Why the UK Heatwave Is Not Stopping Our Conformal Coating Process

One of the most important lessons when training staff on Parylene is that the deposition chamber is only one part of the process.

New operators often focus on the machine because it is the most visible and technical stage. However, many Parylene failures are caused before the chamber door is closed or after the coating run has finished.

Cleaning, handling, masking, loading, demasking, inspection and traceability are often the areas that decide whether the coating succeeds in production.

The common training mistake

It is easy to train staff as machine operators rather than process technicians.

If the training begins with recipes, buttons, vacuum readings and deposition times, operators may assume that Parylene quality is mainly controlled by the chamber cycle.

This distinction matters because a technically successful coating run can still produce unacceptable parts if the assemblies were contaminated, poorly masked, incorrectly loaded or damaged during demasking.

Where failures often begin

Parylene vapour will generally deposit wherever it can reach. That is both its strength and its risk.

Staff need to understand that the process is sensitive to preparation and control. Typical training focus areas should include:

• cleanliness and contamination control before coating
• safe handling of assemblies before and after deposition
• masking design, masking integrity and keep-out protection
• fixture loading and vapour access
• demasking without lifting or damaging the coating edge
• inspection criteria and evidence recording

The aim is not to overload new staff with theory. The aim is to show them where real production risk usually enters the process.

A better starting message for operators

A useful opening message is simple:

This helps operators understand why apparently small steps matter.

A fingerprint, poor mask edge, loose fixture, blocked vapour path or rushed demasking step can undermine an otherwise stable Parylene run.

What good Parylene training should create

Good Parylene training should create staff who understand cause and effect across the whole process.

Operators should be able to recognise when something is not ready for coating, when a masking approach is risky, when loading may affect coating access and when inspection evidence is not strong enough.

That is the difference between a person who can run a machine and a person who can help protect a controlled coating process.

Related guidance

For deeper technical guidance, see the Parylene manufacturing process control article and the Parylene troubleshooting workflow.

For practical support, see Parylene training and support.

Why Choose SCH Services?

SCH Services supports Parylene coating as a controlled manufacturing process, not just a coating application.

• Practical operator and engineer training
• Support with masking, handling, inspection and process control
• Experience in coating services, equipment and production troubleshooting
• Clear guidance for moving from trial work into repeatable production

If you need help training staff or improving Parylene process control, contact SCH Services to discuss the application.

This article is general technical guidance only. Parylene coating processes, inspection criteria and production controls should always be validated against the assembly design, customer requirements, applicable standards and qualification testing.

When engineers evaluate ESD coatings, the discussion often starts with electrical performance.

Questions typically focus on surface resistivity, dissipative performance, ATEX requirements, conductivity ranges and long-term electrical stability.

These are all important considerations. However, many ESD coating projects fail before any meaningful electrical testing takes place.

The reason is simple. The coating never properly adheres to the substrate.

In practice, poor adhesion is often a greater risk than poor electrical performance. A coating that does not remain attached to the surface cannot deliver stable dissipative performance, regardless of how impressive the resistivity data may appear on a datasheet.

The Assumption That Creates Problems

Many projects begin with a requirement such as:

• Meet a dissipative resistance range.
• Support ATEX compliance objectives.
• Maintain performance outdoors.
• Provide long-term static control.

The immediate reaction is often to compare coatings and electrical specifications.

However, a more important question is frequently overlooked:

What exactly is the coating being applied to?

Without understanding the true surface material, selecting an ESD coating becomes largely guesswork.

Reality Check: A coating that achieves the correct surface resistivity but fails adhesion testing has already failed the application.

The Surface Matters More Than The Core Material

A common engineering description is simply:

• It is ABS.
• It is plastic.
• It is an outdoor enclosure.

From a coating perspective, these descriptions are often insufficient.

The coating only interacts with the surface it physically touches. It does not interact with the bulk material hidden beneath.

Two components may both be described as ABS, yet one may have an acrylic cap layer, another may use ASA, while another may include mould release residues or additional surface treatments.

Each surface can require a different adhesion strategy, primer selection or preparation process.

This is why experienced coating engineers often spend more time understanding the substrate than selecting the coating itself.

A Real Engineering Example

A recent dissipative coating project involved an outdoor electronics enclosure requiring long-term environmental durability and static control performance.

The component was initially described as UV-capped ABS.

At first glance this appeared straightforward. However, further investigation showed that the coating surface was actually a PMMA (acrylic) cap layer applied over the ABS substrate.

This discovery immediately changed the technical discussion.

The project focus moved away from resistivity targets and towards coating compatibility, primer selection and adhesion performance.

Only after the surface material had been properly identified could a coating system be selected and evaluated with confidence.

The resulting adhesion performance was excellent, but that result was only achieved because the substrate was correctly identified before coating selection began.

Had the PMMA cap layer been overlooked, the project could easily have followed a very different path.

The Correct Engineering Workflow

Many coating projects follow the wrong sequence:

• Select coating.
• Apply coating.
• Test coating.
• Investigate failures.

A more reliable engineering workflow is:

1. Identify the surface material.
2. Understand the operating environment.
3. Select the appropriate primer strategy.
4. Validate adhesion.
5. Confirm electrical performance.
6. Assess long-term durability.

While this approach may appear slower initially, it usually reduces development time, testing costs and project risk.

What Should Be Confirmed Before Any ESD Coating Trial?

Before evaluating any dissipative coating system, engineers should ideally understand:

• Surface material and chemistry.
• Presence of cap layers or coatings.
• Surface treatments or mould release agents.
• Environmental exposure conditions.
• UV exposure requirements.
• Temperature range.
• Abrasion requirements.
• Target electrical performance.

These factors frequently determine coating success long before formal electrical testing begins.

Need Help Qualifying an ESD Coating?

Whether you are developing a new product or qualifying an existing component, identifying the substrate is often the first step towards a successful static control solution.

SCH Services supports customers with coating selection, adhesion assessment, coating trials and engineering validation for dissipative and anti-static applications.

• How to Choose the Right Static Control Approach
• ProShieldESD Coating Platform
• Static Dissipative vs Conductive Coatings

Why Choose SCH Services?

SCH Services supports manufacturers, engineers and product developers with coating selection, application development, process optimisation and production implementation.

• Independent technical guidance based on application requirements.
• Coating trials, validation and engineering support.
• Experience across electronics, industrial equipment, aerospace and specialist applications.
• Access to conformal coatings, parylene coatings, nano coatings and static control technologies.

Disclaimer: This article provides general technical guidance only. Coating performance depends on substrate, surface condition, operating environment, application method and validation requirements. Final material selection and qualification should always be verified through appropriate testing and engineering assessment.

Water resistance is often misunderstood in electronics protection. A coating may cause water to bead, shed liquid quickly or allow a powered demonstration board to keep working during short-term immersion, but that does not automatically mean the assembly is protected against corrosion.

Corrosion protection depends on a different set of behaviours. It requires control of ionic contamination, moisture pathways, electrochemical activity, coating continuity, edge coverage, residues, drying conditions and the exposure environment over time.

This distinction is especially important when evaluating ultra-thin functional coatings, hydrophobic coatings, nano coatings and surface-energy treatments. These technologies can be extremely useful, but they should not be judged using the same assumptions as thicker barrier coatings or Parylene systems.

For a related explanation focused specifically on hydrophobic surface behaviour, see Why Hydrophobic Coatings Don’t Protect Electronics.

Water resistance describes liquid behaviour at the surface

Water resistance normally describes how liquid water interacts with the visible surface of a coating or material. This may include beading, roll-off, reduced wetting, fast drainage or short-term resistance to water penetration.

These properties are usually controlled by surface energy, surface chemistry, coating morphology and the way water contacts the treated surface.

For a wider explanation of the difference between surface-function behaviour and true environmental barrier protection, see Surface Energy vs Environmental Barrier Protection.

For some applications, surface water behaviour is exactly what matters. Examples include splash shedding, condensation reduction, optical surfaces, housings, sensors and assemblies where thickness must be kept extremely low.

However, water resistance alone does not confirm that the coating can prevent electrochemical failure, leakage current, corrosion products or long-term degradation.

Corrosion protection is a system problem

Corrosion on electronics is rarely caused by water alone. It normally requires moisture, ionic contamination, conductive pathways, exposed metal and an electrical or electrochemical driving force.

A coating may repel bulk water but still allow corrosion if residues remain under components, if edges and leads are exposed, if the coating is discontinuous, or if moisture can sit in gaps where it cannot evaporate easily.

Important corrosion factors include:

• Ionic contamination: flux residues, salts, process residues or handling contamination can create conductive paths.
• Moisture duration: short wetting events behave differently from long-term damp exposure or repeated condensation cycles.
• Electrical bias: powered electronics can drive electrochemical migration and corrosion mechanisms.
• Coating coverage: thin films may behave well on open surfaces but perform differently around edges, leads, vias and component gaps.
• Drying behaviour: trapped water under components or within residues can be more damaging than visible water on top of the board.

This is why corrosion protection must be validated using realistic exposure conditions, not only visual water behaviour.

Why powered water demonstrations can be misleading

Demonstrations where electronics continue working under water can be useful to show short-term insulation, water shedding or surface treatment behaviour. They are not the same as a corrosion qualification test.

A board may operate during a short demonstration and still fail later because corrosion is time-dependent. The most important damage may occur after the demonstration, during drying, during repeated cycling or when contaminants remain active on the surface.

For this reason, SCH treats water demonstrations as screening or communication tools rather than final evidence of coating reliability.

They can form part of an evaluation, but they should be supported by insulation resistance testing, humidity exposure, condensation testing, salt or contaminant exposure where relevant, and post-test inspection.

Where ultra-thin coatings can still be valuable

None of this means ultra-thin coatings, hydrophobic treatments or nano coatings are weak technologies. It means they must be used for the right protection mechanism.

Ultra-thin functional coatings can be valuable where the objective is to modify the surface without adding meaningful thickness. They may help reduce wetting, reduce liquid retention, protect optical or RF-sensitive assemblies, support drainage, or provide light-duty environmental resistance where conventional coating build would create problems.

For RF-sensitive electronics specifically, see RF Transparent Coatings for Electronics & Antennas.

They are particularly relevant where:

• coating thickness must be extremely low;
• connectors, contacts, tolerances or optical surfaces cannot tolerate conventional coating build;
• water shedding or reduced surface wetting is the main requirement;
• RF, LED, sensor or precision component performance must not be affected;
• the exposure is controlled and validated against the real application.

For a wider explanation of this distinction, see Surface Function vs Barrier Function Coatings and What Is an Ultra-Thin Functional Coating.

The key is to define whether the application needs surface function, barrier protection, corrosion resistance, dielectric protection or a combination of these behaviours.

In many practical applications, the solution is not purely a surface treatment or a full environmental barrier. Transitional film-forming coatings can provide an intermediate route where limited film continuity and environmental support are needed without moving fully into traditional conformal coating thicknesses.

When water resistance is not enough

Water resistance should not be treated as a substitute for corrosion protection where the assembly is exposed to aggressive or uncontrolled environments.

This includes applications involving ionic contamination, outdoor exposure, condensation cycles, industrial atmospheres, powered operation under humidity, salt exposure, cleaning residues or long-term damp storage.

In these cases, a stronger barrier strategy may be needed:

• conformal coating where broader PCB environmental protection is required;
• Parylene where highly uniform dielectric and barrier coverage is needed;
• selective masking and process control where only certain areas can be coated;
• hybrid strategies where surface-function coatings support but do not replace a barrier system.

For comparison, see conformal coating solutions and advanced functional coatings.

The correct coating choice depends on the failure mechanism being controlled, not only on whether water beads on the surface.

Practical selection question

Before selecting an ultra-thin coating, ask one simple question: are we trying to change how the surface behaves, or are we trying to prevent corrosion over time?

If the answer is surface behaviour, an ultra-thin functional coating may be a good route. If the answer is corrosion protection, the coating must be validated as part of a full environmental protection system.

These types of coatings are often selected where thickness-sensitive RF, optical, sensor or precision assemblies cannot tolerate conventional barrier coating build.

This is the difference between a useful coating demonstration and a reliable production coating specification.

Why Choose SCH Services?

SCH Services supports electronics manufacturers with coating selection, process development, application trials and production coating services across conformal coatings, Parylene coatings and advanced functional coatings.

We help customers separate coating claims from real process requirements by reviewing the application, exposure conditions, masking limits, inspection route, coating thickness and validation method.

• Technical coating experience: practical support across conformal coating, Parylene and ultra-thin functional coating applications.
• Process-led approach: coating selection based on failure mechanism, production reality and validation evidence.
• Application support: assistance with trials, masking, inspection, coating thickness and process control.
• Production capability: subcontract coating services and engineering support for specialist electronics protection requirements.

To discuss whether water resistance, corrosion protection or an ultra-thin functional coating is the right route for your application, contact SCH Services for technical support.

This article is provided as general technical guidance only. Coating selection, corrosion protection and environmental reliability decisions should always be validated against the relevant application requirements, operating environment, standards, qualification tests and customer specifications.

Coating thickness is often treated as a simple measure of protection. The assumption is that a thicker coating must provide better environmental protection, stronger insulation and greater reliability.

That can be true in many conventional conformal coating applications, but it is not a universal rule. On complex electronics, adding more coating can also introduce new risks.

In some situations, a thinner coating can protect better because it interferes less with the assembly, flows more effectively into critical areas, reduces masking burden and avoids some of the failure modes associated with excessive film build.

In many modern electronics assemblies, the engineering challenge is no longer maximum coating thickness, but achieving the required protection with minimum interference. This is explored further in Why Ultra-Thin Coatings Change the Protection Conversation.

Why thickness can become a problem

Thicker coatings can be useful when a robust barrier is required, but excessive or unsuitable film build can create problems around components, connectors, fine-pitch devices and mechanical interfaces.

Common problems can include pooling, bridging, cracking, trapped contamination, poor edge behaviour, stress on delicate parts and increased rework difficulty. Excessive or poorly controlled coating build can also increase the risk of bubbles and pooling defects, coating cracking and masking-related process variation where complex keep-out areas are involved.

This is why coating selection should start with the assembly, failure mechanism and exposure conditions rather than with a fixed belief that more film build is always safer.

For a wider explanation of this coating-selection logic, see Surface Function vs Barrier Function Coatings.

Where thinner coatings can help

Thin coatings can be useful when the design has sensitive areas that do not tolerate heavy coating build. This is especially relevant where the coating must protect without changing how the product works.

Thin does not mean weak

A thin coating should not automatically be treated as a weak coating. In many applications, the protection mechanism matters more than the physical film thickness. Some coatings protect by changing surface interaction, reducing wetting, improving chemical resistance, limiting contamination adhesion or maintaining surface function with minimal interference.

This is different from relying only on physical thickness as the main protection mechanism. The coating may be thin, but the protection mechanism may still be highly relevant to the application.

For deeper context, see Surface Function vs Barrier Function Coatings and What Is an Ultra-Thin Functional Coating?.

When thicker coatings are still the right answer

This does not mean thin coatings are always better. Many assemblies still need conventional conformal coatings, Parylene coatings or thicker barrier systems to provide insulation, coverage and environmental separation.

The mistake is not using a thick coating. The mistake is assuming thickness alone proves suitability.

For this reason, thin coatings and thick coatings should be compared by function, risk and qualification evidence rather than by thickness alone. In many applications, the key distinction is between surface interaction and true environmental barrier performance. See surface energy vs environmental barrier protection.

This is also why water repellency should not be treated as proof of corrosion resistance, environmental isolation or long-term electronics reliability. See Why Water Beading Is Not Proof of Electronics Protection for more context.

What should be validated

Any coating thickness decision should be validated against real use conditions. This may include electrical performance, insulation resistance, condensation behaviour, humidity exposure, chemical resistance, optical performance, RF performance and coating coverage.

For ultra-thin, hydrophobic or functional coatings, validation should prove that the surface effect or low-interference behaviour actually reduces the failure risk. For barrier coatings, validation should prove that film build, coverage and insulation are sufficient.

Related context is available in What Is an Ultra-Thin Functional Coating?, Why Water Beading Is Not Proof of Electronics Protection and Ultra-Thin Coatings.

Why Choose SCH Services?

SCH Services supports coating selection, coating trials, process development and production coating for electronics where protection, reliability and manufacturability all need to be considered together.

• Practical coating experience: SCH works across conformal coating, Parylene and advanced functional coating processes.
• Process-led decision support: coating selection is based on application risk, production method and validation requirements.
• Trial and production capability: SCH can support early evaluation, sample coating, process definition and subcontract coating routes.

Disclaimer: This article is provided as general technical guidance only. Coating selection, process design and product suitability must be validated against the relevant application requirements, operating environment, customer specifications and qualification tests.

Water beading is visually persuasive. When droplets sit on a coated surface instead of spreading, it is easy to assume the electronics underneath are protected.

That assumption can be risky. Electronics protection is not proven by a surface effect alone. Real protection depends on contamination, coverage, edge behaviour, coating continuity, operating voltage, exposure time and the environment around the assembly.

Hydrophobic and ultra-thin coatings can be useful, but water repellency should not be confused with full conformal coating performance or long-term reliability validation.

Why water beading can mislead

Water beading shows that a surface has low surface energy. It does not automatically show that the coating is thick, continuous, electrically protective or suitable for long-term exposure.

A droplet test is also usually clean, short and controlled. Electronic assemblies in service may face condensation, ionic contamination, flux residues, humidity cycling, chemical exposure, particulates, trapped moisture and voltage bias.

This is why droplet behaviour is useful as an observation, but weak as a standalone proof of protection.

The difference between repellency and protection

Repellency describes how a liquid interacts with the surface. Protection describes whether the assembly continues to operate reliably when exposed to the actual environment.

These are connected, but they are not the same thing. A coating may show excellent water beading while still needing proper electrical, environmental and process validation.

This is why the distinction between surface function and barrier function coatings matters when selecting protection for electronics. For a deeper explanation of why low surface energy and environmental barrier performance are different engineering behaviours, see surface energy vs environmental barrier protection.

Where hydrophobic coatings are still useful

This does not mean hydrophobic coatings are ineffective. It means they must be used for the right reason and tested against the right failure mode.

Hydrophobic and ultra-thin coatings can be valuable where low film build, reduced masking, optical clarity, low surface energy or reduced wetting are important. They can be especially useful when conventional coating thickness creates a performance or production problem.

The practical question is not whether water beads. The better question is whether the coating solves the specific risk on the specific assembly. For the broader reliability distinction between short-term water behaviour and long-term electronics protection, see why water resistance is not corrosion protection.

For further technical context, see When to Use Hydrophobic Coatings, Why Hydrophobic Coatings Do Not Always Protect Electronics, What Is an Ultra-Thin Functional Coating? and Hydrophobic Coatings.

What should be validated instead

Protection should be assessed using tests and observations that match the real application. That may include electrical performance, insulation resistance, powered exposure, humidity testing, chemical resistance, visual coverage checks and process repeatability.

For electronics, contamination is particularly important. A clean water droplet on a demonstration board is not the same as moisture interacting with residues, flux, salts or process contamination on a powered assembly.

The strongest coating decisions are made by connecting surface behaviour to real reliability evidence.

For a related discussion on thickness assumptions, see Why Thin Coatings Can Sometimes Protect Better Than Thick Ones.

Why Choose SCH Services?

SCH Services supports coating selection, coating trials, process development and production coating for electronics where protection, reliability and manufacturability all need to be considered together.

• Practical coating experience: SCH works across conformal coating, Parylene and advanced functional coating processes.
• Process-led decision support: coating selection is based on application risk, production method and validation requirements.
• Trial and production capability: SCH can support early evaluation, sample coating, process definition and subcontract coating routes.

Disclaimer: This article is provided as general technical guidance only. Coating selection, process design and product suitability must be validated against the relevant application requirements, operating environment, customer specifications and qualification tests.

Traditional conformal coating thinking often starts with film build, coverage and environmental protection. That approach is still valid, but it does not fit every electronic assembly.

Some products need protection without adding meaningful thickness, changing optical output, altering RF behaviour, filling connectors or creating major masking work. In those cases, an ultra-thin coating can change the whole process decision.

The important point is not that ultra-thin coatings replace conformal coatings or Parylene. The point is that they provide an alternative engineering route when conventional coating thickness, masking or dielectric behaviour becomes too intrusive for the product being protected.

Why thickness can become the problem

Film thickness is often treated as a measure of protection, but thickness also brings consequences. It can affect fine-pitch areas, connector zones, LEDs, sensors, RF circuits and assemblies where coating clearance is limited.

In these cases, the coating may technically protect the board but introduce a new production or performance problem.

This is where ultra-thin coating systems become interesting. Many of these systems are used as surface-function coatings, where the goal is to reduce interference while still providing useful surface behaviour or environmental protection. For the wider distinction between surface-function coatings and true barrier coatings, see surface energy vs environmental barrier protection.

Where ultra-thin coatings can be useful

Ultra-thin coatings are most relevant where the assembly has sensitive functional areas that cannot easily tolerate a conventional coating thickness.

The engineering question changes

The traditional question is often: how much coating do we need?

With ultra-thin coatings, the better question is: what level of protection can we achieve without disturbing the product?

That shift matters.

It moves the decision away from simply comparing coating thickness and towards understanding product risk, exposure conditions, required reliability and acceptable process complexity. This is discussed further in Why Thin Coatings Can Sometimes Protect Better Than Thick Ones.

For deeper coating route selection, see Advanced Functional Coatings, Ultra-Thin Coatings and Advanced Functional Coating Services.

What still needs validation

Ultra-thin does not mean automatically suitable. The coating still needs to be tested against the real operating environment, including moisture exposure, chemical exposure, handling, thermal cycling, cleaning processes and electrical performance requirements.

It is also important to avoid overselling water resistance based on simple demonstrations.

Hydrophobic behaviour, water beading and thin-film demonstrations can sometimes create misleading assumptions if the actual failure mechanism has not been validated. See Why Water Beading Is Not Proof of Electronics Protection for more context.

Submersion, condensation, humidity, ionic contamination, powered bias conditions and long-term field exposure are all different reliability problems. For the difference between short-term water behaviour and corrosion reliability, see why water resistance is not corrosion protection.

The best use case is usually where the coating solves a specific process or design conflict that thicker conformal coatings cannot solve cleanly.

Why Choose SCH Services?

SCH Services supports coating selection, coating trials, process development and production coating for electronics where protection, reliability and manufacturability all need to be considered together.

• Practical coating experience: SCH works across conformal coating, Parylene and advanced functional coating processes.
• Process-led decision support: coating selection is based on application risk, production method and validation requirements.
• Trial and production capability: SCH can support early evaluation, sample coating, process definition and subcontract coating routes.

Disclaimer: This article is provided as general technical guidance only. Coating selection, process design and product suitability must be validated against the relevant application requirements, operating environment, customer specifications and qualification tests.

In explosive and defence manufacturing environments, non-sparking tools are widely used to reduce ignition risk from mechanical impact. Materials such as aluminium bronze, beryllium copper, brass, bronze and Monel are commonly selected because they reduce the risk of spark generation when tools are struck, dropped or scraped.

However, non-sparking does not automatically mean electrostatically safe. A tool can be resistant to mechanical sparking and still accumulate, retain or transfer static charge during handling.

This creates an important blind spot in explosive-zone safety: tool safety should be treated as a combined spark-control and static-control problem, not simply as a material selection issue.

The Blind Spot in Explosive Zone Tooling

Non-sparking tools are designed to reduce the risk of ignition from mechanical impact. They do not inherently control electrostatic charge behaviour.

This matters in facilities handling energetic materials, propellants, pyrotechnics, ammunition components, explosive dusts, powders or sensitive assemblies.

Tools are not passive objects in these environments. They are repeatedly handled, moved across surfaces, brought into contact with packaging, used near polymers and often operated in dry processing areas.

That distinction is critical where static electricity is a recognised ignition source.

Explosive Zone Safety Is a Dual-Risk Problem

Tool safety in explosive environments should be viewed as two related but different risks.

Risk Type	Typical Control	Limitation
Mechanical spark ignition	Non-sparking tool alloys	Does not control static charge
Electrostatic ignition	Controlled charge dissipation	Often not considered at tool level

Aluminium bronze, beryllium copper, brass and other non-sparking materials address the mechanical side of the risk.

They do not automatically provide controlled electrostatic behaviour at the surface where operators hold, move and use the tool.

Where Static Charge Risk Can Develop

Static charge risk is most likely to develop where tools are part of repeated manual handling and movement.

• Tools handled with gloves
• Tools moved across benches or trays
• Tools used near polymers, films or packaging
• Tools used around powders, dusts or energetic materials
• Tools used in dry or low-humidity environments
• Tool holders, racks, trays, jigs and accessories used repeatedly in the same process

In these situations, the tool surface becomes part of the electrostatic control problem.

The question is not only whether the tool avoids mechanical sparks. It is also whether the tool surface can dissipate charge in a predictable and repeatable way.

Where ProShieldESD Fits

ProShieldESD can be positioned as a functional surface-safety enhancement for approved non-sparking tools and accessories.

It should not be presented as a replacement for certified tool material selection, hazardous-area classification, grounding, bonding, operating procedures or formal safety validation.

Its value is in helping introduce controlled electrostatic charge dissipation behaviour to frequently handled surfaces.

This may include tool handles, holders, trays, jigs, racks, maintenance accessories, separation pads and other contact surfaces used near energetic materials.

This creates a more complete approach: non-sparking metallurgy plus controlled dissipative surface behaviour.

Why Surface Behaviour Matters Over Lifecycle

In safety-critical environments, a single surface resistance reading is not enough. The surface behaviour must remain stable through handling, cleaning, wear and environmental change.

Filler-loaded conductive coatings can sometimes suffer from uneven conductive pathways, local variation, abrasion-related change or inconsistent performance across the surface.

Filler-free ProShieldESD technology is based on an intrinsically conducting polymer approach, which supports more homogeneous static-control behaviour across the coated surface.

For defence and explosive-zone users, this matters because predictable behaviour over the lifecycle is more important than a one-off headline reading.

Practical Defence Applications

ProShieldESD-coated tool systems may be relevant where approved non-sparking tools and accessories are used near static-sensitive or ignition-sensitive materials.

Area	Example Items	Intended Benefit
Energetic material assembly	Tool handles, holders, trays, torque-tool grips	Reduce static build-up during repeated manual handling
Ammunition and fuze manufacturing	Jigs, fixtures and small-part handling tools	Support controlled charge dissipation near sensitive components
Propellant and pyrotechnic processing	Scrapers, scoops, bench accessories and racks	Lower the risk of charge accumulation on contact surfaces
UXO and EOD support environments	Non-sparking tool grips, cases and separation pads	Add controlled dissipative behaviour to field-handled accessories
Defence electronics with energetic integration	Workbench tools, fixtures and component trays	Support ESD-safe handling alongside explosive-area controls

The strongest applications are not necessarily the tools themselves, but the complete tool-handling system: tools, trays, holders, fixtures, racks and storage interfaces.

Implementation and Validation

ProShieldESD should only be applied after confirming compatibility with the tool substrate, cleaning method, chemical exposure, abrasion level and operating environment.

Validation should be carried out in the actual tool configuration, not only on flat test panels.

• Surface resistance
• Point-to-point resistance
• Resistance-to-ground in the assembled tool system
• Adhesion to the selected tool substrate
• Wear and handling resistance
• Cleaning and solvent resistance
• Humidity stability
• Periodic verification method

It should also be integrated into the wider ESD and explosive-area control programme, including grounding, bonding, conductive flooring, operator footwear, wrist or heel straps where applicable, and documented inspection procedures.

The objective is not to claim that a coated tool becomes explosion-proof. The objective is to improve the control and repeatability of electrostatic behaviour on frequently handled surfaces.

Final Insight

Non-sparking tools solve only part of the ignition-risk problem.

They reduce the risk of mechanical sparks, but they do not automatically control electrostatic charge accumulation or transfer.

In explosive and defence manufacturing environments, this creates a hidden risk interface: the tool surface itself.

ProShieldESD can support a higher-confidence ESD-control surface on approved non-sparking tools and accessories, helping facilities reduce one of the least visible ignition risks: uncontrolled static charge accumulation during manual handling near energetic materials.

Related ProShieldESD Reading

• How to Choose the Right Static Control Approach
• Static Control in Explosive and ATEX Environments
• Static in Motion – Why ESD Is a Continuous Process
• Environment Changes Everything – Why ESD Behaviour Depends on Where It Operates

Why Choose SCH Services?

SCH Services supports customers with technically led coating selection, process development and production implementation for demanding electronics, industrial and specialist manufacturing environments.

• Practical coating and surface-engineering experience
• Support with material selection, testing and validation
• Application-led advice rather than generic product supply
• Experience across conformal coating, Parylene, advanced functional coatings and ProShieldESD static-control coatings

For support with static-control coating selection, surface behaviour, process validation or ProShieldESD applications, contact SCH Services to discuss your requirements.

This article is general technical guidance only. It does not replace hazardous-area assessment, explosive atmosphere classification, safety certification, ESD programme design, material compatibility testing or formal process validation. Final decisions must be verified against the applicable standards, site procedures, operating environment and qualification requirements.

Brush coating defects are often blamed on the brush, the operator, or contamination. In many cases, the real issue is that the coating viscosity has changed during use.

Solvent-based conformal coatings thicken as solvent evaporates. If the coating is held in an uncontrolled working jar, left open too long, or used beyond a defined working period, the viscosity can move outside the intended application range.

Controlled viscosity is therefore central to repeatable brush coating. It ensures the coating flows correctly from the brush, levels properly on the PCB, and reduces visible defects.

The coating is not always dirty

When operators see bubbles, lines or stringing in brush-applied coating, it is easy to assume the material has become contaminated.

Sometimes that can happen, but in many production environments the problem is not dirt. It is solvent loss and viscosity drift.

As solvent evaporates, the coating becomes thicker. Once the material moves outside the intended working viscosity, it no longer flows correctly from the brush or levels properly on the PCB.

For wider defect troubleshooting, see our guide to pinholes, bubbles and foam in conformal coating.

Key insight: Good brush coating depends on controlling viscosity at source, not asking operators to adjust coating at the bench.

Why controlled jars matter

A brush coating jar is not just a convenient container. It is part of a controlled viscosity system.

Using defined working jars reduces solvent evaporation, limits exposure time, and keeps coating within a usable viscosity range during application.

Working with small, controlled volumes also avoids repeatedly opening bulk material, helping maintain consistency across production.

How SCH controls brush coating viscosity

At SCH, viscosity is controlled centrally, not at the bench. Operators do not adjust or blend coatings during application.

Coating is issued in controlled working jars from viscosity-checked stock. Each jar is used for a defined time period, then replaced with a fresh, controlled jar.

Used coating is returned for controlled reblending under managed conditions. Viscosity is checked using appropriate methods, such as a Zahn cup, before being reissued as traceable stock.

Why operators should not adjust viscosity at the bench

Manual adjustment of coating viscosity at the bench introduces unnecessary variation. Different operators may add solvent differently, mix inconsistently, or judge coating behaviour by eye.

This variation affects coating thickness, flow, appearance and reliability, increasing the risk of defects and rework.

A stock of correctly blended, viscosity-controlled jars provides a faster, lower-risk process: use the jar, replace it at the defined time, and maintain consistent application.

Common defects linked to viscosity drift

• Bubbles forming during application
• Visible brush lines in the coating film
• Stringing between the brush and PCB
• Poor levelling after application
• Heavy local build-up or uneven coating appearance

These symptoms do not automatically mean the coating is contaminated. They often indicate that the working material has become too viscous for controlled brush application.

Where coating does not wet or flow properly on the board, viscosity should be considered alongside other causes such as de-wetting in conformal coating and surface preparation and cleanliness.

Related products and guides

For controlled manual coating work, SCH supplies practical application consumables used in real coating processes.

• Conformal coating jars for controlled brush coating and material handling
• Conformal coating brushes for PCB coating and touch-up
• Surface preparation and cleanliness for conformal coating
• Conformal coating thickness verification

These resources support repeatable brush coating by helping control the material, the application method and the inspection process.

Why Choose SCH Services?

SCH Services supports conformal coating processes with practical production experience, coating services, process consumables, equipment, training and technical support.

• Hands-on experience in real PCB coating production
• Practical support for brush coating, masking, inspection and process control
• Consumables selected for use in controlled coating workflows
• Technical guidance for reducing defects and improving repeatability

Contact SCH Services to discuss coating process support, consumables or manual coating control.

This article provides general technical guidance only. Final process settings, material handling methods and coating controls should be validated against the coating manufacturer’s datasheet, customer requirements and applicable production standards.

Most Parylene coating problems do not start in the chamber. They start earlier, in drawings and specifications that are too vague to control grade, thickness, adhesion route, masking intent or inspection expectations properly.

A note such as “apply Parylene coating” may appear acceptable at design stage, but it leaves too much open to interpretation once the work reaches purchasing, coating, inspection and quality. That creates avoidable variation before the process even begins.

This is why some Parylene programmes drift. The coating may be capable, but the specification is not strong enough to control it.

For detailed guidance, see our guide to specifying Parylene coating.

Key issue: if different teams can read the same coating note and reach different conclusions, the specification is not yet suitable for controlled production.

Where Parylene Specifications Usually Go Wrong

Most failures come from a small number of repeated mistakes rather than one major technical error.

• No defined grade – “Parylene coating” is written without specifying N, C, D or AF-4.
• Ambiguous naming – “Parylene F” is used without identifying the exact fluorinated grade.
• Unclear thickness – one number is given with no tolerance, target or measurement method.
• Missing masking intent – coated and uncoated areas are left open to interpretation.
• Assumed adhesion route – surface preparation or adhesion promotion is not defined.
• No acceptance criteria – inspection and release expectations are unclear.

Why This Becomes a Production Problem

Weak specifications do not just create technical uncertainty. They create misalignment between functions.

The supplier may quote based on one set of assumptions, the coater may process to another, and the quality team may inspect against something different again. That does not always lead to obvious coating failure, but it does lead to rework, delay and unnecessary disagreement.

In practice, many coating issues are specification-control issues rather than coating-process issues.

How to Fix It

A usable Parylene specification removes interpretation. It defines what is required clearly enough that engineering, coating and quality teams can work to the same intent.

At a minimum, a controlled specification should define the exact grade, the thickness requirement, any adhesion expectations, the coated and masked areas, and the acceptance or inspection route. If any of those are missing, the drawing is already carrying unnecessary risk.

For a practical step-by-step guide, see our guide to specifying Parylene coating.

Practical outcome: clear specifications reduce variation, improve repeatability and prevent disagreement between customer, supplier and quality teams.

Fix the Specification Before You Fight the Process

It is easy to treat coating issues as process problems because that is where they become visible. In many cases, the more effective fix is to strengthen the drawing before production begins.

If the grade is unclear, the thickness is vague, or the acceptance route is undefined, no amount of process discipline fully removes the underlying ambiguity. That is particularly important in higher-reliability work, where coating performance must be demonstrated, not assumed.

If the first question is still “which Parylene type should we use?”, start with our guide to choosing the right Parylene dimer.

Why Choose SCH Services?

Partner with SCH Services for a complete, integrated platform: Conformal Coating, Parylene & ProShieldESD Solutions plus equipment, materials, and training. Our team brings decades of hands-on expertise.

• ✈️ 25+ Years of Expertise – Trusted across aerospace, medical, defence, automotive, and electronics.
• 🛠️ End-to-End Support – From dimer selection to masking, inspection and process optimisation.
• 📈 Scalable Capacity – From prototypes to high-volume production.
• 🌍 Global Reach – Responsive support across Europe, North America, and Asia.
• ✅ Proven Reliability – Consistent quality and strong customer satisfaction.

📞 Call: +44 (0)1226 249019
✉ Email: sales@schservices.com
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Note: This article provides general technical guidance only. Final design, safety, and compliance decisions must be verified by the product manufacturer and validated against the applicable standards.