Paint Mixing and Reducing

26

Paint Mixing and Reducing

Chapter

Permission granted to reproduce for educational use only.© Goodheart-Willcox Co., Inc.

Objectives

After studying this chapter, you will be able to:• Know where to find a paint code on a vehicle.• Understand how to use the paint code to obtain the

paint part number.• Understand the importance of thoroughly stirring

tints.• Explain how to mix a color.• Know how to reduce paint by volume, percentage,

and weight.


Paint Mixing

• Paint code– Letters, numbers, or combination– Represents color of vehicle– Paint code location varies by vehicle manufacturer


Paint Mixing (Cont.)



• Paint code– Date of vehicle manufacture– Code may be same for different years



• Paint part number– Number assigned by specific paint manufacturer– Unique to each paint manufacturer– Different paint part number for each paint code



• Paint part number– Find paint part

number with paint code

• Color chip book• Paint code/paint

part number CD• Paint

manufacturer’s web site



• Alternate paint part numbers– Same paint code– Slightly different color on vehicle– Reasons for different colors

• Vehicles built at different factories• Different paint manufacturers• Spraying conditions, equipment at factories are

different



• Alternate paint part numbers– Alternate deck

of color chips– Check chip

against vehicle– Select best

matching alternate



• Alternate paint part numbers– Underhood color

• Similar to exterior color• Lacks metallic or pearl



• Paint sources– Jobber

• Sells paint• Mixed by jobber• Sells factory-pack color paint• Supplied by paint manufacturer

– Intermix• Mixed at shop • Uses tints supplied by jobber



• Paint mixing equipment– Digital scale

• Weighs tints• Accurate to 100th of a

gram• Digital readout• Zero scale by pressing

bar



• Paint mixing equipment– Tint mixing bank

• Stirs and stores tints

– Paint shaker• Stirs tints



• Paint mixing supplies– Tints

• High-strength• Low-strength• Powder pearl• Metallic tint



• Paint mixing supplies– Binder

• Forms paint film when dry

– Balancer• Corrects ratio of pigment to binder• Flake control



• Paint mixing supplies– Comprehensive tint system

• Add tints to create paint

– Single tint system• Add tints, binder, and balancer to create paint



• Paint formula– Recipe for specific color– List of tints– List of weights of each tint



• Paint formula– Quantitative formula

• Lists required weight of each tint

– Cumulative formula• Lists weight of entire mixture as each tint is added



• Color creation– Stir tints for 15 minutes twice per day– Stir new tints for 30 minutes– Stir tints five minutes before mixing color– Do not mix waterborne paint in metal cans– Remove dried tint from pour spout



• Color creation– Recheck tint number before adding to can– Concentrate while pouring– Add tints to center of can– Start with clean paint can– Follow formula– Add specified amount of each tint



• Overpour– Add too much of one tint– Remove excess tint– Some scales can recalculate

• Paint can label– Contains safety information– Lists paint part number– May attach printout of formula


Paint Reduction

• Stirring– Paint must be uniform before reduction– Heavier paint components settle out– Scrape solids off bottom if settled– Do not shake waterborne paint– Seal lid in place– Unsealed lid allows solvents to escape


Paint Reduction (Cont.)

• Reducer type– Match to spray booth temperature

• 60– 70F low-temp reducer• 70– 85F mid-temp reducer• Above 85F high-temp reducer



• Hardener type– Temperature rated– Intended usage rated– Surface cure

• Amount of time paint will stay wet • Absorb overspray



• Hardener type– Spot-rated

• Fast surface cure

– Panel-rated• Intermediate surface cure

– Overall-rated• Slow surface cure



• Viscosity– Thickness of

paint– Measure with

viscosity cup– 18 – 22 seconds

for most paints



• Viscosity– High-viscosity value

• Paint too thick

– Low-viscosity value• Paint too thin

– Sprayable range



– Part reduction– Percentage reduction– Combination volume reduction



Volume reduction• Part reduction

– Instructions given as ratio• For example, 4:1 = four parts (units) of one substance

to one part of another substance

– Mixing stick• Contain lines indicating units• Must have straight-sided container



• Part reduction using mixing stick with equal increments marked (4:1:1 mixing ratio)



• Part reduction using dedicated paint mixing stick



• Part reduction– Graduations

• Units on paint mixing stick

– Mixing cup• Has various mixing ratios • Select correct ratio



• Percentage reduction– Uses percent of volume

• Combination volume reduction– Uses both parts and percentage



• Weight reduction– Use scale– Weigh out

components– Produces

desired volume of paint

– Volume mixing ratio cannot be used

Documents

Paint Mixing and Reducing