Chapter 10 - Surface Preparation Flashcards
Factors during surface preparation that may affect service life include?
Residues of oil, grease and soil. Residue of non-visible chemical salt rust on the surface loose or broken mill scale rust scale Anchor pattern defects mechanical cleaning equipment surface condensation old coating that may have poor adhesion or maybe to deteriorated for recoating existing coating that maybe incompatible
Common design defects include
Hard to reach or inaccessible areas
rivets bolts or other connecters
Welds
Gaps particularly skip Welds or surfaces close together
Overlapping surfaces roof plates in water tanks
angle iron badly orientated or in complex arrangements
threaded area
Dissimilar metals
Shape edges, particularly on corners or rough cut plate
Construction aids
Common fabrication defects include
Weld spatter
Skip welds,
Rough welds,
Sharp corners and edges
Four typical SSPC SP 1 pre cleaning methods include?
Solvent wipe with cloth or rag Immersion of the substrate in solvent Solvent spray Vapour degreasing Steam cleaning Chemical paint stripping Use of alkaline cleaners
One standard for use with power to cleaning is
ISO St2
ISO St3
SSPC SP -3
SSPC SP-11
During surface preparation service cleanliness should be inspected as a minimum for the following three times.
Before any surface preparation activities after surface preparation before coating begin
between each application of coating in a multi coat system
Four example of tool used for power tool cleaning are?
Rotary wire brushes Impact tools Needle scaler Rotary scalers Piston scalers Grinders and sanders Disc sanders
Two abrasive blasting methods include?
Centrifugal blasting Send injected waterblast slurry blast wet abrasive blast dry grit blast cleaning air blasting
Visual standards for abrasive blasting include
SSPC - Vis 1
ISO 8501-1
SSPC SP 10 NACE 2 limits staining to ______each unit area
5%
SSPC SP 5 NACE 1 limits staining to _____ per each unit area.
0%
SSPC SP 6 NACE 3 limits staining to _____ per each unit area.
33%
The two types of abrasive blasting nozzles include?
Straight
Venturi
The specified level of surface cleanliness must be achieved and maintained?
Immediately prior to coating application
Advantages of centrifugal blast equipment include
Dust and fines are contained
Abrasives are easily recycled
Blasting and priming can be an inline operation general overall economy compared to air blasting no compressors piping or air handling equipment needed for wheel blasting
Then inspectors checklist for surface preparation should include
Ambient conditions conditions of substrate pre-blast surface cleanliness shot /grit size selection shot /grit cleanliness abrasive blasting equipment service profile surface cleanliness after abrasive blasting operator qualification safety
Abrasive media types include
Shot and grit metallic crushed slag ceramic grit silica sand Garnet agriculture abrasive specialty abrasive
Abrasive media typically used for recycling include
Steel shot
steel grit
List the pressure ranges that categorize low pressure water cleaning high-pressure water cleaning high-pressure water jetting ultra high pressure water jetting
Low pressure water cleaning - <34MPa(5,000 psi)
High-pressure water cleaning - 34 to 70 MPa ( 5,000 - 10,000) psi)
High pressure water jetting - 70 to 210 MPa ( 10,000 - 30,000psi)
Ultra high pressure water jetting > 210 MPa (30,000 psi)
Three types of water blasting include?
Grit blasting with a shroud
Sand injected water blast
The NACE SSPC waterjetting standard is
NACE 5 / SSPC -SP12.
SSPC/VIS 4 and VIS 7 are visual comparators to be used with the standard.
Three test methods for surface profile include?
Comparator and coupons
Replica tape
Digital surface profile gauge
What is the standard for indicating water or oil in compressed air and what is it commonly referred to as?
ASTM D 4285
Blotter test
