Why the UK Heatwave Is Not Stopping Our Conformal Coating Process
Over the last few weeks we have received several customer questions about the UK heatwave and whether unusually warm conditions affect conformal coating processes.
It is a sensible question. Many manufacturing processes become difficult to control when temperatures rise, materials warm up and factory conditions begin to drift away from normal operating ranges.
At SCH Services, however, we have continued coating throughout the recent hot weather. During some of the warmest periods our coating environment has been operating at approximately 29°C and 55% relative humidity while continuing to process customer products successfully.
The interesting part is not the temperature itself.
The interesting part is that temperature is often not the factor experienced coating engineers worry about most.
In many cases, humidity, process control and understanding material behaviour are far more important than a headline temperature reading.
Customers Often Focus on Temperature First
When a heatwave arrives, temperature becomes the obvious concern.
People naturally assume that coatings will become unusable, defects will increase and production quality will suffer simply because the thermometer is showing a higher number than normal.
Temperature certainly matters.
It influences viscosity, solvent evaporation, flow characteristics, spray behaviour and cure rates. Every coating chemistry responds differently as temperatures rise.
However, temperature on its own rarely tells the full story.
A controlled process running at 29°C can often be more stable than an uncontrolled process running at 22°C.
The question is not simply:
“How hot is it?”
The more useful question is:
“Do we understand how our process behaves under these conditions?”
Humidity Is Often the Bigger Risk
One of the most common misconceptions in coating operations is that temperature is the primary environmental threat.
In reality, humidity often creates more production problems.
Depending on the coating chemistry being used, elevated humidity can contribute to:
- Blooming and whitening defects
- Surface haze
- Poor appearance
- Adhesion variation
- Moisture-related contamination issues
- Inconsistent curing behaviour
Many coating engineers therefore spend as much time monitoring relative humidity as they do temperature.
During the recent heatwave, our operating conditions remained around 55% RH. While warm, these conditions remained manageable because both temperature and humidity were understood, monitored and controlled.
The lesson is simple.
Environmental numbers by themselves are not the problem. Uncontrolled environmental conditions are.
Process Control Matters More Than Weather Headlines
Manufacturing reality is rarely as simple as a single temperature limit.
Experienced coating operations look at the entire process:
- Material storage conditions
- Coating viscosity
- Application method
- Humidity trends
- Air movement
- Drying behaviour
- Cure conditions
- Operator observations
This is why two companies can experience completely different results while operating at the same ambient temperature.
One organisation may encounter defects because environmental changes are unmanaged.
Another may continue processing normally because the process has been designed to accommodate realistic manufacturing conditions.
The weather has changed.
The engineering principles have not.
The Real Engineering Question
The recent UK heatwave provides a useful reminder that process knowledge matters more than assumptions.
Instead of asking whether a coating process can operate at 29°C, the better question is:
“What happens to this specific coating chemistry when temperature and humidity change?”
That question leads to useful engineering decisions.
The temperature number on its own rarely does.
At SCH Services, our recent experience has simply reinforced a lesson that coating engineers learn repeatedly over time:
Temperature matters. Humidity often matters more. Process control matters most.
Continue Learning
This insight introduces a broader engineering topic that affects coating quality, process stability and defect prevention.
For a deeper technical understanding, explore:
- Temperature Effects on Conformal Coating Processes
- Humidity Effects on Conformal Coating Processes
- Masking Tape Lifts During Hot Weather
Understanding how environmental conditions influence coating behaviour helps prevent defects long before they appear on production hardware.
Why Choose SCH Services
SCH Services provides conformal coating, Parylene coating, process development, training and consultancy support for electronics manufacturers across the UK and Europe.
Our guidance is based on real production experience, practical process control and day-to-day operation of coating systems rather than theoretical specifications alone.
Where environmental conditions, coating performance or process stability are creating concerns, we can help evaluate the issue and identify practical solutions.
Disclaimer: This article provides general engineering guidance based on practical conformal coating experience. Environmental suitability, process limits and coating performance should always be validated against the specific coating chemistry, equipment and production conditions being used.
