Sealing Ring Kits

What are sealing ring kits?

Sealing ring kits are ready-made sets that give you a selection of O-rings, or everything needed to make your own, in one box. They save time and downtime by putting the right seal on hand when it is needed, instead of waiting for a single size to arrive. There are two main types: O-ring assortment kits, which contain a range of ready-made rings in common sizes, and O-ring splicing kits, which contain cord and tools to make custom rings of any size.

A typical sealing ring kit includes:

• A sturdy storage case with labelled compartments
• A selection of O-rings in common metric or imperial sizes, or lengths of O-ring cord in several section sizes
• A size chart or labels, so the right ring can be found quickly
• For splicing kits, the tools and adhesive needed to cut and join cord into rings.

Kits are made for quick repairs and maintenance.

• Assortment kits cover the sizes most often needed, so common leaks can be fixed straight away.
• Splicing kits let you make a ring of exactly the right size on the spot, which is ideal for large, unusual, or obsolete sizes.

Kits are available in different materials, with nitrile being the most common for general use.

Why are sealing ring kits essential?

A small O-ring can stop a whole machine. When a seal fails, waiting for the correct size to be ordered and delivered can mean hours or days of downtime. A sealing ring kit puts a full range of sizes, or the means to make any size, in the workshop or service van, so repairs can be made immediately.

Kits also save time searching through loose stock, keep seals clean and organised, and make it easy to see when popular sizes need restocking. For maintenance teams, mobile engineers, and workshops, they are one of the most practical items to keep on the shelf.

Typical users and applications include:

• Maintenance departments and plant engineers
• Mobile and field service engineers
• Vehicle, plant, and agricultural workshops
• Hydraulic and pneumatic repair
• Plumbing and heating engineers
• Pump and compressor servicing
• Production lines needing quick seal changes
• Making custom seals for large or obsolete sizes

The main types of sealing ring kits

• Metric O-ring assortment kits - A selection of ready-made O-rings in common metric sizes, sorted by size in a compartment case.
• Imperial O-ring assortment kits - A selection of O-rings in common imperial sizes, often using standard British Standard (BS) sizes.
• O-ring splicing kits - Contain O-ring cord in a range of section sizes, typically with a cutting tool, a joining jig, and adhesive, so custom rings of any diameter can be made. For example, a nitrile splicing kit might cover cord sections from 1.78mm to 8mm.
• Material-specific kits - Kits in materials other than nitrile, such as FKM for heat and chemical resistance, for specialist maintenance.

How to choose the right sealing ring kit?

• Metric or imperial - Choose a kit that matches the equipment you maintain. Metric kits suit most modern European and Asian machinery, while imperial kits suit older British and American equipment.
• Ready-made or splicing - Choose an assortment kit if you mostly need common sizes quickly. Choose a splicing kit if you need large, unusual, or obsolete sizes, or want to make any size on demand.
• Material - Choose nitrile for general use with oils and greases. Choose other materials, such as FKM, where heat or chemicals are involved.
• Size range - Check the kit covers the section sizes and diameters you use most often.
• Refills - Check whether individual sizes or cord lengths can be bought separately to restock the kit.

Essential references and specialised ranges

How the numbering works:

Sealing ring kits are usually referenced by type, material, and size range or number of pieces. For example:

Nitrile O-ring splicing kit, 1.78mm to 8mm cord = a nitrile splicing kit covering cord sections from 1.78mm up to 8mm

Metric nitrile O-ring kit, 400 pieces = a box of metric nitrile O-rings in a range of sizes

Imperial BS O-ring kit = a box of O-rings in standard British Standard imperial sizes

O-rings inside the kits are referenced in the usual way, by inside diameter and section, or by BS number for imperial sizes.

Suffixes:

NBR = nitrile rubber

FKM = fluoroelastomer

70, 90 = hardness on the Shore A scale

Suffix codes vary between manufacturers, so check the supplier’s catalogue for the exact meaning.

FAQ - All you need to know about sealing ring kits

What is the difference between an assortment kit and a splicing kit?

An assortment kit contains ready-made O-rings in set sizes. A splicing kit contains O-ring cord and tools, so you can cut and join the cord to make a ring of any size you need.

How do I use an O-ring splicing kit?

Measure the groove or the old ring, work out the length of cord needed, and cut the cord squarely with the cutting tool. Use the jig to hold the ends in line, apply the adhesive, and hold the joint together until it sets. Check the joint is smooth before fitting.

How do I work out the length of cord needed?

Add the inside diameter of the ring to the cord section, then multiply by 3.14. For example, for a 60mm inside diameter ring in 3mm cord: (60 + 3) x 3.14 = about 198mm of cord.

Can I buy refills for my kit?

In many cases, yes. O-rings and O-ring cord are usually available separately, so popular sizes can be restocked as they are used.

How should I store an O-ring kit?

Keep the kit closed, in a cool, dry place away from direct sunlight, heat, and electrical equipment that produces ozone. This helps the rubber stay in good condition for longer.

How do I find the right O-ring in my kit?

Measure the inside diameter and section of the old ring, or the groove it fits, and compare these to the size chart or labels in the kit. For imperial kits, match the BS number where possible.

How can I tell if O-rings from a kit are past their best?

Warning signs include:

• Rubber that has become hard, brittle, or sticky
• Cracks appearing when the ring is gently stretched
• Rings that have lost their round shape
• Fading or surface cracking from exposure to light or heat