Need Reliable, Splashproof Devices? If You’re Using Mechanical Seals, You’d Better Look Elsewhere.

Mallory McGuinness | March 18, 2020

It doesn’t matter which type of mechanical seal you use: gaskets, glues, and o-rings can easily become damaged or dislodged. Even if they don’t, they’ll wear out over time. And when a busted mechanical seal meets water, it doesn’t bode well for your products.  

Ionized water can annihilate an electronic circuit design with a single short, and corrosion is a silent, misunderstood killer. This is because when water hits an electronic product, it may continue to work temporarily if it does not immediately short out. This can leave customers confused when the product stops working days later as corrosion has eaten away at their device (for more information see our blog on corrosion). All told, the direct and indirect annual costs of corrosion have tallied up to $552 billion in the US alone1. 

mechanical seals failing to protect products

All told, the direct and indirect annual costs of corrosion have tallied up to $552 billion in the US alone.

Some of these costs come in the form of product returns, which happen when customers expect reliable moisture protection and wind up with a defective device destroyed by corrosion.  

If you’re a manufacturer, returned products alone can sap anywhere from 8-15% of your company’s top line2. (Bear in mind that this figure doesn’t include potential sales that can be lost as a result of brand reputation damage). This is neither a happy statistic for OEMs, nor customers who expect reliable splashproof products.

You might be wondering why mechanical seals are so inefficient when it comes to protecting electronic devices from liquid exposure and corrosion. Here are just some of the reasons why trying to protect components with mechanical seals will cause products to break, resulting in returns and damaged brand reputation after liquid contact. 

What Causes Water-Repellant Mechanical Seals to Fail?

  • A simple drop to a device. 
  • Thermal shock. 
  • Temperature ranges too hot or cold for the seal installation.  
  • Degrading chemical reactions upon exposure to common liquids like oils, suntan lotion, or water with corrosive agents.  
  • The mechanical seal covers must be closed at all times to prevent liquid ingress, an unrealistic expectation that is rarely met.  
  • The test of time, after simple wear and tear.


Maybe it’s time to consider dependable protection alternatives – “hydrophobic” conformal coatings that will cost less to apply than product returns due to broken mechanical seals. 


Conformal Coatings Protect the Printed Circuit Board (PCB)


Across industries, manufacturers are turning to the conformal coating solution to prevent water damage. With conformal coating, polymeric films are applied to board components, forming a long term seal to protect the board. 

Done properly, conformal coatings will offer enhanced protection against harsh environments, working to extend product lifespan and preventing corrosion. They can also increase dielectric strength between conductors, which allows you to design a smaller, lighter PCB. 

Conformal Coatings Can:

  • Stop liquids from contacting energized circuits.  
  • Protect components from vapor damage resulting from moisture, salts, and more.  
  • Mitigate tin whiskers. 

Traditional Types of Coating:

  • Epoxies 
  • Urethanes 
  • Acrylics 
  • Silicones 

Typical Conformal Coating Application Methods:

  • Spraying the film onto the PCB. 
  • Applying the coating with a brush. 
  • Dipping the PCB in a tank of conformal coating.  


While conformal coatings offer reliable splashproof protection and allow for a smaller, lighter design, the liquid application methods we just mentioned have a number of drawbacks.  

First, liquid application entails manual work, and manual work means that opportunities for mistakes can occur. The results of these mistakes, which are listed below, can leave an electronic vulnerable to liquid damage.

Problems with Traditional Conformal Coatings and Liquid Application:

  • Non-uniformity
  • Dewetting 
  • Subpar coverage 
  • Fisheyes 
  • Bubbles & voids 
  • Cracks & ripples 
  • Orange peel 
  • Delamination

Second, traditional conformal coatings require heat curing so that they can harden, adding even more time to your endeavor. And as the coatings dry during the curing process, potentially harmful solvents can be released. 

Solution: Use Plasma Polymerized Nano Coatings to Protect Your Product from Punishing Operating Environments 

Forward-looking thinfilm coating vendors are using plasma polymerization, a superior coating process. These vendors use vacuum deposition machines for application. Coatings in the plasma phase deposit evenly on the substrate, settling into every crevice. Deposition can be accomplished with minimal handling or sample preparation, and labor and time-intensive masking and demasking isn’t required.  

a diagram explaining plasma polymerization

The process is simple, repeatable, effective, and user friendly.  

  • The plasma based nano coatings deposit as thin, pinhole-free films in just one step.  
  • Coatings deposit uniformly on all surfaces exposed to active plasma.  
  • Coating around corners and edges of components is easy with plasma based nano coatings, while traditional liquid coating methods will run off of these sharp edges.  
  • Plasma polymerized thin films form strong bonds with substrates that have been coated. 
  • Plasma based nano coatings have a thickness ranging from a few 10’s of nanometers to several micrometers, allowing for a more compact device.  
  • No hazardous waste or conflict metals are involved.  
  • The coatings are multilayer films, with the top layer being “hydrophobic” – the water simply rolls off of the surface.  
  • With plasma based nano coatings, It is easy to rework assemblies.   

Plasma Based Nano Coatings Enhance Reliability of PCBs, Providing Superior Protection From:

  • High Temperatures 
  •  Salt Spray 
  •  Humidity 
  •  Condensation 
  •  Water immersion 
  •  Noxious/Corrosive Gases 
  •  Solvent Splash/Spill/Immersion

If you’re a manufacturer, returned products alone can sap anywhere from 8-15% of your company’s top line.

Mechanical Seals and Moisture Protection Don’t Mix. 

In a series of rigorous tests performed by HZO, an electronic device that carried an IPX7 water-resistance rating protected by mechanical seals was subjected to conditions found in daily life: temperature fluctuations, drops and bends, and humidity. After being exposed to these circumstances, the device did not function.  

But the electronic coated by us was up and running after the same stress tests. That’s because HZO offers reliable splashproof protection with plasma polymerized nano coatings that nobody else in our industry can deliver.  

Our proprietary equipment with the largest coating chambers in the industry allows for unparalleled scalability. We’re ready to get to work when you are, and we walk with you every step of the way through the splash proofing process. 

Other Features Unique to HZO:

  • Our many intellectual property assets defend you from property risk. 
  • A high process throughputthroughput process optimized for manufacturing and cost simplifies your production. 
  • Maximized product throughput reduces cost. 

If you are tired of dealing with returns due to mechanical seal failure and liquid exposure, we invite you to get in touch with us. We can meet any IP code (ingress protection) easily, quickly, and reliably. If you’re struggling to find a solution that will end returns due to liquid damage, you’ve got nothing to lose but money and reputation. 

Looking to build a splashproof deviceDrop us a line and tell us how we can help. 

1Koc, G.H.; Brongers, M.P.H.; Thompson, N.G.; Virmani, Y.P.; Payer, J.H. Corrosion Costs and Preventive Strategies in the United States; NACE International: McLean, VA, USA, 2002

2Aberdeen Group Inc., Revisiting Reverse Logistics in the Customer-Centric Service Chain (2006).

Mallory McGuinness

Mallory is an electronics protection evangelist who writes content for HZO. In her free time she is reading non-fiction, and hanging out with her beta fish, King Awesome.
an electronics protection evangelist

Ryan Moore

Ryan is a 9-year veteran to the world of protecting electronics from harsh environments and a lover of all things technology.

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