Cathode
More noble region where electrons are consumed. Reduction occurs at the cathode
Anode
Part of the metal that corrodes. Oxidation occurs
... [Show More] at the anode
Return Path
Connects cathode and anode and allows passage of electrons generated at the anode to the cathode
Electrolyte
Medium that conducts ionic (rather than electronic) current
Negative Electrode
Zinc case which corresponds to the anode in a corrosion cell
High Voltage Detection Types
1. Rolling Spring 2. Smooth Neoprene Flaps 3. Bristle Brush
Low Voltage Detectors Battery Range is:
5-120V DC
General Types of Holiday Detectors
1. Low voltage DC 2. High voltage DC 3. High voltage pulsed DC 4. High voltage AC
Adhesion Failures May be Caused by:
1. Contaminated surface 2. Wrong surface prep. 3. Insufficient profile 4. Exceeding topcoat window
Checking can be Described as:
Line cracks in the coating surface
Causes of Cracking
1. Stress from movement 2. Internal stress as coating ages
Common Cause of Blistering
Surface contaminants: oil, moisture, and/or grease
Pinholes are:
Small holes in the coating
Vacoules or voids are typically caused by:
Air trapped in coating during mixing
Cratering may be caused by:
Air trapped in coating
A powdery, friable layer on the surface of a coating common with epoxy coatings is:
Chalking
Runs, sags and wrinkles are caused by:
1. Coating applied too thickly 2. Too much thinner 3. Surface too hot 4. Improper spray technique
Problems caused by amine blush
1. Surface tackiness 2. Incomplete cure 3. Poor adhesion
Non drying films may be caused by:
1. Environmental issues 2. Wrong/contaminated thinner 3. Manufacturer coating issues
MSDS contains following
1. Stability and reactivity 2. Handling and storage 3. PPE 4. Physical and chemical properties
Coating product data sheets contain
1. Generic type 2. Description 3. Features
4. Color 5. Finish 6. Proper use 7. Performance data 8. VOC values 9. Application methods
3 ways coating is applied
1. Brush 2. Roller 3. Spray
High temp concerns
1. Slow solvent evaporation 2. leaves moisture on coating surface
Low temp concerns
1. Slow cure times 2. Increased viscosity
Guide to enclosures
SSPC Technical Update #6
Project inspection documentation provides
1. QC records 2. Management Information 3. Verification of work 4. Details of non-conformance work
Good records allow management to:
1. Detect design defects 2. Evacuate coating performance 3. Develop ongoing maintenance program 4. Determine annual cost data
Inspection records show:
1. Environmental conditions 2. pretreatment details 3. Cleaning details 4. Materials information 5. Coating applications 6. Tests results
Documentation may include
1. Dail reports 2. Inspection logs 3. Routine reports 4. Monthly/quarterly reports
People who may be required to attend
1. Owner 2. Engineer 3. Ops personnel 4. Specifier 5. Purchase agent 6. Coating manufacturer 7. Coating inspector 8. Project safety 9. Coating applicator
Goals of a pre-job conference
1. HSE discussion 2. Adress/clarify emergency procedures 3. Review SOW 4. Review logistical support 5. Discuss/clarify inspector responsibilities 6. Clarify chain of command
Common errors using replica tape
1. Variation in point to point profile 2. Dirt on tape/guage 3. Guage accuracy 4. Rubbing technique
Standards for replica tape
1. RP-0287-95-Accuracy 2. ASTM 4417-93-Reproducibility
2 types of replica tape
Coarse and extra coarse
Iso comparator grades may by recorded as:
1. Finer than fine 2. Fine 3. Medium 4. Coarse 5. Coarser than coarse
Depth of profile can be evaluated by:
1. Iso comparators 2. Replica tape 3. Digital profile guage
Tests for soluble salts include:
1. Potassium Ferricynide 2. Bresle patch 3. Sleeve test 4. Conductivity 5. Soluble salt meters
Effective inspection spec. for soluble salts should include:
1. Limits of salts acceptable 2. Specific salts limited 3. Test method 4. Frequency of testing 5. Where to administer tests
3 types of soluble salt contamination are:
1. Chlorides 2. Sulphates 3. Nitrates
3 surface profile test methods
1. Comparator and coupons 2. Replica tape 3. Profilometer
NACE SSPC Waterjetting Standard
NACE 5/SSPC-SP12
3 types of water blasting
1. Grit blasting w/shroud 2. Sand injected water blast 3. Slurry blast w/grit & water mix
Ulta high pressure water jetting range
30K to 50K PSI
High pressure water jetting range
10K to 30K PSI
High pressure water cleaning range
5K-10K PSI
Low pressure water cleaning range
Below 5K PSI
Recyclable grit types
1. Steel grit 2. Cast iron 3. Plastic beads
4. Sponge particles
Abrasive media types
1. Shot grit 2. Crushed slag 3. Ceramic grit 4. Silica sand
Checklist items for surface prep.
1. Ambient conditions 2. Substrate conditions 3.Pre-blast surface cleanliness 4. Shot/grit size 5. Shot/grit cleanliness 6. Surface profile 7. Operator qualification
Describe low voltage holiday detectors
Sensitive electronic devices powered by batteries ranging from 5-120V DC
4 Typical SSPC-SP1 pre-cleaning methods
1. Solvent spray 2. Steam cleaning 3. Emulsion cleaning 4. Alkaline cleaners
Common fabrication defects
1. Laminations 2. Gouges 3. Rough welds 4. Corners
Common design defects
1. Inaccessible areas 2. Welds 3. Gaps 4. Dissimilar metals 5. Overlapping surfaces
Factors that may affect surface prep.
1. Residues-oils, grease, soil 2. Chemical salts residue 3. Rust on surface 4. Mill scale 5. Anchor pattern issues
Surface prep should be inspected a minimum of what 3 times?
1. Before surface prep. 2. After prep, before coating 3. Between coating applications (multiple coats)
Inspectors responsibilities as they relate to spec.
Observe and report all technical aspects of a coating project
5 Formal specification sections
1. Scope of work 2. Terms and Definitions 3. Reference standards and codes 4. Safety 5. Surface preparation
Oil based coatings applied over alkaline surfaces may result in:
Saponification: High Ph forms a soap like material which reacts between the two coatings
Industrial and marine coatings are commonly referred to by:
Generic resin type
Main ingredients for hydration coating to cure
Same level of humidity as surrounding [Show Less]