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The Ultimate Guide to Caps and Plugs

clock 22 minutes | 04 Feb 2020

The Ultimate Guide to Caps and Plugs

General Protection

Not every general protection product is suited for every application. Materials play a critical role. For instance, you wouldn’t use a stud bolt protection cap as a high-temperature masking solution. For starters, they’re made of Low Density Polyethylene, which can’t stand up to high temperatures, but provides excellent performance for a basic application, such as for storage and transportation.

To help you select the right caps and plugs for your application, we’ve put together this guide. We strongly recommend that you try before you buy – request free samples to ensure that the Essentra product selected matches your requirements.

What do you want to know?

Types of caps and plugs

Before you can understand the materials, you need to know the types of caps and plugs available. Caps and plugs are designed for every use in a variety of materials. You can even have them custom made. Decide your priorities and then you can choose the most suitable caps and plugs.

  • Manufacturing – To keep production moving efficiently, always consider the time it takes to apply and remove caps and plugs without damaging threads or profiles; an easy pull plug or tear tab caps work well, for example. If you can adapt your protection to your production methods, you’ll work far more productively.
  • Masking – Areas you especially need to protect include electrical contact points, threaded holes or studs and welding areas. Materials react differently to processes, so before you actually start masking, request a free sample of the masking product you’d like to use and test it. Keep in mind that caps and plugs aren’t your only option. Masking tape might be best for your needs.
  • Storage and transportation – Components are especially vulnerable to damage and contamination during transportation and storage, which is why caps and plugs are often used to protect critical profiles in those situations. Tapered round plugs with flange, for example, are often used for storage and transportation, providing protection against dirt, debris, moisture and corrosion.
  • End use – Caps and plugs are often used to finish off a product, such as furniture or panels. Decorative hex bolt caps or a round ferrule are good examples, while also providing protection.
Type Purpose & Materials
Tapered caps and plugs Snug fit
Tapered caps and plugs have just that: a tapered design, which covers several diameters. They provide a tight fit, protecting your application from contamination, damage and corrosion during storage and shipment.
Push fit caps Protection for profiles
Protect internal and external profiles during assembly and transit. Push fit caps are ideal for this purpose. They’re available in different styles and materials suited to your application.
Vinyl caps Flexibility is key
Vinyl caps provide a level of flexibility that allow for stretching without tearing or splitting. The result is a snug fit that’s just as easy to remove.
Threaded cap and plug Protect threads
Threaded caps and plugs are most often used as protection on hydraulic hose fittings. They provide a quick fit to threaded components and can serve as metric threaded caps, BSP pipe plugs – they also fit UNF thread sizes.
Quick fit and/or removal plugs When every second counts
Quick fit plugs have a short thread to allow for a fast fit. Their knurled head provides an easy grip to speed up the installation and removal process even more.


Specialty caps and plugs

Type Purpose & Materials
Masking protection Caps and plugs designed for masking provide protection from surface treatment in applications which require different levels of temperature and chemical resistance. These are available in different materials and offer varying temperature tolerances. The one you choose will depend on the masking application you’re using.
Protection for pipes and flanges From Flange Protector Retainer Plugs to Pipe Caps, you can keep pipes and flanges safe and sound, free from damage and contamination. These caps and plugs offer firm and secure protection in different styles.
Protection for pipes and flanges Hydraulics has its own safety demands and standards, which is why specialist caps and plugs are essential for protection. The range of solutions available is vast, from banjo union caps to quick release plugs.

Click on the image below for the full buyer's guide:

Caps and Plugs Buyer's Guide

Materials overview

How do you know which material you should use for your application? To give you a head start, here’s a quick look at the characteristics of materials for caps and plugs:

Blue and orange plastic pellets

Plastics

Material

Characteristics

Low-Density Polyethylene (LDPE)

Flexible, economical, good chemical resistance

High-density Polyethylene (HDPE)

Excellent resistance to most chemicals, but poor resistance to oil and grease

Nylon

Tough material with good thermal and chemical resistance

Ethylene Vinyl Acetate (EVA)

Good chemical and stress-crack resistance; works well for electrical applications

Polypropylene (PP)

Good chemical and heat resistance

Polyvinyl Chloride (PVC)

Flexible, withstands high temperatures

Copolyester

Blend of different polyesters; high clarity and transparency with excellent chemical resistance

Thermoplastic Elastomers (TPE)

Soft, resistant to UV rays. Some manufacturers class TPE as a rubber


Rubber

Material

Characteristics

Ethylene Propylene Diene Monomer (EPDM)

Highly flexible; similar to silicone but has lower temperature resistance

Silicone

Resistant to high and low temperatures


Other materials

Material

Characteristics

Vinyl

Withstands high temperatures. Durable and abrasion and moisture resistant

Thermoplastic Rubber (TPR)

High resistance to chemicals; combines the properties of rubber with the mouding capabilities of thermoplastics

Paper(Crepe)

High degree of flexibility

PVC

A type of vinyl. Popular in the construction industry for its durability and cost.

Click on the image below for the full design engineer's guide:

Caps & Plugs Design Engineer's Guide

When materials are similar

This often makes choosing a material for your caps and plugs difficult. Here are the differences in the materials that many find confusing. You can find a material’s specific properties here.

LDPE vs. HDPE

They’re both made of polyethylene (PE), one having low and the other, high density, In fact, LDPE has a density in the range between 0.910 and 0.925 gm/cm3. HDPE, within the range of 0.941 to 0.965 gm/cm3.

As to characteristics, LPDE has a high ductile nature and mediocre tensile strength. HPDE has high tensile strength. Both LDPE and HDPE are flexible. LDPE stretches and conforms better to surfaces than HDPE, which is tougher and more rigid. Here’s a more in-depth look at LDPE vs. HDPE.

HDPE vs Polypropylene

Polypropylene is a thermoplast polymer. Like HDPE, it’s rugged and can resist chemical solvents and acids. However, they differ in density, with polypropylene between 0.895 and 0.92 g/cm², making it more flexible than HDPE. Another difference is that polypropylene has poor UV resistance.

EPDM vs Silicone

Both are rubbers. EPDM is popular in the automotive and construction industries. Your car’s door and window seals are most likely EPDM, for example. Silicone has a longer life than EPDM, but the main difference in these two materials comes down to their ability to withstand extreme temperatures. Silicone is the runaway winner. Here’s a closer look at EDPM vs. Silicone.

TPE vs TPR

Both materials belong to the family of thermoplastic elastomers. TPR has qualities that combine the properties of rubber with the moulding capabilities of thermoplastics. Yet these two materials are so much alike in their characteristics. Both have high-flexural fatigue resistance, high-impact strength – even their temperature ranges are the same. The difference comes down to their base materials.

TPE is modified from Styrene Ethylene Butylene Styrene Block Copolymer (SEBS) and has a lower density than TPR. TPR is often modified from styrene-butadiene-styrene block copolymer (SBS). The result is that TPE is essentially a softer version of TPR. Here’s a more in-depth look at TPE vs TPR.

Industries: which solutions?

Not every material works for every cap and plug, of course. Here’s a glance at examples of what material works best in specific applications.

Equipment Manufacturing

Blanking plugs, for example, are often used to finish off panel holes on a piece of equipment, giving it a nice, clean finish and providing safety against sharp edges. They’re available in different materials, but which should you choose and why?

Nylon, PVC or copolyester?

Your choice will depend on the equipment being manufactured. If you’re dealing with irregular shapes, or wires and cables that will need to be accessed, you want a flexible material for your blanking plug which can easily be removed when needed. This is why the automotive industry uses flexible blanking plugs. If it’s a straightforward job, and the blanking holes are merely there for appearance, then nylon will fulfil your need. It’s a hard, long-lasting material. If you want a clear plug, opt for copolyester.

Blanking Plug

Blanking Plug

Choose nylon or copolyester for rigidity and durability

Body Plugs

Body Plugs

These push in plugs for panels come in silicone or TPR for flexibility, covering multiple diameters

Masking

For masking to be successful, your material selection is critical. It’s got to behave as required during wet painting, powder coating, e-coating, anodizing, plating, blasting and drying. Your material has to stand up to the operating temperature that your application requires. Before you actually start masking, request free samples of the masking product you’d like to use and test it.

Masking tape can also give you a very economical, easy-to-use solution. For instance, if you’re masking sheet metal, tape is easy to apply and remove.

Which material for your masking application?

Masking solutions to consider, depending on the process you’re using:

Process Feature Powder coating E-coating Anodizing Plating Wet Painting Blasting Max Temp
Silicone Premium; reusable
+250°C
+482°F
Polyimide Tape Premium; excellent solvent
+260°C
+500°F
Silicone Tape Self bonding; perfect for irregular shapes
+204°C
+399°F
Glass Cloth Tape Durable; for blasting or thick coatings
+180°C
+356°F
EPDM Costs around 30% less than silicone
+150°C
+302°F
High-Temp Vinyl Low cost; not reusable
+170°C
+338°F
TPR / TPE Lightweight
+95°C
+203°F
Paper Low cost; recyclable
+120°C
+248°F
Polyester No shrinkage
+150°C
+302°F
High-Temp Crepe Special high-temp formula
+204°C
+399°F

We do not assume any liability for the materials, specifications or information provided. For complete temperature and other physical properties of our products’ material, please refer to the actual product material technical data sheet, available upon request.

Masking Pull Plugs

Masking Pull Plugs

Available in Silicone & TPR

Masking Flangeless Plugs

Masking Flangeless Plugs

Available in EPDM & TPR

Easy-Pull Masking Caps

Easy-Pull Masking Caps

High temperature rubber cap in silicone & EPDM; Also, PVC

Coloured Masking Tape – Discs

Coloured Masking Tape – Discs

Available in polyimide

Masking Washer Caps

Masking Washer Caps

Available in silicone & EPDM

Vehicles

The concern here is with precision. Key vehicle parts to protect are:

  • Diesel/petrol pumps
  • Engines
  • Specialist vehicle fittings
  • Powertrains
  • Brake systems

What materials will help you protect fuel lines with integrity? The aim should be to prevent contamination while protecting threads from damage during shipment and masking.

LDPE is usually used to protect products during transit and storage. It’s relatively rigid and offers a secure fit for maximum protection, with good impact resistance. Its protection parts are sometimes threaded so that it can be screwed onto threaded studs and removed without too much fuss. An example of an unthreaded LPDE solution is a grease nipple cap, which protects grease nipples from dirt ingress when not engaged with its mating part.

Vinyl offers a snug fit, even for small dimensions or irregular shapes. Despite its softness, vinyl resists tearing, cracking, splitting and shredding and is easy to remove. Vinyl caps provide an airtight seal while also insulating and cushioning. If your first priority is shock resistance, vinyl offers excellent protection during transport and handling.

Banjo Bolt Cap

Banjo Bolt Cap

Bolt caps made of LDPE for assembly, storage and transportation

Side Pull Plugs

Side Pull Plugs

Pull tab feature designed for fast, easy removal; Available in LPDE and TPR

Quick-Fit Connector Plugs

Quick-Fit Connector Plugs

Protects fuel systems; ring tab allows for easy removal; available in LDPE

Threaded Protection Caps - BSP/Gas Threads

Threaded Protection Caps - BSP/Gas Threads

Protects threaded components from dust, moisture and damage; LPDE

Hoses and Hydraulics

You’ll need specialist protection to ensure the safe operation of any fluid hydraulic component. A cap or a plug will protect the coupling whilst minimising the impact of fluid spills and maintaining hose integrity. Common materials for caps and plugs for this application include:

  • LDPE
  • HDPE
  • TPE
  • PVC

LDPE material is both cost effective and efficient. For these applications, caps are flexible and easy to fit and do an excellent job of sealing hydraulic applications from damage during transit, heat, dirt, moisture and corrosion. HDPE is more rigid and resists solvents, which can be an important factor in hydraulics. TPE’s broad temperature range means it can withstand the outdoors well. Its ability to be soft enables it to shape to fit and retain its position.

Quick Release Plugs

Quick Release Plugs

Made of TPE for excellent flexural fatigue resistance

Threaded Protection Plugs

Threaded Protection Plugs

LDPE protects against contamination and PP provides good chemical resistance

O-ring Seal Caps

O-ring Seal Caps

LDPE protects O-ring face seal connectors

Threaded sealing caps

Threaded sealing caps

HDPE caps are resistant to solvents and reduce potential shearing

Driveshaft Protection Caps

Driveshaft Protection Caps

Available in flexible PVC and LDPE to protect driveshaft and surrounding bearings

Pipe Protection

Materials aren’t quite as varied when it comes to industrial pipe protection, but you still have some decisions to make: LPDE, PE and vinyl.

You have to check these materials off against the three areas that matter most to your pipes, and prioritise them in order of importance to you:

  • Durability against impact
  • Ease of use
  • Quality of your materials

LDPE is a low-cost, weatherproof material, and resists chemicals. Durable yet lightweight, these caps are easy to remove and 100% recyclable. Vinyl is attractive as pipe protection due to its flexibility. It stretches over threads to provide a tight seal that keeps out contaminants. PE is a good choice too. It’s a cost-effective material while protecting from damage during storage and transportation.

Flexible Pipe Caps

Flexible Pipe Caps

Flexible PE allows for easier fitting

Ribbed Pipe-End Plugs

Ribbed Pipe-End Plugs

LDPE flexible ribs of different diameters provide friction fit

Face Protectors - Barreled

Face Protectors - Barreled

Durable PE protects flange face against dirt, moisture, paint, sand and short blasting; tapered section creates strong adhesion to the collar of the pipe; fasteners not required

material properties

Materials Properties

Below is a list of materials, and their properties, commonly associated with caps and plugs. Note, these are not the properties of the caps and plugs themselves, but of the material. Materials can be formulated to enhance or take on specific qualities. Still, it’s a good starting point for understanding certain materials.

Plastics

Low Density Polyethylene (LDPE)

The most popular choice for caps and plugs for using as protection during transport, and not just because of its low cost relative to other materials. LDPE is rigid, but compared to Nylon or HDPE, it’s soft. It also has high impact strength and a reputation as a cross between elastomers and thermoplastics. LDPE can withstand the cold, specifically temperatures down to 0˚C before it becomes brittle. When placed in high temperatures, it quickly becomes soft.

Generally, LDPE offers:

Tensile Strength

0.20 - 0.40 N/mm²

Notched Impact Strength

no break Kj/m²

Thermal Coefficient of Expansion

100- 220 x 10-6

Max Cont Use Temp

65˚C / 149˚F

Density

0.917 - 0.930 g/cm3


Resistance to chemicals:

Dilute Acid

Excellent

Dilute Alkalis

Excellent

Oils and Greases

Moderate (variable)

Aliphatic Hydrocarbons

Poor

Aromatic Hydrocarbons

Poor

Halogenated Hydrocarbons

Poor

Alcohols

Excellent

Hexagonal cap

Hexagonal cap

LDPE caps also protect round components on hydraulic applications

NPT Thread Plug

NPT Thread Plug

Designed for use with BSP/NPT tapered threaded fittings

Snap Fit Plug

Snap Fit Plug

Centre tab enables tight grip for easy application and removal

High density Polyethylene (HDPE)

HDPE is a stiff, strong, high-density material and similar to LDPE in opacity and impact resistance. With good chemical resistance and low permeability to gases and moisture, it’s a good – although not the most common – choice for protecting NPT thread ports from dirt and other contaminants.


Generally, HDPE material has:

Tensile Strength

0.20 - 0.40 N/mm²

Notched Impact Strength

no break Kj/m²

Thermal Coefficient of Expansion

100- 220 x 10-6

Max Cont Use Temp

65˚C / 149˚F

Density

0.944 - 0.965 g/cm3


Resistance to chemicals:

Dilute Acid

Excellent

Dilute Alkalis

Excellent

Oils and Greases

Moderate (variable)

Aliphatic Hydrocarbons

Poor

Aromatic Hydrocarbons

Poor

Halogenated Hydrocarbons

Poor

Alcohols

Excellent

Threaded Protection Plugs - NPT Threads

Threaded Protection Plugs - NPT Threads

Easy-to-grip head design; also available in nylon

Threaded Sealing Caps - UNF Threads

Threaded Sealing Caps - UNF Threads

Protection while limiting fluid leakage

Threaded O-ring Plug - Metric Threads

Threaded O-ring Plug - Metric Threads

Water-tight seal to protect against leakage; also available in nylon

Yellow caps

Nylon

Nylon is a tough material with good thermal and chemical resistance. It’s incredibly strong and can be used in place of low-strength metals. It’s a popular material, used to make everything from fasteners to cable ties. Nylon 6.6, a variant, is stronger and absorbs less moisture than Nylon. It’s the ideal material when high level of torque is required.

Generally, nylon material has:

Tensile Strength

90 - 185 N/mm²

Notched Impact Strength

5.0 - 13 Kj/m²

Thermal Coefficient of Expansion

90 - 20/70 x 10-6

Max Cont Use Temp

130˚C / 266˚F

Density

1.13 - 1.35/1.41 g/cm3


Resistance to chemicals:

Dilute Acid

Poor

Dilute Alkalis

Moderate

Oils and Greases

Excellent

Aliphatic Hydrocarbons

Excellent

Aromatic Hydrocarbons

Excellent

Halogenated Hydrocarbons

Good (Variable)

Threaded Protection Plugs - Wide Flange

Threaded Protection Plugs - Wide Flange

Absorbs paint and keeps flaking at a minimum avoiding contamination upon removal

Sheet Metal Plugs

Sheet Metal Plugs

Designed to cover holes in metal sheets – easy to fit and remove

Slottex Plugs

Slottex Plugs

Screw-on protection plugs applied or removed with screwdriver, spanner or socket; tightened manually with or without power tool; also available in HDPE


Ethylene Vinyl Acetate (EVA)

Flexible even in low temperatures, EVA has good chemical and stress-crack resistance and its properties work well for electrical applications. Good cushioning performance add an extra touch of protection, which is why it’s often used for handles. It’s especially an ideal material for plugging hydraulic hoses. Look for ones with ribs – these plugs provide a comfortable, snug fit without stretching the hose.

EVA is also excellent at protecting applications from dust ingress and damage.

Generally, EVA material offers:

Tensile Strength

0.05 - 0.2 N/mm²

Notched Impact Strength

No break Kj/m²

Thermal Coefficient of Expansion

160 - 200 x 10-6

Max Cont Use Temp

55˚C - 65 ˚C / 131˚F - 149 ˚F

Density

0.926 - 0.950 g/cm3

Resistance to chemicals:

Dilute Acid

Excellent

Dilute Alkalis

Excellent

Oils and Greases

Good

Aliphatic Hydrocarbons

Excellent

Aromatic Hydrocarbons

Poor

Halogenated Hydrocarbons

Poor

Alcohols

Excellent

Pull-Tab Caps

Pull-Tab Caps

Good tensile strength, toughness and increased flexibility

Caps in hand

Polypropylene (PP)

Polypropylene caps are known for good impact strength, cost effectiveness, and pliability. The material is considered tough, though it can act with elasticity. It doesn’t suffer stress-cracking problems. It has excellent fatigue resistance, retaining its shape after a lot of torsion, (which is one reason why it’s a great material for hinges). Polypropylene also offers excellent electrical resistance, so it’s often used in electronics. Not suited for freezing temperatures, where it can become brittle.

Generally, Polypropylene material offers:

Tensile Strength

0.95 - 1.30 N/mm²

Notched Impact Strength

3.0 – 30.0 Kj/m²

Thermal Coefficient of Expansion

100 - 150 x 10-6

Max Cont Use Temp

65˚C / 149˚F

Density

0.905g/cm3


Resistance to chemicals:

Dilute Acid

Very good

Dilute Alkalis

Very good

Oils and Greases

Moderate (variable)

Aliphatic Hydrocarbons

Poor

Aromatic Hydrocarbons

Poor

Halogenated Hydrocarbons

Poor

Alcohols

Very good

Threaded O-ring Plugs - UNF Threads

Threaded O-ring Plugs - UNF Threads

Compressing flange lip and O-ring for a watertight seal


Polyvinyl Chloride (PVC)

PVC is a very durable and long-lasting material. It’s also flexible, and as a cap or plug, this means they’re easy to fit and provide an excellent seal. PVC won’t crack or shred, as hard plastics can do, leaving residue on the area they’re meant to protect from contamination.

PVC can withstand high temperatures, making these caps and plugs good for all masking applications except blasting. Its chemical resistance makes it especially suitable for plating. It’s also an insulative material, which makes it a good choice for enclosures with electrical applications.

Generally, PVC material offers:

Tensile Strength

2.60 N/mm²

Notched Impact Strength

2.0 – 45.0 Kj/m²

Thermal Coefficient of Expansion

80 x 10-6

Max Cont Use Temp

65˚C / 149˚F

Density

1.38g/cm3

Resistance to chemicals:

Dilute Acid

Very good

Dilute Alkalis

Very good

Oils and Greases

Good (variable)

Aliphatic Hydrocarbons

Very good

Aromatic Hydrocarbons

Poor

Halogenated Hydrocarbons

Moderate (variable)

Alcohols

Good (varaible)

Flexible End Cap

Flexible End Cap

Provides tight fit for metric, BSP and UNF threads

Pull Tab Cap

Pull Tab Cap

Good tensile strength, toughness and increased flexibility; also available in EVA

Caps in use

Polyolefin

HDPE, LDPE and PP are polyolefins. See those specific materials for guidance.

Thermoplastic elastomers (TPE)

A thermoplastic elastomer, TPE is considered more of a rubber by some manufacturers because of its characteristics. Dense, flexible and soft, TPE offers excellent weather and ozone resistance. With good tear and abrasion resistance, TPE also has excellent flexural fatigue resistance and high impact strength.

Generally, TPE material offers:

Tensile Strength

0.5 - 2.4 N/mm²

Notched Impact Strength

No break Kj/m²

Thermal Coefficient of Expansion

130 x 10-6

Max Cont Use Temp

95˚C / 203˚F

Density

0.91 - 1.3 g/cm3


Resistance to chemicals:

Dilute Acid

Excellent

Dilute Alkalis

Excellent

Oils and Greases

Excellent

Aliphatic Hydrocarbons

Excellent

Aromatic Hydrocarbons

Poor

Halogenated Hydrocarbons

Poor

Alcohols

Excellent


Hose Washer Caps

Hose Washer Caps

Keeps hose or tube ends from sliding over fittings; also available in LDPE

Rubber

Ethylene Propylene Diene Monomer (EPDM)

Used mainly as a masking product, EPDM is versatile enough to also act as a protection solution. It’s generally a less expensive alternative to silicone. It has excellent weather resistance, which is why it’s popular as a roofing material in construction. The automotive, oil and gas industries like caps and plugs made from EPDM for its resistance to acids and alkalis. EPDM’s flexibility makes it an ideal masking solution for sealing round and irregular shapes.

Generally, EPDM material offers:

Resistance to weather and UV rays

Excellent

Water resistance

Excellent

Chemical resistance

Excellent

Tear resistance

Moderate

Resistance to gas permeability

Excellent

Resistance to ageing due to steam

Excellent

Compatibility with ketones

Excellent

Compatibility with alcohols*

Excellent

*EPDM has poor compatibility with the alcohol Hexyl

Resistance to chemicals:

Temperature Range

-40°C to 150°C / -40°F to 302°F

Tensile Strength Elongation

500-2500 P.S.I 600% Maximum

Durometer Resilience / Rebound


30-90 Shore Good
Masking Straight Cap

Masking Straight Cap

Masks threaded or non-threaded components during finishing processes; also available in silicone

Masking Cone Cap and Plug

Masking Cone Cap and Plug

Can be used as a cap or plug in masking processes

Caps on pipes

Silicone

Silicone is excellent at resisting high temperatures, making it the ideal material for masking. An excellent example: silicone tapered plugs. However, silicone’s abrasion resistance is poor, though it can stand up to repeated production runs and conditions without wearing, breaking or degrading. And while it is ill-suited as a vibration insulator, it’s an excellent choice as an electrical insulator. Silicone’s flexibility allows for easy installation in the masking process, while providing an airtight seal.

Generally, Silicone material offers:

Resistance to weather and UV rays

Poor

Water resistance

Excellent

Chemical resistance

Very good (Variable)

Tear resistance

Poor

Resistance to gas permeability

Poor

Resistance to ageing due to steam

Poor at temperatures over 150°C / 302°F

Compatibility with ketones

Poor to fair

Compatibility with alcohols*

Poor


When not to use Silicone

For protective purposes. Only use for masking

Resistance to chemicals:

Temperature Range

-55°C to 250°C /-67F° to 482°F

Tensile Strength Elongation

Maximum 11 N/mm² 100%–1100% Maximum

Durometer Resilience / Rebound


10-90 Shore A Good


USB & RJ Plug - USB-B Connector Type

USB & RJ Plug - USB-B Connector Type

Protects unused connector ports on electrical components

Masking Star Tubes

Masking Star Tubes

Masks long studs and pins where caps are too short

Masking Pull Plugs

Masking Pull Plugs

Masks threaded and plain through-holes; flexible to allow slight variation in different sizes

Click on the image below for the full masking guide:

Guide to masking solutions

Thermoplastic rubber (TPR)

Lightweight with good tear strength, TPR has qualities that combine the properties of rubber with the moulding capabilities of thermoplastics. It holds its shape and comes in varying levels of flexibility and has excellent electrical properties. Good tear strength, reusable and recyclable, TPR is an ideal solution for masking protection.

Generally, TPR material offers:

Resistance to weather and UV rays

Excellent

Water resistance

Excellent

Chemical resistance

Excellent

Tear resistance

Good

Resistance to gas permeability

Excellent


Resistance to chemicals:

Temperature Range

-40°C to 95°C /-40°F to 203°F

Tensile Strength Elongation

500% - 620%

Durometer Resilience / Rebound

20 Shore OO to 85 Shore D

Parallel Protection Plug

Parallel Protection Plug

Protects connectors while providing clean finish; also available in LPDE, vinyl and PVC

Side Pull-Tab Plug

Side Pull-Tab Plug

Easy removal, even in difficult positions; also available in LDPE

Flexible End Cap - Acid Resistant

Flexible End Cap - Acid Resistant

Hanging tab to work with round wire hooks and other support wire hooks

Paper

Caps and plugs made of crepe paper are a low-cost alternative to silicone. Used for masking in painting and powder-coating applications, it can stand up to high temperatures. Made from a blend of virgin pulp and post-consumer recycled paper, it’s a good option when you need environmentally friendly solutions.

Generally, crepe paper has:

Temperature Range

204°C /399°F

Tapered Paper Caps

Tapered Paper Caps

Good flexibility, easily stretching to cover a surface for masking

Paper Masking Plugs

Paper Masking Plugs

Does not promote condensation; 100% recyclable

Material vs chemicals

It’s critical to choose a general-protection material capable of standing up to chemicals. Chemicals can include anything from water to acid, so no matter what your application’s environment, you need to carefully consider the material you use. To learn more, check out Chemical resistance, caps and plugs.

Materials vs shock vibrations

During transport, caps and plugs are vulnerable to damage due to bumps and falls. This is why choosing a material with shock absorption is critical. Find out more in Caps and plugs, shock absorption and preventing damage in transit.

What exactly is shore hardness?

The shore hardness of materials is important for your application. Get it wrong, and your application could fail. Check out everything you need to know in What’s shore hardness and why should you care?

Why Essentra Caps and Plugs? Video

Turn to the experts for help in protecting your application at any – or all – stages of your product’s journey, including manufacturing, masking, transportation, storage and end use.

Download free CADs and try before you buy

Free CADs are available for most solutions, which you can download for free. You can also request free samples to ensure the solutions you’ve chosen are exactly what you need. If you’re not quite sure which product will work best for your application, our experts are always happy to advise you.

Request your free samples or download free CADs now.

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