What is the cause of chalking in epoxy coating - UV or radiation exposure
What is polymerization cured coating? - Two parts mixed together just prior
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Examples of non-convertible coatings - 1. Chlorinated rubber 2. Vinyl 3. Acrylic 4. Bituminous
Non-convertible curing def. - No chemical change during cure cycle
Convertible curing def. - Some chemical change during cure cycle
What info should be included when sending samples to a lab? - 1. Identity of materials 2. Properly packed/labeled samples 3. Chain of custody form 4. Type of analysis that is expected and the concentrations of interest
Specialized tests or equipment coating inspectors may encounter - 1. AA/AE Atomic Absorption/Emission 2. ISP Induction coupled plasma Spectrometer 3. GLC Gas liquid chromatographs 4. IR, FTIR, FTIR-ATR INfrared spectrophotometers 5. DSC Differential scanning calorimeters
What is a cathodic dis-bondment test? - Procedure to determine how easily a coating loosens from a substrate or develops holidays as a result of normal soil potentials
Individuals who perform surveys - 1. O-Cat or S-cat tech 2. NACE coating specialist 3. NACE Level III 4. Coating Inspector w/field experience 5. Coating manufacturer representative 6. Maintenence engineer with specific plant knowledge.
Coating survey steps - 1. Understand scope 2. Gather team 3. Develop survey plan 4. Review standards 5. Agree on format 6. Delegate various tasks 7. Eveluate existing coating 8. Delegate various tasks 9. Evaluate existing coating 10. Gather additional info 11. Summarize data 12. Prepare maintenance plans 13. Prepare reports/input data 14. Submit final survey reports.
List some of the primary reasons surveys are performed - 1. Plan maintenance. 2. Prioritize work 3. Budgetary concerns 4. Determine value of assets 5. Legal compliance
Definition of a coating survey - Gather baseline info needed to plan maintenance coating procedures
What are faying surfaces and why not galvanize them? - Surfaces that depend on friction to hold galvanizing it may/will reduce friction if they are galvanized
Common problems seen during the usual inspections of HD galvanized items - 1. Cracking 2. Peeling 3. Bare spots 4. Lumps 5. Blisters 6. Flux inclusions 7. Ash inclusions 8. Dross inclusions
Post galvanizing treatments and why - To Remove Thickness: Roll, Wipe, Centrifuge/Air Blast
To change properties/To alloy: Annealing
Temperature range for galvanizing kettle - 820-850 F
Purpose of pickling - Hydrochloric or sulfuric acid bath to remove oxides and mill scale
Purpose of caustic cleaning - Acid bath or caustic to remove dirt, oil and grease
Stages of hot dip process - 1. Surface prep. 2. Galvanizing 3. Post treatment 4. Inspection
Hot dip galvanizing safety - 1. Can stay for some time 2. Molten metal splash 3. Nascent hydrogen above kettle
Usual layers of galvanized coating consists of: - 1. ETA=100% Zn 2. ZETA= 94% Zn 6%Fe 3. DELTA= 90% Zn 10 Fe 4. GAMMA= 75% Zn 25% Fe
What is hot dip galvanizing? - Coating iron or steel with zinc at temperatures of 820-860 F
If a maintenance coating to be applied is incompatible with the existing coating system__________may occur - Curling
______________ is performed at the work area by working the edges of the repaired area back to achieve a fairly smooth transition from the repair area to sound coating. - Feathering
With regards to maint. coating all parties should agree on___________? - 1. Spot repair requirements 2. Feathering 3. Appearance of repaired areas
Maint. coating selection process should take the following into consideration: - 1. Compatability with existing system 2. Surface prep. 3. If abrasi ve blast is permitted and feasible
When determining coating system life cycle the following should be considered: - 1. Maint. costs 2. Length of coating life 3. Initial and maint. material costs 4. Intial and maint. labor costs
Life cycle of a coating system can be affected by: - 1. Service environment 2. Maint. intervals 3. Coating system chosen 4. Surface condition [Show Less]