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Five Top Tips For Choosing Caps or Plugs

Choosing the right cap or plug to protect your application can be challenging. Our Top Tips Guide will take you through the key areas to consider, ensuring you have covered all bases before you make your purchase. So whether you are protecting your product in transit or masking holes in the painting process, caps and plugs are essential to ensuring your parts remain safe and functional.

Caps and Plugs - Essentra


Considering your environment is key when looking to protect your parts or products and can dictate what cap or plug is used for your project. There are varying environmental factors such as:

Sunlight – is there a need for UV resistance?

High levels of moisture and humidity.

Presence of corrosive substances.

Electricity – is there a necessity to conduct or dissipate electricity?

Temperature – is your application operating in hot or cold conditions?

Pressure – are there Pounds per Square Inch (PSI) considerations?


We know that you are producing products for various applications in your business, so understanding the variables your application brings is key. Firstly, think about whether you need to protect or mask.
Protection – consider what part requires protecting and how the cap or plug needs to perform. For example, if you are protecting a profile with an interior thread you may select a threaded plug or if the application requires shielding against entry or escape of liquids, then an o-ring could be applied.

Masking – consider the surface area and the complexities of the masking process, which can include painting, blasting or high-temperature drying. For example, if you are masking a number of holes in a high-temperature environment you may select a high-temperature flangeless silicone plug that includes tapered rings to allow a variety of hole diameters to be masked.


Choosing the right material for your environment plays an important role in selecting your cap or plug. One of the most critical factors is heat. This can immediately indicate whether you need a standard Low-Density Polyethylene (LDPE) material or if you need something more flexible or heat tolerant, such as PVC or Silicone. A silicone cap will be able to operate safely at +250°C, whereas LDPE can only operate safely up to 65°C.¹

Another consideration is whether the cap or plug is required to withstand a high impact environment or provide shock absorption. Without considering your material, you can waste money and delay your projects.


Understanding your production process allows you to consider how caps and plugs can be applied. These can vary from manual to tool-based processes.

A push fit cap or flanged plug can be applied to fit multiple profiles. This allows for fast hand application, which is essential if you are looking to save time.

For tool-based processes, a cross head, custom cap or plug can be used.

Choosing the right caps or plugs for your production process


The removal process can be conducted internally in your production environment or in the hands of your customers. In your production environment, applications that require protection of threads or profiles must be carefully removed and may take time. To save time in your production schedule, an ezeplug can be used. Some caps and plugs can be reused after removal, giving you cost savings.

For your customers, ease of removal is essential. Giving them a positive experience is important, so the addition of a pull tab or flange on your cap or plug will inject speed and efficiency into the removal process.

Did you know? Tailoring protection around your production methods can help to reduce wasted time and increase efficiency. Manufacturers need to be able to monitor and optimise their processes to ensure they are as efficient as possible.²

For more advice about caps and plugs, please call us on 0845 758 5070 or email sales@essentracomponents.co.uk


¹British Plastics Federation (2015)

²PWC (2015) - Achieving excellence in production and supply