AirSprayTech Academy Certificate Program

Portable Plural-Component Coating Systems for Contractors

Article 18 of 24

Jobsite Setup, Prestart Inspection, Priming, and Startup

A controlled startup begins before the proportioner is powered, pressurized, or connected to coating material. The contractor must establish a safe work area, confirm the material and equipment configuration, inspect every fluid and power connection, prime each component without cross-contamination, and verify stable operation before production spraying begins.

Startup Is a Controlled Process

Portable plural-component equipment combines two reactive materials at a controlled ratio. The system may also use high fluid pressure, heated materials, solvents, compressed air, electrical power, generators, feed pumps, agitators, and long heated hoses.

A startup error can introduce air, solvent, moisture, old material, or the wrong component into the system. It can also create off-ratio material inside the mix manifold or hose, where the material may cure before the problem is recognized.

The crew should therefore use a written startup procedure for the exact equipment and coating system. Memory and habit are not substitutes for the current equipment manual, coating instructions, safety data sheets, and project requirements.

Establish the Jobsite Before Unloading the Rig

The equipment location affects safety, productivity, hose performance, material temperature, communication, and emergency response. Walk the site with the responsible project representative before positioning the rig.

• Confirm the approved spray area and equipment location.
• Identify classified or potentially hazardous locations.
• Confirm ventilation and air-movement requirements.
• Identify ignition sources and establish the required exclusion zone.
• Locate emergency exits, fire extinguishers, eyewash equipment, safety showers, spill supplies, and first-aid equipment.
• Determine where coating, solvent, waste, and contaminated materials may be stored.
• Protect the rig from traffic, falling objects, weather, overspray, and unauthorized access.
• Provide stable, level support for the proportioner, drums, totes, heaters, pumps, and generators.
• Plan hose routes that minimize sharp bends, crushing, abrasion, heat loss, trip hazards, and vehicle exposure.
• Confirm that emergency responders can reach the work area.

Assign Crew Responsibilities

Plural-component startup should not become a collection of unrelated actions performed by several people. One qualified person should direct the sequence and confirm each hold point.

On a smaller crew, one person may perform several roles. The responsibilities still need to be assigned and understood.

Confirm the Material Before Connecting It

Component identity must be confirmed before opening containers or inserting supply pumps. Packaging color alone is not sufficient identification.

• Confirm the manufacturer and complete product name.
• Confirm Component A and Component B designations.
• Confirm the specified mix ratio and whether it is by volume or weight.
• Record batch or lot numbers and expiration information.
• Confirm that the containers are unopened, undamaged, and properly labeled.
• Check storage and conditioning temperatures.
• Determine whether either component requires agitation or premixing.
• Confirm approved thinning, solvent, flushing, and cleanup materials.
• Review the current product data sheet, application instructions, and safety data sheets.

Prestart Equipment Inspection

Perform the inspection while the equipment is depressurized, isolated from unintended operation, and safe to examine.

Confirm the System Configuration

The equipment must be configured for the material being applied. Confirm:

• Correct pump or meter sizes for the required ratio
• Correct electronic recipe or ratio setting
• Approved pressure and temperature limits
• Correct hose sizes and maximum permitted hose length
• Required static-mixer type, diameter, and number of elements
• Correct whip hose and spray-gun arrangement
• Correct filters, screens, and spray tip
• Approved flush solvent and flushing arrangement
• Required alarm limits and automatic shutdown functions

Do not assume that the configuration used on the previous project is suitable for the current material.

Grounding, Bonding, and Ventilation

Establish grounding, bonding, and ventilation before transferring material, flushing, or spraying. Requirements depend on the materials, equipment, location, and applicable regulations.

• Connect the proportioner to a verified ground as directed by its manufacturer.
• Bond and ground conductive supply, flushing, and waste containers when required.
• Maintain electrical continuity through approved fluid hoses and spray equipment.
• Remove unnecessary plastic, insulating materials, and ungrounded conductive objects from the spray area.
• Start required ventilation before opening or transferring material.
• Confirm that exhaust air will not expose personnel or enter building air intakes.
• Keep unauthorized electrical equipment and ignition sources outside restricted areas.

OSHA spray-finishing requirements address ventilation, grounding, liquid transfer, ignition control, and positive-displacement-pump overpressure protection. Project-specific controls may be more restrictive. :chatgpt-content-reference{index="0"}

Priming the Component Circuits

Priming replaces air, storage fluid, flushing solvent, or previous material with the correct coating component. A-side and B-side circuits must remain isolated until each side has been independently confirmed.

1. Verify valve positions. Confirm that the mix manifold is isolated and that return or sampling lines are directed into the correct labeled containers.
2. Start at minimum practical pressure. Increase pressure only as needed to move material safely through the circuit.
3. Prime the A side independently. Continue until the discharge is free of air, solvent, storage fluid, and foreign material.
4. Prime the B side independently. Use the same controlled process and a separate labeled waste container.
5. Inspect the discharged materials. Confirm color, consistency, temperature, and absence of bubbles or contamination.
6. Monitor supply levels. Never allow a component pump to draw air.
7. Check for leaks. Inspect pumps, filters, valves, hoses, fittings, heaters, manifolds, and sampling outlets.
8. Confirm stable feed. Watch for cavitation, surging, irregular pump movement, or pressure fluctuation.

Prime the Solvent-Flush System

If the equipment uses a separate solvent-flush pump, it must be ready before reactive components enter the mixed-material circuit. A failed or unprimed flush system can allow mixed material to cure in the manifold, mixer, whip hose, or gun.

• Confirm that the solvent is approved for the coating and equipment.
• Confirm that the solvent container and receiving container are properly grounded and bonded when required.
• Inspect the flush pump, hose, regulator, valve, and fluid connections.
• Prime at controlled pressure into an approved receiving container.
• Remove air from the flush circuit.
• Verify that the flush system can deliver material through the intended mixed-material path.
• Relieve pressure and return the valves to their required startup positions.

The current Graco XM operating instructions, for example, direct the operator to prime the solvent-flush pump into a grounded container and remove air from the mix hose and gun before returning the system to a safe condition. The exact procedure must match the equipment in use. :chatgpt-content-reference{index="1"}

Condition and Stabilize the Materials

Material temperature affects viscosity, pressure demand, atomization, hose loss, mixing, and ratio performance. Bring the materials and equipment to the manufacturer’s required operating range gradually.

• Start agitators or recirculation only when permitted by the coating manufacturer.
• Avoid drawing air into the material through excessive agitation.
• Activate heaters in the sequence required by the equipment manufacturer.
• Do not exceed coating or equipment temperature limits.
• Allow drums, pumps, heaters, and hoses sufficient time to stabilize.
• Record actual A-side, B-side, hose, and ambient temperatures where applicable.

A control-panel temperature does not necessarily represent the temperature at every point in a long hose system. Use the monitoring and verification methods required by the approved procedure.

Complete Ratio Verification Before Production

After both component circuits are primed and stable, complete the required calibration confirmation, ratio verification, batch test, or other authorized test. Record the raw measurements and acceptance decision.

A pressure balance is not a substitute for a ratio test. Production must not begin until the system satisfies the coating manufacturer, equipment manufacturer, project specification, and contractor quality-control plan.

If the ratio test fails, stop the startup. Identify and correct the cause, determine whether any mixed material must be removed, and repeat the required verification.

Introduce Components to the Mixing Circuit

Once priming and ratio verification are complete, introduce the components into the mix manifold according to the equipment manufacturer’s sequence.

1. Confirm that the flush valves are closed and the component valves are correctly positioned.
2. Confirm that the correct static mixer, whip hose, gun, guard, and tip arrangement is installed.
3. Remove the spray tip when required for initial displacement and priming.
4. Direct discharge into an approved grounded waste container when required.
5. Begin at the lowest practical pressure.
6. Displace solvent or previous material completely from the mixed-material circuit.
7. Observe the discharged material for uniform color, consistency, temperature, and freedom from air.
8. Relieve pressure before installing or adjusting the spray tip.
9. Install the approved tip and guard, then raise pressure gradually.

Once the components enter the mixing circuit, the material’s usable life is limited. The crew must be ready to spray, monitor, and flush without unnecessary delay.

Conduct a Controlled Test Spray

Do not use the production surface as the first test of startup quality unless the approved procedure specifically permits it. Use a suitable test panel, masked trial area, or other authorized surface.

Evaluate:

• Spray-pattern shape and distribution
• Atomization and edge definition
• Color and visual uniformity
• Pressure stability and pump operation
• Material and hose temperatures
• Leaks, surging, cavitation, or unexpected alarms
• Wet-film thickness when required
• Initial reaction, cure, or hardness when an approved field check is available

Use only the pressure necessary to produce the required pattern and delivery. Excessive pressure increases wear, overspray, rebound, injection risk, and demand on the complete system.

Final Startup Hold Point

Production spraying should begin only after the startup leader confirms:

• The spray area is released and environmental conditions are acceptable.
• The correct materials and lots are connected to the correct component sides.
• The equipment inspection is complete.
• Grounding, bonding, ventilation, and emergency controls are in place.
• Both component circuits and the solvent-flush system are properly primed.
• Temperatures and pressures are stable.
• Ratio verification has passed.
• The test spray has been accepted.
• The crew understands communication signals and shutdown responsibilities.
• Required startup records have been completed.

Record the Startup

A startup record should identify:

• Project, location, date, time, and work area
• Proportioner, pumps, hoses, gun, and equipment identification
• Coating product, components, colors, and lot numbers
• Required ratio and approved equipment configuration
• Ambient, surface, dew-point, and material conditions where required
• A-side and B-side temperatures and pressures
• Ratio-test results and acceptance
• Test-spray observations and wet-film readings
• Alarms, leaks, defects, adjustments, and corrective actions
• Operator, startup leader, quality-control representative, and witness
• Time and location at which production spraying began

The record creates a traceable boundary between material applied under verified conditions and material that may require further evaluation.

Technical References and Further Study

• Graco XM Plural-Component Sprayers—Operation Manual — Includes equipment-specific setup, priming, operation, ratio testing, pressure relief, flushing, and shutdown instructions.
• WAGNER TwinControl Operating Manual — Manufacturer procedures covering installation, commissioning, calibration, operation, flushing, alarms, and maintenance.
• OSHA 29 CFR 1910.107—Spray Finishing Using Flammable and Combustible Materials — Requirements addressing spray areas, ventilation, grounding, liquid handling, ignition control, and related protection.
• OSHA 29 CFR 1926.66—Criteria for Design and Construction of Spray Booths — Construction-industry requirements applicable to covered spray-finishing operations.
• Current coating manufacturer product data sheets, safety data sheets, application instructions, plural-component setup guides, and project specifications.

Manufacturer references are included as technical examples and educational resources. Their inclusion does not constitute a product endorsement. Use the current manual for the exact equipment model, configuration, and software version being operated.

Professional Responsibility

Plural-component equipment may operate with hazardous, reactive, heated, flammable, sensitizing, or extremely high-pressure materials. Follow the coating and equipment manufacturers’ current written instructions, safety data sheets, pressure-relief procedures, ventilation requirements, grounding and bonding requirements, personal-protective-equipment requirements, project specifications, and applicable regulations. Setup and startup must be performed only by trained and authorized personnel.

Copyright © 2026 Azimuth Spray Systems, LLC. All Rights Reserved.

No part of this material may be reproduced, distributed, transmitted, stored, or used in any form without prior written permission from Azimuth Spray Systems, LLC, except for brief quotations used with proper attribution.

AirSprayTech.com – The Finishing Authority®