication reaches a maximum (note: drift-in readings from the maximum may occur in some materials).
• Record this maximum reading

Question 33

According to ASTM D 3359, Method B (Crosshatch) can be performed on coating thickness of (Select all that apply.)
A. 6 mils (153 microns)
B. 4 mils (102 microns)
C. 2 mils (51 microns)
D. 10 mils (250 microns)

Answer 33

B. 4 mils (102 microns)
C. 2 mils (51 microns)

Question 34

DFT measurements by destructive means (ASTM 4138) requires the use of which of the following? (Select all that apply.)
A. Tooke gauge
B. The Patti unit
C. Saberg Drill
D. Eddy Current gauge

Answer 34

A. Tooke gauge

C. Saberg Drill

Question 35

ASTM D 4752 is a destructive test to determine the cure of ethyl silicate inorganic zinc by rubbing the surface with
____________ ?
A. Fifty (50) double rubs using an agreed upon solvent
B. A minimum of twenty-five (25) double rubs using an agreed upon solvent
C. Fifty (50) double rubs using an non-photo-chemically reactive solvent
D. Fifty (50) double rubs using methyl ethyl ketone (MEK)

Answer 35

D. Fifty (50) double rubs using methyl ethyl ketone (MEK)

Question 36

When applying an adhesion dolly to a painted concrete surface, you should be sure to _________?
A. Use a smooth dolly
B. Remove excess adhesive
C. Twist the dolly
D. Use the smallest dolly

Answer 36

B. Remove excess adhesive

Question 37

The solvent sensitivity test ASTM D5402 can be used to determine the cure of which coating?
A. Coal tar cut back
B. Vinyl
C. Galvanizing
D. Ероху

Answer 37

D. Ероху

Question 38

Which test determines a coatings resistance to indentation or impression?

A. Rilem tube
B. Durometer
C. Anemometer
D. Tooke gauge

Answer 38

B. Durometer