Destructive Instruments & Tests Flashcards
The inspector should not perform destructive testing unless what?
- Specification allows it
- Owner requires or allows it
- Tests are required for failure analysis
What is ASTM D 4752?
Test Method for Measuring MEK Resistance for Ethyl Silicate Zinc Rich Primers by Solvent Rub
What is ASTM D 5402?
Standard Practice for Assessing the Solvent Resistance for Organic Coatings Using Solvent Rubs
What is ASTM D 4138?
Measurement of DFT of Protective Coating Systems by Destructive Means [Method A]
Describe the solvent sensitivity test.
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
What is the Scale of Resistance Reading for Inorganic Zinc (ASTM D 4752)?
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
What is a Paint Inspection (Tooke) Gauge?
• 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
Describe the test procedure for a tooke gauge.
• 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
An elcometer 121-4 gauge requires calibration.
True or false?
False, it cannot be calibrated
What are the operating parameters of an elcometer 121-4 gauge?
Measures coating thickness with a DFT maximum of 2000 um (80 mils)
What are common errors made with an elcometer 121-4 gauge?
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
A saberg drill does not require calibration.
True or false?
True, this instrument does not require calibration
What are the operating parameters of a saberg drill?
Operating parameters:
• Measures coatings up to 1500 um (60 mils)
What are the common errors made with a saberg drill?
Common errors include:
• Using the incorrect hand wheel
• Using the wrong conversion factor
• Using excessive pressure when rotating the hand wheel
What is the difference between an elcometer 121-4 gauge and a saberg drill?
Elcometer 121-4 uses a cut
Saberg drill bores a hole
What is ASTM D 6677?
Evaluating Adhesion by Knife Destructive Test Method
What is ASTM D 3359?
Standard Test Method for Measuring Adhesion by Tape Test
What is ASTM D 3359 Method A
X-Cut Test Method for Measuring Adhesion by Tape Test
What is ASTM D 3359 Method B
Cross Hatch Test Method for Measuring Adhesion by Tape Test
X-Cut Test Method for Measuring Adhesion by Tape Test is used for coating films thinner than 5 mils.
True or false?
False, this method is used for coating films thicker than 5 mils
What are the ASTM descriptions to rate adhesion by the X-cut method (Method A)?
• 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
Describe how to make cuts for the Cross Hatch (Method B)
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
What are the ASTM descriptions to rate adhesion by the cross hatch method (Method B)?
• 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.
What are the types of failures during an adhesion pull test?
- Adhesion
- Cohesion
- Adhesion & Cohesion
What are the two methods of determining hardness of a coating?
- Pencil hardness
- Indentation (impressor) hardness
What is ASTM D 3363?
Standard Test Method for Film Harness by Pencil Test
What angle do you hold the pencil while performing a pencil hardness test?
45 degree angle and push away from the operator in a 0.25” stroke
What pencil should you start with for a pencil hardness test?
Start with the hardest pencil (6H) down the scale (6H to 6B)
What is ASTM D 2583?
Standard Test Method for Indentation Hardness of Rigid Plastics by Means of a Barcol Impressor
Describe the test procedure for Testing with Barcol Impressor
- 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
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)
B. 4 mils (102 microns)
C. 2 mils (51 microns)
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
A. Tooke gauge
C. Saberg Drill
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)
D. Fifty (50) double rubs using methyl ethyl ketone (MEK)
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
B. Remove excess adhesive
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
D. Ероху
Which test determines a coatings resistance to indentation or impression?
A. Rilem tube
B. Durometer
C. Anemometer
D. Tooke gauge
B. Durometer
