Introduction Flashcards
(79 cards)
1
Q
The Initial Surface Cleaning and Prep is the key step to the ___ of the coating system.
A
Success
2
Q
Modern coatings require both a ___ and ___ surface if they are going to have long-term stability.
A
Clean and Roughened
3
Q
Surfaces where protective coatings are applied may include?
A
Steel
Galvanized Surfaces
Aluminum
4
Q
What is the most common surface prepared and coated for protection?
A
Steel
5
Q
Residues of Oil, Grease, and soil on a substrate can?
A
Prevent Adhesion
6
Q
Residues of (non-visible) Chemical Salts on a substrate can?
A
Induce Corrosion after coating.
7
Q
Rust on a substrate can interfere with?
A
Adhesion
8
Q
Loose or broken mill scale on a substrate can cause?
A
Early coating failure.
9
Q
Tight/adherent mill scale can cause?
A
Later coating failure.
10
Q
Rust Scale cannot be protected by any coating and cannot maintain?
A
Adhesion to steel.
11
Q
Anchor Patterns may be so rough that?
A
Peaks are formed.
12
Q
Peaks in an anchor pattern are difficult to adequately?
A
Protect with coating.
13
Q
If the anchor pattern is not rough enough it could cause failure because of a?
A
Loss of adhesion.
14
Q
Sharp ridges, burrs, edges, or cuts can prevent adequate?
A
DFT
15
Q
Surface condensation, if coated over, may cause?
A
Blistering and delamination.
16
Q
Old coatings have ___ ___ or may be too deteriorated to recoat.
A
Poor Adhesion
17
Q
Existing coating can be incompatible with and ___ by application of maintenance coating.
A
Affected
18
Q
Surfaces to be coated require?
A
Precleaning
19
Q
Inspection for contamination is an important component of the?
A
Coating process.
20
Q
Inspection for surface cleanliness should take place?
A
Before Surface Prep.
After Surface Prep before coating.
Between each coat.
21
Q
The first essential step of surface prep is to consider the ___ ___ to be coated.
A
Specific surface.
22
Q
Substrates can include,
A
New/unpainted steel. Steel with Mill Scale. Corroded Steel Corroded Zinc or Zinc Galvanized. Corroded Aluminum.
23
Q
New steel is relatively easy to clean if it is ___.
A
Unpainted.
24
Q
New steel is relatively easy to clean if it is unpainted. Provided the steel is not exposed to corrosion in a ___ or ___ environment.
A
Chemical or Marine
25
The biggest issue with surface prep of new steel structures is likely to be?
Removal of mill scale.
26
Blast cleaning either with shot or grit (or a mix of the two) can easily remove most?
Mill Scale.
27
An advantage of using grit for blasting is the?
Simultaneous creation of an angular surface profile.
28
Tightly adherent mill scale can be difficult to remove without?
Blast Cleaning.
29
Mill scale is formed on new steel by a reaction between the ___ ___ and ___ in the environment during production.
Hot steel and oxygen.
30
The surface of newly produced, hot rolled steel is generally covered with blue black deposits of?
Mill scale.
31
Adhesion of mill scale to steel is unpredictable and varies from?
Tightly adherent to lightly adherent.
32
Overcoating mill scale can cause the mill scale to?
Delaminate.
33
Mill scale is relatively ___. A factor that is significant for today's high build, fast-drying coatings.
Smooth.
34
Adhesion of coatings to smooth mill scale may be poor, resulting in failure due to?
Loss of adhesion.
35
Mill scale is ___ relative to bare steel.
Cathodic
36
When steel is partially covered in mill scale and exposed to corrosion the cathodic mill scale doesn't corrode because it is?
Protected by the anodic steel.
37
When most of the surface is covered by mill scale, corrosion at the anodic areas may be accelerated by the?
Unfavorable Area Effect
38
The unfavorable area effect is?
A large Cathode + A small Anode = Rapid corrosion at the anode.
39
For best results, clean mill scale from new steel by?
Abrasive blast cleaning.
40
When previously coated steel needs to be recoated, remove old coating by sanding, abrasive blasting or stripping any coating that:
Has poor adhesion.
Is to deteriorated to recoat.
Is incompatible with or affected by maintenance coatings.
Is peeling or degraded in any way.
41
If a previous coating is completely intact:
1. Clean the surface with?
2. Scuff sand to?
1. A strong detergent or solvent.
| 2. Remove Gloss.
42
After cleaning and scuffing the surface of previously painted steel with an intact coating, perform these two tests?
Spot Test and Adhesion Test.
43
To perform a spot test:
Apply a small amount of the new coating over the old paint. If the old finish wrinkles or lifts within 30 minutes this indicates a need to?
Remove the old coating.
44
Since a spot test can be destructive what should the inspector do prior to performing the test?
Seek permission.
45
To perform an Adhesion test, if the coating does not wrinkle or lift after the spot test:
Cut an X into the coating. Place tape firmly over the cut, then pull with a hard/fast pull. If the coating fails?
Remove it or consider an appropriate barrier coating.
46
ASTM D3359 is the standard for the?
Tape Adhesion Tet.
47
Coat freshly galvanized steel ___ ___ ___ or allow it to oxidize sufficiently, then prepare the substrate prior to coating as per the specification.
Within 24 hours.
48
Coat freshly galvanized steel within 24 hours or allow it to ___ ___, then prepare the substrate prior to coating as per the specification.
Oxidize sufficiently.
49
Atmospheric exposure develops a passive film of ___ or ___ ___ on the surface of galvanized steel/Zinc.
Oxide and/or Zinc Carbonate
50
If the layers of Oxide and/or Zinc Carbonate on Galvanized/Zinc surfaces are tightly adherent they help coatings adhere because of their?
Relative roughness.
51
Remove any loosely adherent or powdery Oxide/Zinc Carbonate surfaces prior to?
Coating.
52
What is an effective method of removing oxide/zinc carbonate from substrates?
Pressure washing with lots of clean fresh water.
53
Pressure washing oxide/zinc carbonate is less effective than?
Blast Cleaning.
54
When blast cleaning Oxide/Zinc Carbonate, lightly ___ ___/___ ___ the surfaces to roughen them prior to coating. Or treat with an acid-based solution. (e.g. Acid-etch primer or acid-wash solution.) to provide a clean surface with a profile.
Blast clean/Brush blast
55
When blast cleaning Oxide/Zinc Carbonate, lightly blast clean (Brush blast) the surfaces to roughen them prior to coating. Or treat with an ___ ___ solution. (e.g. Acid-etch primer or acid-wash solution.) to provide a clean surface with a profile.
Acid Based Solution.
56
Galvanized/Zinc:
| Current thinking suggests that 1___ ___ before coating provides a better result than 2___ ___ to provide goo adhesion.
1. Blast cleaning.
| 2. Etch Primers
57
Oil based coating such as aklyds or epoxy esters perform poorly on galvanized or zinc coating structures because of a reaction called?
Sopanification.
58
This reaction, a formation of soap, causes degradation of an oil-based binder and consequent loss of adhesion to zinc surfaces.
Sopanification.
59
New aluminum surfaces may develop a protective ___ film that exhibits low adhesion to the substrate.
Oxide
60
If oxide on aluminum is coating with an organic coating, the oxide film could?
Detach from the surface.
61
With anodized aluminum the oxide film ___ ___ to the substrate and can be ____ with ___ ___. However, this requires a light abrasion of the surface before application.
Adheres tightly to the substrate and can be coated with an organic coating.
62
When applying an organic coating, over anodized aluminum that presents tightly adherent Oxide, it requires? S
A lightly abraded surface.
63
When applying an organic coating, over anodized aluminum that presents tightly adherent Oxide, it requires a lightly abraded surface. Sometimes only ___ and ___ ___ are sufficient surface prep.
Degreasing and water rinsing.
64
When applying an organic coating, over anodized aluminum that presents tightly adherent Oxide, it requires a lightly abraded surface. Sometimes only degreasng and water rinsing are sufficient surface prep. However, it may also be necessary to prepare the surface by ___ or ___ ___ ___ with a fine particle sand or plastic abrasive.
Wet or Dry abrasive blasting.
65
When applying an organic coating, over anodized aluminum that presents tightly adherent Oxide, it requires a lightly abraded surface. Sometimes only degreasng and water rinsing are sufficient surface prep. However, it may also be necessary to prepare the surface by wet or dry abrasive blasting with a ___ ___ ___ or ___ abrasive.
fine particle sand or plastic.
66
Avoid a high profile on?
Aluminum
67
Check corroded aluminum surfaces for?
Oxidation.
68
Aluminum, like zinc and zinc coated surfaces, form a passive film of ___ ___ in atmospheric exposure.
Aluminum Oxide
69
___ ___ or ___ ___ aluminum surfaces to remove powdery or loosely adherent aluminum salts before coating.
Lightly blast or wire brush.
70
A special aluminum surface treatment (i.e. ___ ___) may be required before coating.
Etch Primer
71
For aluminum select a primer with known ___ and ___ ___ to a clean surface.
Compatability and Strong Adhesion
72
ASTM D 1730
The preparation of Aluminum and Aluminum Allow Surfaces for Painting.
73
Uncoated stainless steel reacts with the atmosphere to produce a protective film which is an essential part of its?
Corrosion protection.
74
Prior to coating stainless steel you must remove all of its ___ ___ ___ or it may detach from the substrate.
Natural protective film.
75
The protective films formed on stainless steel are generally ___ and ___ ___.
Tough and tightly adherent.
76
Some types of stainless steel tend to become ___ ___ when exposed to an unsuitable environment.
Rust Spotted.
77
If Rust Spotting occurs on stainless steel it may be necessary to either ___ or ___ remove it.
Totally or partially.
78
If Rust Spotting occurs on stainless steel it may be necessary to either totally or partially remove it via ___ or ___ ___ ___ cleaning.
Wet or dry abrasive blast cleaning.
79
When blasting rust spotting from stainless steel use a 1___ ___ abrasive or scrub with 2___ and a ___ ___ brush.
1. Nonmetallic Abrasive.
| 2. Water and a stiff bristle brush.
