Plugs and caps are used to protect or finish exposed ends of tubes and pipes to prevent damage to the threaded interiors, chipping, splitting or scratching to the outside. This can happen during storage, handling or transportation. Additionally, the sharp exposed ends of pipes can cause harm or hurt to people, hence fitting a plug or cap prevents such hazards.

Materials used are a variety of plastics and plastic compounds, rubber or silicone compounds in a range of densities, thicknesses, gauges and with features like temperature-resistance, resistance to weather, aggressive organic and inorganic chemicals, acids, oil, grease, solvents and water. Plastics are also smooth textured and if the caps or plugs are dome-shaped, they don't allow water to remain on their surfaces. The flexibility, elongation and structural strength and properties of plastics/rubber can be varied according to the function for which the plugs and caps are to be used. Some types of rubber may become distorted, swollen, brittle or soft when exposed to heat or chemicals, hence it is important to choose the right type of material for plugs and caps.

Plugs are available in a variety of designs:

Tapered: used to protect threaded interiors and they can function as both plugs and caps.

Flanged: design provides extra coverage over the edge of the pipe and wide or narror flange designs are available. These also function as both plugs and caps.

Tab: This design incorporates a pull-tab either at the side or center for easy removal. The tab can also have a label for instructions/product details etc.

Electrical connector: These plugs are designed to prevent dust, moisture, debris and grime from damaging electrical connectors. They have a flange design for easy removal in inaccessible areas.

Packaging tubes: This design is suitable for fitting at the ends of packaging tubes to provide protection while shipping documents and other scrolled items. They are usually lightweight and easy to remove and provide a snug fit. They can be designed as tamper-proof or tamper-evident plugs.

Special: Static dissipation and electrical conductivity requirements can be met by using plugs made of special static-free or conductive materials. They are usually color-coded for easy identification.

Caps are also available in similar configurations:

Generally, the shapes are round, rectangular etc, with shallow, long or ribbed designs. Apart from providing protection, caps are also used in paint-masking, planting and sand-blasting operations. Different shapes, sizes and colors are also available.

Grease-resistant caps and caps with tear-off tabs are used in special applications, while caps with vented pull-tabs and hanger caps are also available. Anti-roll caps provide protection while shipping and handling, while grab-tab caps make for easy removal. Threaded and non-threaded caps are also available.


Based on your requirements, you can purchase plugs and caps from your local hardware dealer or order them on-line.

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