Silicone, EPDM & Vinyl Masking Caps Explained

There are many types of masking caps, but materials will play a large role in the success of finishing your application. But which masking cap materials should you consider? That depends on the masking process, your budget and what you need the cap to do exactly. This guide focuses on high-temperature masking cap materials, covering:

• Silicone Masking Caps
• Vinyl Masking Caps
• EPDM Masking Caps
• What are their differences?

Silicone masking caps typically come in different colours for several practical reasons:

1. Identification: Different colours help identify and distinguish between masking caps of different sizes, shapes, or properties. This aids in organisation and inventory management, especially when a wide range of masking-cap options are used.
2. Colour coding: Some industries or applications may use colour-coded systems to signify specific characteristics or functions of masking caps. For example, certain colours may indicate temperature resistance, chemical compatibility, or intended use, allowing for easy identification and selection.
3. Aesthetics: You can match masking caps with the colour scheme of your equipment or corporate branding. 

But it’s the characteristics of silicone rubber that makes it so desirable as a masking cap.

Advantages & Benefits

Choose silicone masking caps when these characteristics matter:

• Temperature resilience: Silicone maintains its integrity even in high-temperature environments, making it ideal for applications involving heat curing or elevated temperatures. Our range of silicone masking caps and plugs stand up to 316°C.
• Chemical endurance: Resistant to various chemicals, oils, and solvents, silicone ensures the longevity and effectiveness of masking caps, even in harsh chemical settings.
• Flexibility: Exhibits remarkable flexibility and stretchability, enabling masking caps to seamlessly conform to diverse shapes and sizes of components, ensuring precise masking.
• Durability: Can withstand repeated use, giving you a cost-effective masking solution. 
• User-Friendly: Easy to apply and remove, streamlining masking and unmasking processes, and bolstering overall operational efficiency.

View our range of silicone masking caps

Get to know this material better. Our experts explain the mechanical and physical properties, plus more, in our guide, What is Silicone Rubber?
 

Vinyl and PVC (polyvinyl chloride) are often used interchangeably, but they are not exactly the same. PVC is a type of vinyl, specifically a polymer of vinyl chloride. Vinyl, on the other hand, is a broader term that encompasses various polymers containing the vinyl group (-CH=CH2), including PVC.

In essence, PVC is a specific type of vinyl polymer. However, vinyl can also refer to other polymers such as polyvinyl acetate (PVA) or polyvinylidene chloride (PVDC), which are different from PVC.

So, while PVC is a type of vinyl, vinyl is a more general term that can include PVC as well as other vinyl-based polymers.

Advantages & Benefits

PVC and vinyl masking caps are good choices when you need these characteristics. A great example is our vinyl end caps. 

• Flexibility: Vinyl's inherent flexibility allows caps to conform to diverse component shapes, ensuring a snug fit for effective protection during masking processes.
• Temperature resilience: Some PVC masking caps are formulated to withstand temperatures of up to 218°C.
• Chemical resistance: Withstanding a range of chemicals including solvents, oils, and acids, vinyl caps are suitable for use in different industrial environments.
• Durability: These caps boast robustness, maintaining integrity even after prolonged use and exposure to harsh conditions, ensuring reliable, long-lasting protection.
• Easy application and removal: Simple to install and remove, they streamline production processes, whether applied manually or via automated equipment, saving time and effort.

You can get a deeper understanding of this material in our guide, What is PVC (Polyvinyl Chloride)?

View our PVC High-Temperature Masking Caps

Like silicone, EPDM (Ethylene Propylene Diene Monomer) is a synthetic rubber. The two materials share many similarities as masking caps, such as the ability to be used multiple times. EPDM typically costs around 30% less than silicone, which partly comes down to raw-material availability and lower production costs. 

Advantages & Benefits

EPDM caps have a lot going for them:

• Chemical resistance: They excel in withstanding a wide range of chemicals, including acids, alkalis, and solvents, ensuring suitability for environments with aggressive chemical exposure.
• Weather resistance: EPDM caps are highly resistant to weathering, UV radiation, and ozone, making them ideal for outdoor applications subjected to harsh environmental conditions.
• Temperature resistance: EPDM caps maintain their sealing properties across a broad temperature range, from low to high temperatures, ensuring reliable performance in diverse operating environments. Our own range of EPDM caps stand up to 218°C.
• Flexibility: With their elastic properties, EPDM caps easily conform to various shapes and sizes, ensuring a snug fit over components and effective protection against leaks.
• Durability: They exhibit remarkable durability, resisting tearing, abrasion, and punctures, which contributes to their long-term reliability in protecting components.
• Easy installation and removal: Designed for user convenience, EPDM caps can be effortlessly installed and removed without leaving behind residue or causing damage to the surface.

You can learn more about this material in our guide, What is EPDM Rubber?

View our EPDM High-Temperature Masking Caps

What are their differences?

With so many similarities, the differences between EPDM, silicone and vinyl masking caps can seem subtle. 

Silicone Masking Caps:

• Excel in temperature resistance and flexibility, making them suitable for higher-temperature masking applications.
• Maintain their properties over a wide temperature range, from -50°C to 200°C or higher, without degrading or losing elasticity.
• Good chemical resistance and commonly used where flexibility, heat resistance, and durability are critical, such as in the automotive, aerospace, and electronics industries.  

Vinyl Masking Caps:

• Cost-effective and offer moderate resistance to chemicals and environmental factors.
• Rigid and less flexible compared to EPDM and silicone, making them suitable for applications where a snug fit is required, such as masking threaded studs or bolts.
• Commonly used in less demanding applications where cost is a primary consideration, such as plating, painting, or electrocoating processes.

EPDM Masking Caps:

• Provide superior flexibility and elasticity, allowing them to conform to various shapes and sizes of components.
• Commonly used in applications where exposure to harsh environmental conditions or chemicals is a concern, such as automotive painting, powder coating, and anodising processes.

Our experts have written an extremely helpful guide that can help you choose your masking cap materials: Masking Materials Selection Guide.

Download free CADs and try before you buy

Free CADs are available for most solutions, which you can download. You can also request free samples (some exclusions apply) to ensure the product you’ve chosen is exactly what you need. 

If you’re not quite sure which solution will work best for your application, our experts are always happy to advise you.

Request your samples or download free CADs now.

Questions?

Email us at sales@essentracomponents.co.uk or speak to one of our experts for further information on the ideal solution for your application 0345 528 0474.