CARC Coatings in Defence Finishing and Why Process Discipline Matters
The Standard Is Higher. The Consequences Are Real.
Whether that paintbrush is covering a military vehicle entering a contamination zone or finishing an aircraft parked on the flight line for 2 years of salt air and UV radiation, it’s doing more than making that asset look nice. It’s protecting it. That coating is what separates the equipment from the environment. In the event of a chemical or biological attack, it’s also what distinguishes equipment that can be cleaned up and restored to service from items that have to be written off completely.
CARC coating was built for that kind of world. Chemical Agent Resistant Coating is not simply a paint upgrade. It’s an engineered finishing system that comes with strict performance standards, military specifications governing its application, and qualification standards that most commercial coatings products don’t even meet.
At Versatile Spray Painting, we work with defence contractors, OEMs, and prime suppliers across Canada and the United States. Located in Bolton, Ontario, we’re ISO 9001: 2015 certified, AS9100D certified, registered with Canada’s Controlled Goods Program, and members of the Canadian Association of Defence and Security Industries (CADSI). When it comes to finishing with CARC coating, we have the technical capability AND the compliance infrastructure to get it done right.
In this article, we’ll cover what CARC coating is, how it works, what the specs demand, and why disciplined process control at every step is what separates the best coatings from the worst.
The chemistry of CARC is well proven. What determines whether it actually works in the field is the rigour of the process behind it. This is where finishing partners earn their place on the approved vendor list.
What Is CARC Coating?
CARC stands for Chemical Agent Resistant Coating. The performance requirement is resistance to chemical warfare agents (CWA). CARC surfaces are designed to be non-absorbent. The chemical agent can’t penetrate the coating surface. Instead, it beads up on top of the surface and washes off using conventional military decontamination solutions with no harm to the coating or substrate.
The first CARCs were developed by the US Army in 1974. In 1983, the Army established a formal requirement for CARC on combat vehicles, combat support vehicles, tactical wheeled vehicles, aircraft and critical ground support equipment. Under US Army Regulation 750-1 implemented in 1985, this became mandatory for all tactical equipment. As of 2018, CARC product approvals for the entire Department of Defence are approved by the US Army Research Laboratory (ARL).
Today, CARC is applied to virtually all military defence platforms and equipment, including tracked and wheeled ground vehicles, military rotary-wing and fixed-wing aircraft, artillery pieces, missile systems, generators, the exteriors of shelters, communications vans, water treatment vehicles, and support equipment. Steel, aluminum and plated plastics are among the substrates typically coated with CARC. CARC specifications are also required for vehicle/component refurbishment programs by government contractors. This puts CARC squarely in the realm of new production as well as maintenance, repair and overhaul (MRO) applications throughout the life cycle of a defence platform.
The Chemistry Behind CARC
At its foundation, CARC is built on polyurethane chemistry. It is sometimes described as a military-grade, low-gloss version of high-performance polyurethane. The formulation requirements, however, go well beyond what commercial-grade polyurethanes provide.
Current Formulation Types
The earliest CARC systems used solvent-borne formulations developed in the early 1980s. Over time, environmental regulations pushed the industry toward systems with lower volatile organic compound (VOC) and hazardous air pollutant (HAP) content. Two main formulation types are in common use today:
Moisture-cure urethane (MCU): A single-component system. When isocyanate groups in the coating react with moisture in the air, the film cures. MCU systems offer lower VOC content and eliminate many hazardous air pollutants compared to older solvent-borne formulas.
Two-component water-reducible polyurethane: The most widely used current type. Part A is the resin; Part B is the isocyanate hardener. After mixing, the two components react to form a tightly crosslinked film. The result is excellent chemical resistance, durability, and controlled NIR reflectance. Water-reducible systems also significantly reduce VOC and HAP emissions.
Key Performance Properties
Across both formulation types, CARC systems share a set of performance characteristics that distinguish them from commercial finishes:
Chemical agent resistance: Non-porous surface prevents CWA absorption. Agents bead and are removable with standard decontamination solutions such as DS2 (Decontaminating Solution No. 2).
Low gloss, matte finish: Minimizes reflection and glare that could compromise camouflage effectiveness in the field.
Near-infrared reflectance control: CARC is formulated to reflect NIR light at levels that blend with the surrounding environment, helping defeat thermal and multispectral imaging systems.
Corrosion and environmental resistance: Protection against moisture, salt, UV radiation, abrasion, and temperature extremes across extended service life.
Resistance to decontamination chemicals: The coating must survive repeated exposure to harsh cleaning agents used during decontamination without degrading.
Modern CARC formulations have also been specifically engineered to eliminate chlorinated solvents and benzene-based materials that appeared in older industrial coatings. This matters both for worker safety during application and for environmental compliance in Canadian and U.S. jurisdictions.
The Governing Specifications
CARC is one of the most tightly specified coating families in the world. This is intentional. Every supplier, every applicator, and every finished part must meet the same performance standard regardless of where in the supply chain the work occurs. Key military specifications include:
MIL-DTL-53072: The overarching CARC system standard, governing the complete coating process, including surface preparation, primer selection, topcoat application, and inspection requirements.
MIL-DTL-53039: Covers single-component aliphatic polyurethane CARC topcoats. Includes VOC and HAP compliance requirements.
MIL-DTL-64159: Governs water-reducible, two-component polyurethane CARC topcoats. This is the specification most commonly associated with current-generation systems.
MIL-PRF-22750 and MIL-C-85285: Additional specifications referenced in certain aviation and aerospace defence applications.
Each specification defines requirements for chemical resistance, adhesion, gloss level, dry film thickness, colour, spectral reflectance, and environmental performance. The military also maintains a Qualified Products List (QPL), which identifies approved material suppliers whose products have been tested and verified by the Army Research Laboratory. CARC may only be procured from QPL-approved suppliers.
For defence programmes in Canada, CARC requirements typically follow the same U.S. military specifications, particularly on equipment procured under bilateral defence agreements or NATO-aligned frameworks. Applicators working within Canada’s Controlled Goods Program must also maintain the registration, access controls, and personnel screening required under that regulatory framework.
Versatile Spray Painting holds current registration under Canada’s Controlled Goods Program. This is not a box-checking exercise. It is a meaningful compliance obligation that tells defence primes and OEMs that their controlled goods will be handled within a properly governed, government-assessed security environment.
For programme managers and procurement teams: selecting a CARC applicator that holds Controlled Goods registration in Canada removes a significant compliance risk from your supply chain. It also shortens the supplier approval process for programmes that require it.
The CARC System: Pretreatment, Primer, and Topcoat
CARC is not a product you apply in a single step. It is a finishing system, and the performance of the topcoat depends entirely on the integrity of what comes before it. Understanding the system is essential for anyone evaluating a CARC finishing partner.
Pretreatment: The Foundation Everything Else Rests On
Surface preparation is where CARC coating either works or fails before the first drop of topcoat is ever applied. The substrate must be clean, dry, and correctly profiled to allow the primer to bond. Any contamination left on the surface, whether it is residual oil, mill scale, rust, blast media, or even a fingerprint, will undermine adhesion and compromise the entire coating system.
Standard pretreatment approaches include abrasive blasting to achieve the correct surface profile, chemical cleaning and degreasing, and substrate-specific treatments such as chromate conversion coating (also known as chem film or Alodine) on aluminum parts. The specific pretreatment required depends on the substrate material, the primer being used, and the requirements of the governing specification.
Failures traced back to inadequate surface preparation rarely show up at final inspection. They show up months later as blistering, delamination, or early corrosion. By then, the parts are in service, and the rework cost is far higher than the cost of doing the preparation properly in the first place.
Primer: Corrosion Protection and the Bond Beneath the Topcoat
Epoxy primers are standard in CARC systems. They provide corrosion protection for the substrate and create the properly prepared surface the CARC topcoat needs to achieve durable adhesion. For parts with complex geometries or recessed areas, electrocoat (e-coat) primers are particularly effective. E-coat delivers consistent film build across intricate shapes and provides excellent corrosion resistance as a base for CARC topcoats.
The primer film thickness must be controlled within the specified range. Too thin, and corrosion protection is compromised. Too thick and the combined system film build may push outside tolerances, particularly on precision parts where dimensional fit matters.
CARC Topcoat: Where Specification Compliance Becomes Visible
The topcoat is applied over a fully cured primer. At this stage, application method, environmental conditions during spray, and dry film thickness all directly affect whether the final coating meets the specification.
Automated and robotic spray systems produce significantly better thickness consistency than manual application, particularly across high volumes. Manual application can meet specifications when performed by qualified operators with calibrated equipment and documented technique, but it is inherently more variable. The choice of application method should reflect the programme’s volume, complexity, and quality requirements.
Why Process Discipline Is Not Optional
This is the section that most separates an experienced defence finishing partner from a general industrial coater who has applied for an approved vendor listing. The specifications are clear. The chemistry is established. What varies between applicators is whether the process behind the coating is actually followed, every time, on every job.
Film Thickness Control
Incorrect dry film thickness is one of the most commonly cited causes of CARC coating failure. Both under-application and over-application are defects. Under-application leaves the surface vulnerable to chemical penetration and accelerated corrosion. Over-application causes adhesion problems through internal coating stress, and on tight-tolerance parts, it can affect dimensional fit.
The solution is calibrated spray equipment, trained and qualified operators, film thickness measurement using calibrated gauges at multiple points across every part, and documented results. Thickness measurement at final inspection only is not sufficient. It confirms the outcome but does nothing to control the process.
Environmental Control During Application
Temperature, relative humidity, and dew point all affect how CARC cures. Two-component water-reducible systems, which are the most widely used current formulation, are particularly sensitive to humidity during application and cure. Applying these coatings outside the acceptable environmental window produces a film with compromised crosslink density, which directly reduces chemical resistance.
A properly equipped spray booth with monitored and controlled temperature and humidity is a process requirement for CARC finishing work. If conditions fall outside the acceptable range, the application must stop. There is no exception to this.
Mix Ratio Accuracy
Two-component CARC systems require the resin and isocyanate hardener to be mixed at the correct ratio before application. Even a small deviation from the specified ratio affects crosslink density in the cured film. Reduced crosslink density means reduced chemical resistance. Since chemical resistance is the primary reason CARC exists, a coating applied at the wrong mix ratio fails at its core purpose even if it looks acceptable.
Calibrated dispensing equipment, documented batch records, and operator training are the controls that prevent this. A quality system that cannot produce a mix ratio record for every batch of CARC applied is not a quality system adequate for defence programme work.
Pot Life Management
Once a two-component system is mixed, it has a defined usable life called pot life. Beyond that window, the material has already begun to cure. Applying it produces a film with compromised properties that may pass visual inspection but will not perform to specification under chemical exposure or field conditions. Process discipline means strict batch timing, no carryover of mixed material from one session to the next, and documented disposal of any material that exceeds pot life.
Cure Conditions and Verification
The cure environment matters as much as the application environment. Temperature and humidity during the cure period affect how completely the coating crosslinks. Forced curing in controlled booths is common in production settings and improves consistency. Full cure must be achieved before parts are handled, packed, or shipped. Handling partially cured parts damages the coating and often cannot be detected until failure occurs in service.
Inspection at Every Stage, Not Just the End
Final inspection is not a quality programme. It is the last verification point in one. By the time a part reaches final inspection, every process step before it has either been executed correctly or it has not. Inspection can confirm the result. It cannot repair a poorly controlled process.
Effective inspection for CARC finishing includes dry film thickness measurement at multiple points, adhesion testing using cross-cut or pull-off methods, gloss level verification, visual inspection for defects, and periodic salt spray and humidity resistance testing to validate ongoing process performance. All results should be documented and retained as part of the job record.
At Versatile Spray Painting, full QA inspection and reporting is part of every job. Buyers do not need to chase documentation after the fact. The record is built as the work is done, and it is ready when the shipment is.
Health, Safety, and Environmental Compliance
CARC application uses isocyanate-reactive materials in two-part polyurethane chemistries. Isocyanates are known respiratory sensitizers. Repeat exposure after sensitization can cause serious reactions from minute exposures. This isn’t hypothetical. This is a well-understood occupational health risk that must be controlled with engineering controls, properly designed and maintained spray ventilation, and correct respirators for all personnel in the spray environment.
Applicators must follow all applicable OSHA and NIOSH guidelines in the United States and equivalent federal and provincial guidelines in Canada. This includes having written hazard communication programs, up-to-date SDS’s, and documented health and safety training for all employees performing CARC application and handling.
On the environmental side, modern water-reducible CARCs dramatically reduce VOC and HAP emissions when compared to the solvent-borne systems they replaced. Nevertheless, CARC operations still produce waste streams that include spent spray booth filters, overspray waste, and used mixing pots that must be managed and disposed of according to hazardous waste regulations in both the U.S. and Canada.
Environmental compliance isn’t a separate goal from operational discipline. It’s part of the same objective. An applicator that cares enough to properly manage its hazardous waste, maintain its air permits and train its employees on proper chemical handling is the same applicator that will take care to control its coating process and produce repeatable, compliant finishes.
Quality Systems, Documentation, and Traceability
Defence programmes require more than a good coating. They require proof that the process was followed on every job, every time. Quality management systems are the framework that makes that proof possible.
CARC applicators serving defence programmes are expected to operate under a recognized quality management system. ISO 9001:2015 sets the baseline. For aerospace and defence work specifically, AS9100D is the applicable standard. AS9100D builds on ISO 9001:2015 and adds requirements specific to the regulated, safety-critical environment of aerospace and defence manufacturing.
Versatile Spray Painting holds dual certification to ISO 9001:2015 and AS9100D. This certification is current and independently audited. It covers all processes within our facility, not just the coating line. For buyers evaluating suppliers, an AS9100D certification signals that the quality system has been assessed by an accredited body and found to meet the rigorous requirements of the aerospace and defence standard.
Within that quality system, documentation discipline covers materials traceability (QPL-compliant materials with batch records), application records (environmental conditions, operator identification, equipment calibration status), inspection records (thickness measurements, adhesion results, visual findings), and non-conformance reporting. All of this is retained and available for customer review, audit, or programme closeout.
Versatile Spray Painting is also investing in ERP-driven traceability systems, planned for further development through 2026. This investment reflects a commitment to keeping pace with the documentation and reporting expectations of the programmes we serve, including primes and OEMs who require real-time visibility into their supply chain.
What to Look For in a CARC Finishing Partner
If you are sourcing CARC coating services for a defence programme, the evaluation questions you ask before awarding work are more important than the questions you ask at final inspection. Here is what to ask:
- Specification knowledge: Can they identify the correct MIL-DTL specification for your programme? Do they understand what it requires at each stage of the process?
- Material compliance: Are they using QPL-approved materials? Can they provide batch records and certificates of conformance?
- Process controls: How do they control and document environmental conditions during application? What equipment do they use to measure film thickness? How do they manage pot life?
- Quality system: Are they certified to ISO 9001:2015 and AS9100D? Can they provide full documentation packages with every job?
- Controlled Goods registration (Canada): If your programme involves controlled goods, are they registered under Canada’s Controlled Goods Program? Is that registration current?
- ITAR capability: For programmes with ITAR-sensitive components, does the applicator have the workflows and access controls to handle that work in compliance?
- Health and safety programme: Do they have documented controls for isocyanate exposure? Is their spray facility properly ventilated and equipped?
- Logistics capability: Can they manage white-glove pickup and delivery across North America? Can they handle full assemblies, not just individual parts?
That last point matters more than many buyers realize. For programmes that include sensitive components or parts that cannot be disassembled for finishing and reassembled at the buyer’s facility, an applicator who handles full assemblies with appropriate care is required. It is the only path.
Versatile Spray Painting offers white-glove pickup and delivery across North America and full assembly handling as standard capabilities, not add-on services. Programme managers working on tight schedules, across long distances, with sensitive equipment, should not have to solve logistics on top of finishing compliance. We handle both.
Common Misunderstandings About CARC
“Any good polyurethane topcoat in the right colour will do.”
Commercial polyurethane coatings do not meet NIR reflectance, chemical resistance, or QPL requirements. Colour match is not specification compliance. There is no acceptable substitute for QPL-approved CARC materials on defence programmes.
“More thickness means more protection.”
Over-application is a defect. It causes adhesion failures, creates internal coating stress that leads to cracking or delamination, and on precision parts, it affects dimensional fit. Thickness must stay within the specified range, bounded on both ends.
“CARC application is the same as industrial spray painting.”
The spray equipment may look similar. The discipline is not. Specification compliance, QPL material requirements, environmental controls, mix ratio management, documentation obligations, quality system requirements, health and safety controls, and Controlled Goods compliance make CARC finishing a fundamentally different operation from general industrial coating work.
“Our supplier passed final inspection, so the process must be fine.”
Final inspection confirms the visible result. It does not confirm the process. A coating applied outside environmental spec, with an off-ratio mix, or on an inadequately prepared surface, may pass visual inspection and film thickness checks while carrying hidden failure modes that will emerge in service. Process compliance has to be built in, not inspected in at the end.
Why This Matters for Canadian Defence Programmes
Canada’s defence industrial base has been growing its capability and its profile within NATO and bilateral defence relationships with the United States. Canadian finishing suppliers who hold the right certifications, operate within the Controlled Goods framework, and can deliver CARC to U.S. military specifications are increasingly valuable to both Canadian primes and U.S. OEMs looking to qualify Canadian supply chain partners.
CADSI membership, which Versatile Spray Painting holds, connects Canadian defence suppliers with the broader network of Canadian and international defence industry relationships. For buyers sourcing within Canada, this signals a supplier that is engaged in the defence community and committed to operating at the standard the industry expects.
For programmes that span the Canada-U.S. border, the combination of ITAR-capable workflows, Controlled Goods registration, and white-glove cross-border logistics means a programme manager in either country can engage Versatile Spray Painting as a single-source finishing partner without worrying about the compliance complications that come with sourcing across jurisdictions.
The Bottom Line
CARC coatings have protected military equipment for decades. The specifications are thorough. The testing protocols are rigorous. The materials are well understood. None of that matters if the process behind the application is not executed with the same discipline the specification demands.
Surface preparation, primer selection and application, environmental control during spray, mix ratio accuracy, pot life management, cure verification, and documented inspection at every stage: these are the steps that turn a specification requirement into a coating that performs in the field. Skipping or shortcutting any of them is where field failures begin.
For defence contractors, OEMs, and programme managers sourcing CARC finishing services in Canada or the United States, the question is not just whether a supplier can apply CARC. It is whether they have the certifications, the process controls, the documentation systems, and the operational capability to deliver compliant, traceable, on-schedule work that holds up under programme scrutiny.
Versatile Spray Painting, located in Bolton, Ontario, is built for exactly that standard. ISO 9001:2015 and AS9100D certified. Canada Controlled Goods Program registered. CADSI member. ITAR-capable. White-glove pickup and delivery across North America. Full assembly handling. Full QA reporting on every job.
If you are working on a defence finishing programme and need a partner with the credentials and the process discipline to deliver, contact Versatile Spray Painting at versatilespray.com or reach out directly to discuss your project requirements.
No Comments