Rubber versus metallic seals

DP Seals Smart Diaphragm Seal

Why choose rubber versus metallic seals?

When it comes to comparing rubber versus metallic seals for any joint solutions some of the benefits that rubber can provide are as follows:

  • Improved resistance and longer cycle life. Rubber joints can exceed 50,000 cycles vs. 2,000 cycles of metallic
  • No vibration fatigue. Rubber joints act as a dampener.
  • This dampening can also help to reduce noise.
  • No danger from stress corrosion. Metallic joints are subject to irregular cracks from stress and corrosion.
  • Resistance to external damage.
  • No corrosive electrolytic action. Metallic requires costly gaskets.
  • Shock resistance. Rubber absorbs shock well.
  • More flexibility in less space.
  • Simultaneous axial and lateral deflection.
  • No internal sleeves required.
  • Lightweight. Rubber has obvious advantages here.
  • Very low movement forces required.
  • High resistance to abrasion and erosion.
  • Compound stability where extreme hot or cold temperatures are experienced.

Get an unbiased view – we promise!

When making these decisions about your requirements DP Seals Technical Team are always on hand to help advise if rubber is better suited or not to your specific application. Simply contact us via our Contact page or email with the details of your specific application and one of our team members will be happy to help you.

DP Seals Achieves Cyber Essentials Certification

DP Seals takes cyber security seriously and to demonstrate our commitment we have been working towards cyber essentials certification provided by the National Cyber Security Centre.

We’re pleased to say this has now been achieved, providing confidence to our staff and customers that we have protection against a wide variety of the most common cyber attacks.

To achieve this certification we have demonstrated, amongst other things, that:

  • we are working consistently to secure our systems against cyber attack
  • we have cyber security measures in place
  • we have a clear picture of our cyber security level

Further information can be found on the Cyber Essentials Certification website.


Coronavirus statement

Based on the World Health Organization’s declaration that Coronavirus is a public health emergency of international concern we felt it was prudent to assess the risks to our business.

We can communicate that we do not have any materials, components, goods or services that are currently affected by closures imposed by the Chinese government due to the Coronavirus epidemic.

Therefore, we have no evidence of impacts on supplies or production operations. Nevertheless, we cannot guarantee that any shortages of raw materials coming from Europe or Far East will occur in the future.

Any developments on the matter will be monitored and communicated, if necessary. The latest information and advice from the UK Government can be accessed here.

Natural Versus Synthetic Rubber

Examples of DP Seals produced items

Natural and synthetic rubber both have their place

According to Statista there were 15.2 thousand metric tons of synthetic rubber and 13.2 thousand metric tons of natural rubber globally consumed in 2018. Indeed, although synthetic rubbers can provide a myriad of property improvements both have their place in respect to relative performance characteristics and cost.

Natural rubber

Natural rubber can only grow in tropical climates and doesn’t age well. Most natural rubber is produced from the softwood Hevea brasiliensis tree, which is native to Brazil. However there are several other species of trees and shrubs from which natural rubber is sourced.

It has a high tensile strength, higher tear resistance, low odour, and is resistant to fatigue from wear such as chipping, cutting or tearing. It also has tack, which means it can adhere to itself as well as other materials. This is particularly the case for steel cord which makes it an excellent material for use in tires. Natural rubbers are also a very popular choice in the Subsea, Oil & Gas field particularly.

On the down side natural rubber has only moderate resistance to damage from exposure to heat, light and ozone. It also contains natural proteins which may cause allergic reactions when placed in contact with human skin for prolonged periods.

Synthetic Rubber

Synthetic rubber is artificially produced from polymers in different varieties to mimic the properties of natural rubber. So, for many countries, it is easier to use.

In general, synthetic rubber offers better resistance to abrasion than natural rubber, as well as superior resistance to chemicals, fluids, ozone, electrical heat and the effects of aging. Many types of synthetic rubber are flame-resistant, so it can be used as insulation for electrical devices. It also remains flexible at low temperatures and is resistant to grease and oil. Because of this synthetics offer excellent potential and opportunities for applications in extreme temperatures and corrosive environments.

For more detailed information about specific compounds see our data sheets and chemical compatibility database or call our material technologists.

Cleaning Process

The Early Days

Our cleaning department has evolved over the years and become a major part in our production process. Steve Collinson started in the cleaning department 22 years ago and recalls the early days. He had an industrial tumble dryer, two slow speed rotating tub machines and very limited sizes of ceramic media. In addition there was one N-180 cryogenic machine using liquid nitrogen and aluminium oxide balls. This machine had an on/off switch and limited speed control. That was it!

DP Seals Early Cleaning Department

Steve would load the machine, leave it for about 15 minutes and hope that everything was okay and not smashed up when he returned. Next he would shovel out the seals, gaskets or mouldings complete with the cleaning balls and very carefully separate the two.

Entering the computer age

A couple of years later a new TS10 cryogenic machine was installed which was a big investment for the company . This changed everything dramatically as it was computer controlled and enabled much more accurate control of the whole process. A vast storage tank was installed outside the building which, to this day, still gets refilled by lorry every week.

Cryogenic Cleaning Machine

The TS10 has the ability to spin the drum at much faster speeds up to 6000 rpm. Liquid Nitrogen is sprayed into the tank until it has reached the desired operating temperature which is, on average, -75C.  This freezes the product, at which point media is blasted into the tank to remove excess flash. Once the process is complete the media is automatically separated and passed back into a storage tank. At this point the hatch can be opened and, whilst the drum rotates very slowly, the product slowly empties, saving a huge amount of time.

A flexible, modern approach

DP Seals recently added an even newer cryogenic machine and this has more than doubled the throughput of work. With the evolution of different cleaning medias we are able to clean very small, fragile parts in these two cryogenic machines.

Whilst these machines have transformed the control and speed of cleaning Steve still uses the variety of rotating tub machines to provide greater flexibility on how every product is cleaned.

Over the years the cleaning process at DP Seals has improved significantly and we’ll continue to invest to keep ahead of the game.


Which metals can be bonded to rubber?

Rubber To Metal Bonding

Almost any metal can be bonded to rubber

Provided that it can withstand the heat and pressures of the rubber moulding process almost any metal can be bonded to rubber. However, each metal has a different chemical composition that can react to the type of rubber being used.

Expert advice

An important step is to determine the best metal type and grade as well as the optimal type of rubber to specify for the application. DP Seals can advise on the best rubber material and develop custom compounds with additives to aid metal bonding.

Brassed off

One problematic material is brass, which contains lead that chemically counteracts rubber bonding. The softer, free-cutting brass materials have higher lead content and can be difficult to bond. Better bond strength can be achieved with the lowest possible level of lead content. Substrate preparation is absolutely key along with timely application of two coat bonding agent systems.

Additional support

If you need further advice download our free rubber to metal bonding guide and get in touch with our materials technologists.