Practical Methods For Improving Efficiency And Safety Of Painting Operations

Introductions

Introductions
Typical layouts of paint facilities
Nomenclature: paints, coatings, primers, topcoats, enamels, lacquers, basecoats, clearcoats, liquid paints, powder coatings

Surface Preparation – Chemical Methods

Solvent wiping – how to reduce VOC emissions
Chemical methods for removing oil and grease
Iron phosphating
Zinc phosphating
Conversion coatings for aluminum
New novel pretreatments for aluminum

Break

Surface Preparation – Mechanical Methods

Sanding
Abrasive blasting and various abrasives
Measuring/specifying surface cleanliness
Measuring/specifying blast profile

Quiz – Surface Preparation

Lunch

Spray Booth Design

Designing spray booths with common sense
When to use crossdraft, cross-downdraft and downdraft booths
Best types for parts, vehicles, and aircraft
Regulatory requirements – OSHA and NFPA-33
When to operate under positive pressure
When to operate under negative pressure
How to measure the spray booth pressure balance

Break

Spray Booth Exhaust Filters

Spray booth dry filters
Removal of VOC and paint overspray
Single-, two- and three-stage filters
Why single-stage filters should never be used
What does EPA require?
What are filter efficiency and holding capacity?
Measuring pressure differentials
Manometers v Magnehelic® gauges
When to change filters
Preventing spray booth fires in dry filter booths
How to dispose of spent dry filters
Carbon filters for abatement
Use of carbon adsorption and its effect on filter chamber design

Quiz – Spray Booths and Filters

Spray Guns

Principles of atomization
Compressed ai3
Conventional and HVLP air atomizing spray guns
Siphon and gravity-fed spray guns
Electrostatic spray guns - the principles
Airless and air- assisted airless spray guns
Electrostatic bells and discs

Break

Setting up a Spray Gun

Functions of: fluid needle, fluid control knob, air regulator on spray gun, fan control knob
Step-by-step approach
Testing for atomization
Measuring fluid flow rate
Preventing runs and sags

Transfer Efficiency (TE)

Principles of Transfer TE
Why TE is so effective in lowering costs

Lunch

Transfer Efficiency (TE) (Cont)

Painting techniques that improve TE
Equipment considerations that improve TE

Break

Relative Humidity and Dew Point Affect Paint Application

Definitions of moisture content (g/m3), relative humidity (RH%), dew point (oF)
Effect of air temperature on the dew point
Effect of air temperature on RH%
Effect of RH% on drying of paints
Why you must always apply paint above the dew point
Instruments available to measure RH%, temperature and dew point
What is a psychometric chart?
How to read and interpret a psychometric chart

Spray Booth Air Intake Filters

Differences between air exhaust and intake filters
Different intake air filter designs
Common mistakes made when installing air intake filters
Intake air filter chamber design to minimize air turbulence

Spray Booth Energy Management

Calculate your current basic energy costs
Do you know where the energy is going?
Analyze process energy needs
Techniques to reduce energy in your paint booth
Why variable frequency drives (VFDs) make sense?
VFDs v dampers – pro’s and con’s
Use of energy recovery devices
Consider recirculating the air
Use of multi-mode operation to conserve energy
Use of conformal booth design

Water Wash Spray Booths

How they function
Water-wash v dry filter spray booths, pro’s and con’s
Chemicals to remove overspray, prevent corrosion, minimize foaming, kill bacteria
How to control spray booth for optimum filtration of overspray
Prevent “painting of cars in parking lot”

Liquid Coatings by Curing Mechanism

Solvent evaporation
Auto-oxidation
Baked coatings
Polymers
Two-component coatings
Waterborne coatings
UV curable coatings

Importance of Mixing

Mixing – proper methods
Metering of plural component equipment
Pot life as a function of time
Pot life as a function of temperat

Break

Chemical Agent Resistant Coatings (CARC)

What is CARC?
What are CARC primers?
What are CARC topcoats?
What Mil-specs comprise CARC primers and topcoats?
Pro’s and con’s of MIL-C-53039 moisture curing CARC
MIL-DTL-64159 – WD CARC: Pro’s and con’s, Mixing, Application, Effect of dry film thickness, Effect of temperature and humidity, Drying and curing in warm, humid weather

Quiz – Liquid Coatings

Lunch

Powder Coatings Videos

Powder Coating Technology

What they comprise
Why they emit almost zero VOCs
The solution to hazardous waste
Points of opinion regarding disposal of spent powders
How they are applied
Electrostatic and fluidized bed
Available resins: polyester, epoxy, polyurethane, TGIC and more

Paint Defects

Orange peel, blistering, pin holing, cratering, runs & sags, Benard cells, cracking, chalking, water spotting, blushing, wrinkling, and more.
Touch-up procedures to repair defects

Aircraft Spray Booth Design

How aircraft booths differ from vehicle and parts booths
Calculating air velocity in the spraying zone
Maximizing velocity while minimizing energy usage
Allowances for wing tips, tails and overhead requirements

Spray Booth Lighting

OSHA lighting requirements for spray booths
What is the optimum lighting level for a paint booth?
What instruments measure lighting?
How does one measure brightness in a spray booth?
Electrical codes for placing lamps inside or outside a spray booth
How to light the bottom side of an aircraft
State-of-the-art lighting fixtures
Pro’s and con’s of T5, T8 and T12 fluorescent tubes
How brightness of fluorescent tubes decreases with age
How to keep overspray from ruining your booth brightness
Where to position lamps for maximum effect

Break

Pressure Pots

Single-regulated pressure pots
Double-regulated pressure pots
Pressure cups
Siphon cups

Why Spray Guns are often Starved of Air

Plumbing of compressed air lines
Purchasing the correct air hose
Quick disconnects
Other fittings
Preserving air pressure at the spray gun

Quality Control and Commonly used Instruments

Dry film thickness (different instruments)
Wet film thickness
Adhesion – tape pull-off
Adhesion – dolly pull-off
Hardness
Flexibility
Impact resistance
Gloss
Distinctness of Image (DOI)
Drying
Full cure
Color control

Quiz – Lighting, Pressure Pots, QC Testing

Lunch

Environmental

What are Volatile Organic Compounds (VOCs)?
How solvent-based paints are regulated by the EPA and state agencies
Waterborne paints
How waterborne paints are regulated
Hazardous Air Pollutants (HAPs)
NESHAP and MACT standards

Break

Environmental Nomenclature

RACT, BACT, LAER, MACT, NESHAP
Title III
Title V – Operating Permits

Quiz – Environmental

How to use MSDS and Technical Data Sheets for Calculations

Percent by weight vs percent by volume
Vapor pressure
CAS numbers
Chemical names of compounds
Examples of poorly written material safety data sheets (MSDS)
Analytical methods to determine VOC, HAP, water and exempt solvents

Break

Calculations

Calculating VOC/HAP of a single component coating
Calculating VOC/HAP of a plural component coating
Calculating VOC/HAP when thinners are added
Calculating VOC/HAP of waterborne coatings
Calculating emissions from spray booths

What to Expect from a Paint Facility Inspection

Record keeping
Permits
Covered containers
Empty cans
Spray booth filters
Spray guns

End of Class