Frequently Asked Questions

If you have a question you may be able to find what you want by using our search function in the website navigation header above. If that doesn’t provide you with what you want, below you’ll find some our most frequently asked questions.

DP Seals

Can you provide a catalogue of parts you currently supply?  

We do not produce a catalogue because we only supply custom rubber seals, gaskets and mouldings made to our customers’ drawings or specific to their individual application.


Why choose custom rubber parts over standard?  

Here are 9 reasons why custom rubber parts provide advantages over a standard alternative.

  1. Intricate applications necessitate them
  2. They provide greater sealing surface
  3. Lower friction
  4. Longer life
  5. Reduced maintenance and operational costs
  6. Improved quality of finish
  7. Overcoming hazardous environments
  8. Complying with regulations
  9. When you’re not sure what you really want

Find out more in our article


DP Seals

Which is the best material for my application?  

Whilst many material characteristics lend themselves to certain types of application there are often compromises to be made. You can get a general guide for which material might be best from using our chemical compatibility database , app or by taking a look at our datasheets. However DP Seals works with you to achieve higher levels of performance and longevity by developing custom blends that reduce the compromises you need to make. We suggest contacting us to discuss suitable materials for your specific application.

Within what temperature ranges can rubber work effectively?  

Some Silicones can perform at minus 100° degrees C and even lower. At the other end of the scale some compounds can withstand excursions to over 300° degrees C, depending on the grade used and compound formulation. Of course temperature range is only one consideration when designing a rubber seal, gasket or moulding so we recommend consulting with us to get advice on the best material for your application.

I don’t know what type of rubber to use?  

No problem. Tell us the application and the environment and DP Seals will work with you to advise the best compounds to use for your application.

What Is Shore Hardness?  

Shore hardness is the hardness value of the material. Different hardness values are more suitable for certain products than others and understanding this can help ensure you get the perfect product for your needs. For example, a Shore 10 hardness is very soft (Like a jelly baby) and a Shore 90 is very hard (Like a plastic).

What types of rubber materials does DP Seals use to make parts?

Amongst many other rubbers we can process, Nitrile, Silicone, EPDM, Viton®, Butyl, SBR , FFKM and Natural Rubber. We are also able to produce parts to specialist specifications.

Can you meet any special material requirements?

Yes. DP Seals manufactures rubber mouldings to FDA, UL, NSF and many other specifications. If the environment is harsh but no compound has yet been developed, DP Seals can formulate a compound to meet any required specifications for you. 

Is it possible to identify a rubber type when sending in a sample?  

This is something that we can get done for you by arranging for the rubber to be tested.

How does the hardness of rubber affect application design?  

Firstly, it should be remembered that rubber is a solid material. Therefore displacement is a key consideration. The harder the rubber the less space required. However the hardness of the rubber material chosen will also be influenced by how dynamic or static the moulding will be as well as many other considerations. Consult DP Seals for the best advice.


3D Printing & Prototyping +
DP Seals

Do you do Rapid Prototypes?

Yes. If you need parts quickly that do not need to meet your exact material requirement DP Seals can have parts for you within 10 days. This is an exceptional alternative to reduce cost and accelerate lead time.


Rubber to Metal Bonding+
DP Seals

Can you mould rubber-to-metal bonded items?  

Yes, we are happy to manufacture rubber mouldings with a metal insert. We can either source the metal ourselves or work with your free-issue items.

Why use rubber to metal bonding?  

There are many reasons for using rubber to metal bonding.
Some key reasons why you might choose to use rubber-to-metal bonding include the following:

  • Any part which requires a combination of the flexibility of rubber and the stability of metal.
  • Combining several parts into a single assembly.
  • Ensuring that critical functions will not fail due to a weak bond where they may if using a traditional adhesive.
  • Enhancing sound proofing and vibration control.
  • Sealing against organic solvents, sea and boiling water.

What are the steps in the rubber to metal bonding process?  

There are 5 key steps in the rubber to metal bonding process including:

  1. Part design geometry
  2. Preparation of the part
  3. Application of the bonding agent
  4. Moulding
  5. Testing

Read our article to find out more…

Which metals are suitable for rubber to metal bonding?  

Provided that it can withstand the heat and pressures of the rubber moulding process almost any metal can be bonded to rubber. Find out more in our article.


DP Seals

Can you provide ISO9001 accreditation?

We hold an AS9100 accreditation which Includes all of ISO 9001 quality management system requirements and specifies additional requirements for a quality management system for the aerospace industry.

We also hold ISO14001 and ISO 45001 and all of these are implemented across all our industrial manufacturing sectors. We have a copy of all our certificates available on our website, for supplier and customer reference.

How can design engineers be confident that the rubber mouldings provided will do their job over the lifetime of the product?  

Design engineers should be confident in the quality standards, testing (Dynamic and static), using a reliable compounder. At DP Seals we’ve formed long-standing partnerships with industry leaders who have processes in place to guarantee repeated consistency. In addition we have our own documented database detailing material and each process stage through to the finished item – and that’s for every component we produce.


Tool & Mould Making +
DP Seals

What are the lowest/highest tolerances DP Seals work to?  

At DP Seals we fundamentally use a closed cavity system of moulding which we have developed over many years. This allows us to control material very well and therefore maintain tight tolerances of up to two thousandths of an inch or 50 microns.

What are the key challenges to be aware of when working to achieve the right tolerances?  

When working with rubber we often find is that there is an expectation or even a default tolerance on drawings that can be biased toward metallic, machined or turned parts. Rubber is quite different, and due to its nature as a material, this must be taken into account. For example – shrinkage from the mould tool cavity.

Can the same mould be used for different levels of rubber hardness?  

Yes, within limits and depending on material type a given mould can be used to produce samples in numerous hardness grades. Through fine tuning it can then be refined to what suits the application best.


Design & Manufacturing+
DP Seals

I don't have drawings - can you still make the parts I need?  

We are able to work to customer drawings or samples. We can utilise existing CAD files or sketches and are able, in most cases, to reverse-engineer items from customer-supplied samples.

Can you manufacture coloured Rubber Mouldings?  

Yes, we are able to produce custom rubber mouldings in a variety of colours and do so for a number of customers. The colours include white, brown, grey, blue, red, green and yellow.  We are also able to colour match if you send us a sample of the colour required. We are also able to mix to a RAL or Pantone Code

What are your manufacturing capabilities?  

We specialise in transfer and compression moulding techniques.


DP Seals

What are the benefits of fluorination?  

The key benefit is greatly reduced coefficient of friction. Find out more in our article

What is fluorination?  

Fluorination is a permanent conversion of an object surface by reaction with fluorine gas under highly controlled conditions.


Quotes & orders+
DP Seals

What is your minimum order?  

Because all products are custom made, the minimum order will depend on how much the batch of rubber will yield for the part you are requesting. There is also where applicable a minimum order value of £150.00. Therefore, we are able to run small batches or large batches up to hundreds of thousands of parts.

Do you ship outside of the UK?

Our parts are used all over the world. However, we ask you to arrange the collection of the parts at your cost through your chosen carrier (Ex Works).

What is your lead time?  

This always very difficult to answer as it depends on many factors including delivery of the raw material to us, if there are any free issue parts involved etc. Sometimes we will agree with you to hold an amount of buffer stock for quick call off. We will be happy to discuss lead times with you when we have a better idea of your requirements.