Common Coating Terms
Learning the lingo!
Confidential information – not for public use or transmission
Terminology
BASICS
APPLICATION TERMS
COMMON PROBLEMS
Confidential information – not for public use or transmission
Paint vs. Coating?
Paint Coating
› About $20 per gal. › At least $40 per gal.
› Typically for Architectural use, DYI › Commercial, Marine & Industrial
› Aesthetics - decorates and use
beautifies › Corrosion and fire protection
› Limited corrosion protection › Safety (hot surfaces, slips and falls)
› Typically thin film, 1 to 5 mils DFT › Typically 2 – 250 mils DFT
Confidential information – not for public use or transmission
Solids by Volume (SBV) aka: Volume Solids
› The percentage (%) of a coating’s volume that remains
after the solvent evaporates
Example: 75% SBV epoxy
o 75% is solids
o 25% is solvent
Confidential information – not for public use or transmission
VOC (Volatile Organic Compounds)
› That portion of a coating’s formula that is organic and
volatile (organic solvents) – evaporates
› Measured in pounds per gallon (lb./gal.) or grams/liter (g/L)
› Clean Air Act has established emission guidelines for VOC’s
for various generic types and end uses
Confidential information – not for public use or transmission
Coating Thickness
› Thickness measured in mils and/or microns
› One mil = 1/1000 of an inch (0.001”) or 1” = 1,000 mils
› One mil = 25 microns / 25,000 microns = 1”
o Paint = 1 – 4 mils (25 – 100 microns)
o Coating = 2 – 250 mils (50 – 6,250 microns)
o Copy paper = 2 - 6 mils (50 - 150 microns)
o Business card = 10-15 mils (250 -375 microns)
Confidential information – not for public use or transmission
Wet Film vs. Dry Film Thickness
› WFT = Wet Film Thickness
Measured with a wet film gauge
› DFT = Dry Film Thickness (film remaining after solvent
evaporates)
Measured with magnetic pull off and/or electronic gauges
Confidential information – not for public use or transmission
Gloss/Sheen
› That characteristic of a finish that reflects light from its surface
How much shine or sheen the coating exhibits
Per MPI Gloss and Sheen Standards Measured at 60° ranges from 0-100
o Gloss Level 1: Flat Finish (5 units max.)
o Gloss Level 2: Velvet Like Finish (10 units max.)
o Gloss Level 3: Traditional Eggshell (10-25 units)
o Gloss Level 4: Satin (20-35 units)
o Gloss Level 5: Traditional Semi-Gloss (35-70 units)
o Gloss Level 6: Traditional Gloss (70-85 units)
o Gloss Level 7: High Gloss (> 85 units)
Confidential information – not for public use or transmission
Portable Gloss Meter
Confidential information – not for public use or transmission
DOI (Distinction of Image)
› That property of a finish which
describes its ability to reflect an image
with clarity
› Particularly important in automotive
and floor finishes
Largely determined by how well a
coating flows and levels to create a very
smooth surface
It is possible to have two films with the
same gloss level but very different DOI’s
Confidential information – not for public use or transmission
Metamerism
› Different appearance of color
under different light sources
› More pronounced in dark or
neutral colors like gray
› Automotive paint: “flop paint”
or Chameleon paint
Confidential information – not for public use or transmission
Curing
› Thermoplastic Coatings
Dries or cures by solvent evaporation
Can be re-dissolved in its own solvent
› Thermosetting Coatings
Dries or cures by chemical reaction
Two or more components mixed together (catalyzed)
Cannot be re-dissolved
Creates a tougher and more durable film
Confidential information – not for public use or transmission
HAPS (Hazardous Air Pollutants)
› Certain solvents are considered “hazardous”
› HAPS examples – xylene (xylol), toluene (toluol)
› HAPS free solvents – acetone, methyl acetate, PCBTF
Confidential information – not for public use or transmission
Miscellaneous
› DTM = direct to metal
› DTR = direct to rust
› Surface Tolerant = tolerant of less than ideal surface prep
› Moisture Tolerant = cures and adheres to damp surfaces, can
get wet before full cure
› Single Coat = one monolithic coat (but may mean multiple
passes)
› Intermediate Coat = applied over primer or coating
› Topcoat = finish coat
Confidential information – not for public use or transmission
Terminology
BASICS
APPLICATION TERMS
COMMON PROBLEMS
Confidential information – not for public use or transmission
Mix Ratios & Components
› Mix Ratio
Typically the ratio by volume of Part A to Part B. Some coatings have
more components - Parts C, D and …
Part A: typically the resin component
Part B: typically the catalyst or hardener
Part C: typically corrosion inhibitive pigments, filler or aggregates (Zn dust,
MIO, aggregate, etc.)
Confidential information – not for public use or transmission
Mix Ratios & Components cont.
› Epoxies can be
1:1 … 2:1 … 3:1 … 4:1
› Polyurethanes can be
2:1 … 4:1 … 6:1 … 8:1
› Zinc coatings
Ratios by weight
› Single-pack = 1K or one component
› Two-pack = 2K or two components (Catalyze by mixing the two parts together)
NOTE: Don’t mix off ratio or split kits. This may result in improper cure & coating failure!
Confidential information – not for public use or transmission
Pot Life (Working Time)
› The amount of time the coating is workable after mixing all kit components together
› 1K moisture cured urethanes – react with moisture in the air which may decrease pot life
› The end of pot life is usually a loss of rheology
The coating thickens
The coating thins-out
Loss of film build
Increase in heat (exothermic)
Gellation (setting-up … curing)
Warning: the coating will no longer produce the desired properties!
› Pot life may range from seconds to hours
Confidential information – not for public use or transmission
Spray Application
› Batch mix (single leg) › Plural component
For single component coatings For short pot life and very
or batch mix coatings with pot fast cure coatings.
life “Proportioners”
Confidential information – not for public use or transmission
Induction Time (sweat-in)
› The time required/recommended after mixing two-component
coatings to initiate chemical reactions before application
Typically 0 - 30 minutes
More common with higher ratio coatings or low solids materials
Required in cooler conditions
Always read the Product Data Sheet
Confidential information – not for public use or transmission
Dry Times per ASTM D1640
Dry-To-Touch Time Does not leave a fingerprint
Press down hard with thumb: no twisting
Dry-Hard Time
Dry Through or Press down with thumb at maximum pressure and
Dry-To Handle twist
Depends on topcoat; but normally same as dry-to-
Dry-To-Recoat Time
handle
Time for immersion service or chemical exposure
Cure For Service
Often this is complete cure or near-complete cure
How do you measure cure for service?
Solvent Rub Test (ASTM D5402)
or
Thick film coatings may require a Barcol Impressor
Confidential information – not for public use or transmission
Terminology
BASICS
APPLICATION TERMS
COMMON PROBLEMS
Confidential information – not for public use or transmission
Chalking
› Usually results from exposure to Ultra Violet (UV) rays from sunlight
› Typically a powdery (chalky) layer on the surface
› Very gradual erosion of the coating (typically less than ¼ mil, 6
microns per year)
› Erosion of the coating may eventually result in corrosion
› Most coatings eventually chalk … some chalk more quickly than
others
Confidential information – not for public use or transmission
Fading
› Color changes or irregularities in appearance
UV degradation
Chemical attack
Moisture contamination
› Degree of fading dependent on generic type: i.e. aliphatic urethanes
are UV resistant; aromatic urethanes are not
› Dependent on color (reds, blues, greens and yellows vs white)
› Dependent on type of color pigments (organic vs inorganic)
Confidential information – not for public use or transmission
Chalking and/or Fading
Confidential information – not for public use or transmission
Delamination/Peeling
› Loss of adhesion
Often be caused by:
o Improper surface preparation
o Incompatible coatings (alkyd vs solvented epoxy)
o Contamination between coats (chalk, dirt, oil, etc.)
o Exceeded the maximum recoat window (first coat cured too long and
second coat doesn’t adhere)
o Exceeded maximum DFT (solvent entrapment)
o Top coated prior to minimum cure (solvent entrapment)
Confidential information – not for public use or transmission
Delamination/Peeling
Confidential information – not for public use or transmission
Runs/Sags/Curtains
› Excessive flow of coating
Often caused by:
o Excessive film build or spray gun too close to the work
o Low viscosity (too much thinner added)
o Application to cold substrates or cold air
o Surface too hard or glossy to “hold” paint
o Exceeded pot life
o Batch problem – coating does not meet QC
Confidential information – not for public use or transmission
Runs/Sags/Curtains
Confidential information – not for public use or transmission
Orange Peel
› Hills and valleys, “texture”, in a coating resembling an orange
peeling
Often caused by:
o Paint viscosity too high (often with a high solids coatings)
o (High viscosity/insufficient thinning = poor flow and leveling)
o Material too cold
o (low temperature = high viscosity)
o Spray gun too close to surface
o Spray pressure too low: coating does not atomize well
o “Roller stipple” results from application with roller
o Solvent evaporating too fast – coating does not flow and level well
Confidential information – not for public use or transmission
Orange Peel
Confidential information – not for public use or transmission
Overspray and Dry Spray
› Flat sheen and/or rough surface
Often caused by:
o Coating is too dry when it reaches the surface
o Coatings not flowing and leveling well
o Solvents evaporate too fast
o Spray application with pressure too high
o Spray application during hot and/or windy conditions
o Spraying inorganic zincs when its hot and humid
o Spray gun too far away from surface/at angles
o It can be easy to confuse overspray and dry spray with porous or pitted
substrates
Confidential information – not for public use or transmission
Overspray
Confidential information – not for public use or transmission
Cratering
› Small uniform indentations in a coating that look like small
craters
Often caused by:
o Air pockets trapped in wet film
o Coatings drying on surface too fast
o Insufficient flow and leveling of coating
o Incompatible solvents in the coating
Confidential information – not for public use or transmission
Cratering
Confidential information – not for public use or transmission
Fisheyes
› Separation and/or wet film pulling apart exposing coating
or substrate beneath
Often caused by:
o Contamination on substrate (silicone, oil, grease, water etc.)
o Incompatible coatings (latex and/or waterborne coatings over silicone)
o Coating over sealants prior to their proper cure
Confidential information – not for public use or transmission
Fisheyes
Confidential information – not for public use or transmission
Blushing
› Low sheen finish that may appear milky and/or hazy with a
mottled or non-uniform appearance
Often caused by:
o Moisture contamination in the liquid coating or condensation on the wet film
prior to cure
o Incompatible thinners
o Coatings like polyurethanes and polyaspartics (isocyanate cure) can react
with moisture in the air (high humidity) which results in micro-foaming or very
small air bubbles forming in the coating
o May be seen on epoxy coatings after application. This amine blush may feel
slippery, oily or sticky. Can be difficult to detect by visual inspection.
Confidential information – not for public use or transmission
Blushing/Hazing
Confidential information – not for public use or transmission
Epoxy Blush
Confidential information – not for public use or transmission
Wrinkling
› Rough, crinkled surface
Often caused by:
o Top surface of coating drying faster than the underlying coating
o Excessive film build - solvent entrapment
o Application when it’s too hot or windy
o Most common with oil-based (alkyd) coatings that are too thick (they
need oxygen to fully cure) all the way through the coating
Confidential information – not for public use or transmission
Wrinkling
Confidential information – not for public use or transmission
Pinholing
› Tiny holes that often expose the substrate or previous
coating
Often caused by:
o Insufficient spray atomization or insufficient flow and leveling of the
coating
o Substrate contamination
o Porous substrates such as concrete and IOZ
o (Recommend applying mist coat to wet out and displace air and to help
seal prior to applying full coat)
Confidential information – not for public use or transmission
Pinholing
Confidential information – not for public use or transmission
Pinpoint Rusting
› Rusting at pinholes, holidays, valleys or low spots in the
coating
Often caused by:
o Pinholes exposing substrate
o Insufficient coating thickness
o Surface profile is too deep for coating to sufficiently cover peaks
o Sometimes seen with WB primers or DTM’s that can not overcome
surface contaminants
Confidential information – not for public use or transmission
Pinpoint Rusting
Confidential information – not for public use or transmission
Checking
› Narrow breaks in the topcoat that expose the primer or
substrate
Often caused by:
o Poor flexibility of the topcoat
o Excessive DFT
o Excessive service temperature
o Typically seen with alkyd (oil based) coatings
Confidential information – not for public use or transmission
Checking
Confidential information – not for public use or transmission
Cracking
› Deep cracks in the film that expose the substrate or
coatings beneath
Often caused by:
o Excessive film thickness and insufficient dry time between coats
o Limited flexibility of the coating
o Substrate too hot or too cold when spraying
Confidential information – not for public use or transmission
Cracking
Confidential information – not for public use or transmission
Undercutting
› Under film corrosion
Often caused by:
o Typically occurs when metal is corroding beneath the coating and/or at
holidays, pinholes, and breaks in the coating
o Blistering, corrosion and/or delamination of the coating
Confidential information – not for public use or transmission
Undercutting
Confidential information – not for public use or transmission
Pigment Flooding and Float
› Mottled splotchy appearance on the
surface of the coating
Often caused by:
o Surface tension abnormality
o Horizontal separation of different pigments
o Rub up test shows the pigment flocculation
Confidential information – not for public use or transmission
Skinning/Gelling (in container)
› A thick and/or semi-dry layer of material on top of liquid
coating
Often caused by:
o Improper lid seal
o Moisture contamination
o Coating past its shelf life
o Solvent evaporation from top layer (usually from very fast drying
materials)
Confidential information – not for public use or transmission
Skinning/Gelling
Confidential information – not for public use or transmission
Blistering
› Broken or unbroken bubbles in the cured coating
Often caused by:
o Solvent entrapment
o Coating not cured properly
o Oil contamination
o Moisture accumulating beneath the coating
o Soluble salt contamination on the substrate
o Cathodic disbonding
o Coating failure due to incompatible service or chemical exposure
o Can occur immediately after application or take days, weeks or months to
appear
Confidential information – not for public use or transmission
Blistering
Confidential information – not for public use or transmission
Bubbling or Outgassing
› Bubbles forming in wet coating
Often caused by:
o Coating over porous surfaces (concrete, IOZ’s, rust)
o Coating over hot substrates
o Solvent evaporating too fast
o Not necessarily harmful, especially if the coating flows back together
and forms a continuous film
Confidential information – not for public use or transmission
Bubbling
Confidential information – not for public use or transmission
Lapmarks or Flashing
› Variations in appearance in a painted surface Typically
variance in color and/or sheen
Often caused by:
o Inability to keep a “wet edge” while applying coatings
o Especially problematic when coating large surface areas
o Insufficient film thickness to hide the color beneath
o Overspray
o DFT that varies greatly (higher DFT typically = higher sheen)
o Different batch of coating with color or sheen variance
Confidential information – not for public use or transmission
Lapmarks
Confidential information – not for public use or transmission
Questions?
Confidential information – not for public use or transmission
Resources
Tech Service is available!
technicalservice@carboline.com, 1-800-848-4645, M-F 8am-5pm (CST)
Live Chat!
on carboline.com
/company/carboline @carboline @CarbolineCompany @CarbolineCompany @carboline
Confidential information – not for public use or transmission
