Block D – Refinishing

Trends

The relationship between global environmental issues and consumer demand has been a catalyst for innovative VOC compliant product development. Spray gun improvements are increasing transfer efficiency. Nitrogen is being used as an alternative to air.

Booth cycle times are decreasing because of improved application processes and products. Nanotechnology is being used to improve products. For example, scratch resistant and self-healing clear coats, and shrink resistant primer surfacers are becoming more common.

Related Components

All components apply.

Tools and Equipment

See Appendix A.

Task 7 Prepares equipment.

Context

Spray guns and spray booths need to be set up properly to ensure quality refinish results.

Required Knowledge

• K 1 types of refinish products such as sealers, base coats and clear coats
• K 2 types of refinish equipment such as HVLP, and reduced pressure (RP)
• K 3 spray gun air pressure and air volume, and their effects
• K 4 spray gun components such as fluid tips, needles and air caps
• K 5 pneumatic components such as regulators, inline filters and separators
• K 6 product viscosity
• K 7 booth types and construction such as down draft, cross draft and semi-down draft
• K 8 booth operation
• K 9 operating temperatures and humidity, and their effect on topcoat quality
• K 10 air drying systems for water-borne paints
• K 11 effect of positive and negative booth pressures

Sub-task - D-7.01 Performs spray gun setup.

Key Competencies

• D-7.01.01 select spray gun, fluid tip, needle and air cap according to product to be applied
• D-7.01.02 interchange fluid tip, needle and air cap using tools supplied by manufacturer
• D-7.01.03 verify paint gun is clean and properly assembled
• D-7.01.04 adjust air pressure, fluid delivery and fan width according to paint manufacturers’ specifications and application requirements
• D-7.01.05 attach spray gun to appropriate sized hose/coupler to achieve proper spray performance
• D-7.01.06 verify spray pattern is even using strained product to be applied
• D-7.01.07 troubleshoot equipment problems

Sub-task - D-7.02 Prepares spray booth.

Key Competencies

• D-7.02.01 clean spray booth to ensure a dust free environment prior to vehicle or part set-up
• D-7.02.02 verify inline filters are drained and well maintained through visual inspection
• D-7.02.03 adjust spray booth pressure according to booth manufacturers’ specifications
• D-7.02.04 adjust spray booth temperature according to product manufacturers’ specifications
• D-7.02.05 utilize booth space to accommodate work to be accomplished
• D-7.02.06 position air movers for maximum coverage and to decrease flash times
• D-7.02.07 wipe and tack off air lines

Task 8 Uses refinishing materials.

Context

Automotive painters must accurately match colour and apply refinish materials correctly in order to achieve desired colour and finish on vehicle.

Required Knowledge

• K 1 scale and ratios
• K 2 viscosity
• K 3 low and high strength colours
• K 4 chroma, hue and value
• K 5 metamerism (role of light in colour perception)
• K 6 face, pitch and flop of a colour
• K 7 role of air pressure, temperature and solvent selection
• K 8 paint components such as pearls, mica and metal flakes
• K 9 paint code variants
• K 10 methods to obtain formulas
• K 11 proper use of spectrophotometer and colour corrective lighting
• K 12 types of sealers such as tintable, non-tintable and plastic
• K 13 types of additives and their applications
• K 14 types of topcoats such as single-stage, two-stage and multi-coat
• K 15 flash-off times
• K 16 the role of sealers in the refinishing process
• K 17 spray gun techniques and setups
• K 18 types of substrates such as plastic, steel and aluminium
• K 19 reducers, hardeners, activators and accelerators, and their application
• K 20 forced drying and forced curing
• K 21 drying times of materials for two-toning and denibbing
• K 22 contaminants
• K 23 blending techniques such as drop coat, fan coat and orientation coat

Sub-task - D-8.01 Mixes paint.

Key Competencies

• D-8.01.01 confirm paint code and select appropriate variant
• D-8.01.02 agitate toners according to paint manufacturers’ specifications
• D-8.01.03 clean scale before mixing
• D-8.01.04 determine required quantity of paint according to factors such as size of job and coverage required
• D-8.01.05 place mixing cup and tare (zero) the scale
• D-8.01.06 select solvents, reducers and activators according to ambient conditions (humidity/temperature) and job size
• D-8.01.07 pour desired product, reducers and additives according to paint manufacturers’ formula
• D-8.01.08 mix ready to spray product thoroughly according to manufacturers’ specifications
• D-8.01.09 strain paint to remove contaminants to prevent poor spray gun performance

Sub-task - 8.02 Performs colour matching.

Key Competencies

• D-8.02.01 spray test card to achieve desired coverage using spray gun that has been set up to spray the vehicle
• D-8.02.02 spray a let-down panel to determine number of coats required for a multi-coat colour
• D-8.02.03 visually compare test card against an adjacent polished panel in natural light or using colour corrective lighting
• D-8.02.04 adjust colour formula visually for hue, value or chroma as needed to achieve desired result
• D-8.02.05 adjust spray gun or spraying technique as needed to achieve desired result
• D-8.02.06 seek technical support for challenging or non-existent colour formulas

Sub-task - D-8.03 Applies refinish materials.

Key Competencies

• D-8.03.01 select and use cleaning materials such as tack cloths and low-static solvents
• D-8.03.02 select and spray sealer according to manufacturers’ specifications and job requirement
• D-8.03.03 spray colour coat to achieve consistent coverage according to manufacturers’ specifications
• D-8.03.04 blend colour coat to achieve seamless repair according to manufacturers’ specifications
• D-8.03.05 spray clear coat to achieve gloss, mil thickness and texture according to manufacturers’ specifications
• D-8.03.06 verify product is properly flashed prior to subsequent application
• D-8.03.07 correct defects such as fish-eyes, dry spray, tiger stripes and mottling
• D-8.03.08 tack between coats according to manufacturers’ specifications