Test Plugs – Low Pressure – Nylon

An Easy, Simple, Positive Seal!

HFT Pipestoppers® Nylon Plugs are suitable for a myriad of applications and range from 0.5 to 6″ (12 to 150 mm). They are mostly used for leak testing of pipework fabrications, or simply to prevent the ingress of dirt, vermin or other unwanted material. However, there are over 100 different applications for these plugs. HFT Pipestoppers® Nylon Plugs are constructed from injection-moulded, high-grade nylon components and rubber rings. They have the advantages of being light, non-rusting, low cost, provide very fast and effective sealing, easy to expand and can be dismantled for cleaning purposes.

HFT Pipestoppers® Nylon Plugs are constructed of high-grade Nylon 6 which has considerable wear characteristics and makes them stronger and more robust than other plastic plugs. Nylon 6 is an engineered polymer which is resistant to salt water corrosion as well as to many other chemicals.

Effective sealing is simple, insert the plug into a pipe or cylindrical opening and tighten the wing nut clockwise. The rubber ring will expand and provide a positive seal. To remove simply reverse the process.

Testing and sealing of all pipes, pipe joints and pipework assemblies can be done with the HFT Pipestoppers® Nylon Plugs.

Other applications include sealing holes in castings, tanks, other assemblies for spraying and blasting to protect the insides, maintenance and installation of swimming pool and water spa pipework, for use as ‘Scupper Plugs’ in ships, for telecommunication pipelines and pipework up to 6″, as radiator test plugs for cars and commercial vehicles, as heat exchanger tube plugs, etc.

The standard seals are made from natural rubber. However, other available options are:

• Natural Rubber
• Silicone
• Nitrile
• Neoprene
• Viton

HFT Pipestoppers® Nylon Testing Plugs can be supplied in specialised Plug Kits to suit specific applications.


The HFT Pipestoppers® Nylon Plugs can be supplied with a hollow shaft for screwing on standard hose connections, or for using our own fixed nipple caps, or the free nipple and cap assemblies. The smaller size plugs can be supplied with solid shafts for greater pressure testing capabilities.

Size range for the two types are:

A hollow shaft version with eleven sizes
from 0.5 to 6″ (12 to 150 mm)

A solid shaft version with five sizes
from 0.5 to 1.5″ (12 to 38 mm)


All plugs have:

Threaded central spindle, shaft or waterway onto which a top and bottom plate are mounted, with a rubber ring between them. Wing nut screws down onto the top plate which compresses the ring until the plug is sealed in the hole/cavity.

Optional rubber seals can be provided manufactured from different materials for resistance to higher temperatures or petrochemical vapours and fluids:

  • Natural Rubber
  • Silicone
  • Neoprene
  • Nitrile
  • Viton

Hollow shaft plugs from 0.5 to 1.5″ (12 to 37 mm) diameter have an outside thread of 8 mm and are provided with sealing caps. Sizes of 1.5″ (37 mm) and above are threaded with a 1/2″ BSP thread for the connection of industry standard nuts/hose fittings and are provided with a solid end cap seal. These plugs will provide airtight seals.

Optional end caps are available for the 1/2″ BSP threads, with fixed nipples/nozzles for hose connection or free nipples that can rotate when heavier hoses are used.

Nylon 6 is an engineered polymer which is resistant to salt water corrosion it is also resistant to many other chemicals. Along with natural rubber rings they provide a high quality leak tight seal in the selected orifice.

Special Versions

Where preferred, we can provide customers with coloured nylon to meet specific requirements. Company names and logos can be included on the mouldings as specials too subject to quantity.