Chapter 10 Surface Preparation Flashcards
During surface preparation, surface cleanliness should be inspected ( at a minimmum) the following three times:
Before any surface preparation activities
After surface preparation, and before coating begins
Between each application of coating in a multi-coat system
Factors during surface preparation that may affect service life include:
Visible and Non-visible contamination
Rust on the surface
Mill Scale
Surface Condensation
Old coatings
Existing Coatings
Common design defects include:
Hard to reach or inaccessible areas
Rivets, bolts, or other connectors
Welds
Gaps ( skip welds or surfaces close together )
Overlapping surfaces
Angle iron badly oriented or in complex arrangements
Threaded areas
Dissimilar metals
Sharp edges, particularly on corners or rough-cut plate
Common fabrication defects include:
Weld spatter, skip welds, sharp corners & edges
Four typical SSPC-SP1 pre-cleaning methods include:
Solvent wipe with cloth or rag
Immersion of the substrate in solvent
Solvent spray
Vapor degreasing
Steam cleaning
Emulsion cleaning
Chemical paint stripping
Use of alkaline cleaners
One standard to use with power tool cleaning is:
SSPC-SP3
Two examples of tools used for rotary power tool cleaning are:
Rotary wire brushes
Disc sanders
Two abrasive blasting methods include
Centrifugal blasting Sand-injected water blast Slurry blast Wet abrasive blast Dry grit blasting
Visual guides for abrasive blasting include:
SSPC-Vis 1
ISO 8501-1
SSPC-SP10/NACE 2 limits staining ______ per each unit area
5%
SSPC-SP5/NACE 1 limits staining to ______ per each unit area
0%
SSPC-SP6/NACE 3 limits staining to _______ per each unit area
33%
The two types of abrasive blasting nozzles include:
Straignt
Venturi
When must the specified level of surface cleanliness be achieved and maintained?
Immediately prior to coatings application
Advantages of centrifugal blast equipment include:
- Dust are contained.
- Abrasives are easily recycled.
- Blasting and priming can be an incline operation.
- General overall economy compared to air blasting.
- No compressors, piping, or air handling equipment needed for wheel blasting.
The inspector’s checklist for surface preparation should include:
Ambient conditions Conditions of substrate Pre-blast surface cleanliness Shot/grit size selection Abrasive blasting equipment Surface profile Surface cleanliness after abrasive blasting Operator qualifications Safety
Abrasive media types include:
- Steal grit & shot
- Crushed slag
- Ceramic grit
- Silica sand
- Garnet
- Agricultural abrasives
Abrasive media typically used for recycling include:
Steel shot
Steel grit
List the pressure ranges that categorize:
Low Pressure Water Cleaning:
<34 MPa (5,000psi)
List the pressure ranges that categorize:
High Pressure Water Cleaning:
34 to 70 MPa (5,000 to 10,000psi)
List the pressure ranges that categorize:
High Pressure Waterjetting:
70 to 210 MPa (10,000 to 30,000 psi)
List the pressure ranges that categorize:
Ultrahigh-Pressure Waterjetting:
> 210 MPa (30,000psi)
Three types of water blasting include:
Grit blasting with a shroud
Sand injected water blast
Slurry blast with grit/water mix
The visual guide for use with the NACE-SSPC waterjetting standard is:
SSPC-VIS4 and NACE-VIS 7
Three test methods for surface profile include:
Comparator and coupons
Replica tape
Dial gauge depth micrometer (profilometer)