There’s something you didn’t quite understand? Perhaps you’ve read something from the knowledge base that didn’t click? Here’s a handy list of terms to help you along the spray painting learning curve.
A
Adhesion
Adhesion refers to how well paint sticks to a surface. Poor adhesion leads to peeling, flaking, or chipping.
If a surface isn’t properly cleaned, sanded, or primed, adhesion fails. Smooth or contaminated surfaces are the most common cause, especially when skipping proper prep.
Air Cap
The air cap is the front component of a spray gun that directs airflow and shapes the spray pattern. It plays a major role in atomization.
Different air cap designs change fan width and droplet size. Even a partially clogged air cap can distort the pattern and create uneven coverage.
Air Consumption
The amount of air a tool or spray gun requires to operate properly, usually measured in CFM.
If your compressor can’t meet this demand, pressure drops during use. This is why tools can feel strong at first, then weaken mid-pass.
Air Dryer
A device that removes moisture from compressed air.
As air compresses and cools, water forms inside the system. Without drying, that moisture travels into your paint and causes defects like bubbling or fisheyes.
Air Hose (Compressor Hose)
Transfers compressed air from the compressor to the tool.
Hose diameter and length directly affect airflow. A long or narrow hose can restrict performance even if the compressor is capable.
Air Leak
Unintended air loss in the system, often from fittings or worn connections.
Leaks reduce available pressure and force the compressor to cycle more often, which increases wear and reduces consistency.
Air Pressure (PSI)
Air pressure controls how forcefully paint is atomized and delivered.
Higher pressure breaks paint into finer droplets but increases overspray. Lower pressure improves control but can lead to poor atomization if too low.
Air Regulator
A device that controls and stabilizes air pressure going into the spray gun.
Mounted at the compressor or near the gun, it prevents pressure spikes and keeps the spray pattern consistent over time.
Airflow Restriction
Any limitation that reduces the amount of air reaching the tool.
Often caused by small hoses, restrictive fittings, or undersized couplers. Even one weak point can affect the entire system.
Atomization
The process of breaking paint into fine droplets.
Good atomization creates a smooth, even finish. Poor atomization leads to texture, uneven coverage, and visible defects like orange peel.
B
Basecoat
The color layer applied before clear coat. It provides visual appearance but not protection.
It must be applied evenly, especially with metallics, where uneven passes can change how light reflects off the surface.
Bleeding
When underlying materials or stains show through new paint.
Often happens when fillers, old paint, or contaminants aren’t properly sealed before applying new layers.
Blending
A technique used to fade new paint into existing paint.
Requires controlled spray technique and proper overlap to avoid visible edges or color mismatch.
Bounce-Back
Paint particles that rebound off the surface instead of sticking.
More common at higher pressures or when spraying too close. It increases waste and can create a rough finish.
Build (Coating Thickness)
The total thickness of applied paint layers.
Each coat adds build. Too much traps solvents and causes defects. Too little reduces durability and coverage.
C
CFM (Cubic Feet per Minute)
Measures how much air a compressor delivers.
This is the most important spec for tools and spray guns. If CFM is too low, performance drops under continuous use.
Clear Coat
A transparent layer that adds gloss and protection.
It determines the final appearance and durability. Any imperfections here are highly visible.
Coalescing Filter
A filter designed to remove oil and very fine contaminants from compressed air.
Often used in combination with moisture separators for clean air in painting setups.
Compressor
Supplies compressed air to the spray system.
Performance depends more on airflow consistency than tank size. A stable compressor makes the entire system easier to use.
Condensation
Water that forms inside air lines as compressed air cools.
More noticeable in humid environments or long hose runs. Needs to be removed before reaching the gun.
Contamination
Any substance that interferes with paint (oil, water, dust).
Even small amounts can cause visible defects. Clean air and surface prep are critical.
Coupler (Quick Connect)
Connects hoses and tools quickly.
Low-quality couplers can restrict airflow or leak. High-flow couplers reduce restriction in demanding setups.
D
DA (Dual Action) Sanding Pattern
A sanding motion that combines rotation and oscillation.
Reduces visible sanding marks and creates a more uniform surface for painting.
Dry Spray
Paint that dries before reaching the surface.
Leaves a rough, dusty finish. Often caused by too much distance, high temperature, or fast solvent evaporation.
Duty Cycle
The percentage of time a compressor can run continuously.
Exceeding this limit causes overheating and reduces lifespan. Important for longer work sessions.
E
Etch Primer
A primer designed to bond to bare metal by chemically etching it.
Creates strong adhesion but usually requires additional layers before paint.
Expansion Loss
Air pressure loss caused by expansion over distance.
More noticeable in long hoses or systems with multiple connections.
F
FAD (Free Air Delivery)
The actual usable air output of a compressor.
More accurate than advertised numbers. Real performance is usually lower than stated specs.
Fan Pattern
The shape of the spray coming out of the gun.
Should be even from top to bottom. Uneven patterns often point to air cap or pressure issues.
Feathering
Smoothing the edges of a repair area.
Helps blend transitions and prevents visible lines in the final finish.
Filter (Air Line Filter)
Removes contaminants from compressed air.
Essential for clean spraying. Without it, moisture and oil can reach the paint.
Flash Time
The waiting time between coats.
Allows solvents to escape. Ignoring it can cause bubbling or poor curing.
Fluid Control
Adjusts how much paint flows through the gun.
Balancing fluid with air pressure is key to achieving a proper spray pattern.
Fluid Tip (Nozzle)
Controls paint flow through the gun.
Larger sizes allow thicker materials, smaller sizes provide finer control.
G
Gravity Feed
A spray gun design with a top-mounted cup.
Uses gravity to assist paint flow, improving efficiency and reducing required pressure.
H
Heat Build-Up
Temperature increase during compressor operation.
Higher heat increases moisture in the system and reduces efficiency.
HVLP (High Volume Low Pressure)
Uses high air volume at low pressure.
Improves transfer efficiency and reduces overspray, but requires higher CFM.
I
Inline Regulator
A small regulator mounted near the spray gun.
Allows precise pressure adjustment at the point of use.
K
Kink Resistance
A hose’s ability to resist bending and airflow restriction.
Important for maintaining consistent airflow during use.
L
LPH (Low Pressure High Transfer Efficiency)
Focuses on efficient paint transfer and fine atomization.
Often used in high-end applications where finish quality is critical.
LVLP (Low Volume Low Pressure)
Uses lower air volume and pressure than HVLP.
Easier to run on smaller compressors, but may require more careful technique.
M
Metallic Paint
Paint containing reflective flakes.
Application technique affects how flakes align, which changes the final appearance.
Micron Rating
Indicates how fine a filter is.
Lower ratings capture smaller particles and improve air quality.
Mist Coat
A very light coat used to control metallic orientation.
Helps even out finish without adding significant build.
Moisture Separator
Removes water from compressed air.
Placed in the air line to prevent moisture from reaching the gun.
N
Needle
Controls paint flow inside the spray gun.
Works with the fluid tip. Wear or damage leads to leaks or uneven flow.
Nozzle (Fluid Tip)
Controls paint flow through the gun.
Choosing the correct size is essential for proper atomization.
O
Oil Contamination
Oil entering the air line.
Causes defects like fisheyes and prevents proper paint adhesion.
Oil-Less Compressor
Uses self-lubricating components.
Low maintenance and portable, but often louder and less durable.
Oil-Lubricated Compressor
Uses oil for lubrication.
Runs quieter and lasts longer, but requires periodic maintenance.
Orange Peel
A textured finish resembling an orange surface.
Usually caused by poor atomization, incorrect setup, or improper viscosity. Learn more about identifying and fixing clear coat problems.
Overspray
Paint that misses the surface and becomes airborne.
Leads to waste and can settle on surrounding areas.
P
Pattern Control
Adjusts spray width.
Helps match the spray to the size of the work area.
Pot Life
The usable time of mixed paint before it hardens.
After this time, paint becomes unstable and should not be used.
Pressure Drop
Loss of pressure due to hose length or restrictions.
Becomes noticeable during continuous use and affects consistency.
Primer
Base layer that improves adhesion and surface quality.
Different primers serve different purposes, including filling and sealing.
PSI (Pounds per Square Inch)
Measures air pressure.
Important for setup, but must be balanced with airflow.
R
Reducer
Thins paint for proper spraying.
Different speeds control how fast solvents evaporate.
Regulator (Compressor)
Controls output pressure from the compressor.
Provides a stable starting point for the system.
Runs / Sags
Excess paint flowing downward.
Usually caused by applying too much material or moving too slowly.
S
Sanding Grit
Refers to abrasive particle size.
Lower grit removes material quickly, higher grit smooths the surface.
SCFM (Standard Cubic Feet per Minute)
Standardized airflow measurement.
More reliable than CFM for comparing compressors.
Sealer
Creates a uniform surface before paint.
Helps prevent color variation and improves adhesion.
Solvent Pop
Small bubbles caused by trapped solvents.
Often appears after curing if flash times are ignored.
Static Pressure
Pressure in the system when no air is flowing.
Does not reflect real working conditions.
Substrate
The surface being painted.
Preparation depends on the material (metal, plastic, wood).
T
Tack Coat
A light first coat that improves adhesion.
Helps reduce the chance of runs in later coats.
Tank Capacity
Amount of stored compressed air.
Affects how long tools can run before the compressor cycles.
Transfer Efficiency
How much paint reaches the surface vs wasted.
Higher efficiency means less overspray and better coverage.
Turbine System
A system that generates air without a traditional compressor.
Used in some HVLP setups for consistent airflow.
U
Urethane Paint
A durable paint system commonly used in automotive finishes.
Offers strong resistance to chemicals, UV, and wear.
V
Viscosity
How thick or thin paint is.
Affects atomization, flow, and final finish quality.
W
Water Trap / Moisture Separator
Removes water from compressed air.
Essential for preventing moisture-related defects.
Wet Coat
A full, glossy coat applied after a tack coat.
Should flow smoothly without sagging or running.