Post Office Sponge Gaskets

Thousands of bespoke gaskets are manufactured and supplied by Advanced Seals & Gaskets Ltd on a daily basis, not only using the standard sponge, foam and rubber materials, but also other unique and specialist materials one of which is “Post Office Sponge” or orange open cell natural sponge.

Post office sponge is manufactured in blocks of various sizes and thicknesses up to 80mm, which vary depending on density which we can split down to as little as 1.5mm thick and convert into a range of finished products including cut gaskets. Our Post office sponge gaskets are produced on-site using drawings, samples or measurements provided by our customers, from a simple picture frame gasket to more complex shapes with cut-outs, notches or bolt-holes.

Whether it’s a one off sample or a multi-thousand batch run, we have a machine designed to quickly and accurately produce perfectly formed gaskets everytime, supplied in a plain finish, laminated in layers to create other thicknesses, laminated to other materials or coated with a choice of self-adhesives and foils prior to the gaskets being cut.

Product Enquiry

For information on Post Office Sponge Gaskets please complete the following quick enquiry or call us on +44(0)1384 252555.






    Characteristics of Using Post Office Sponge Rubber

    • Colour: Orange
    • Structure: Open cell (fine or medium)
    • Density: 140 to 600 Kg/m3
    • Temperature Range: -40ºC - +80ºC
    • Tensile Strength:  0.23 N/mm2 - 1.2 N/mm2 approx (vary between densities)
    • Elongation at Break:   455% - 817% (vary between densities)
    • Resistances (Ozone/Acids/Alkalis/oils/fats/solvents): Not resistant 
    • Flammability:  Highly flammable 

    Full technical data can be supplied upon request,
    or downloaded from our online portal.

    Help and guidance

    If you would like to speak to a representative to discuss your specific application or requirements please call our sales office direct on 01384 469100, alternatively you can send an E-mail. Simply click on the link and forward us your details along with your question and we will contact you immediately.

    Samples - Technical Post Office Sponge Gaskets

    Samples can be submitted for testing upon request.

    Call now for sample requests or further help.

    What are Post Office Sponge Gaskets?

    Orange open cell Sponge Gaskets sometimes come in the form of a strip or pad but are generally an intricately cut shaped piece of material placed between two surfaces to create a low pressure seal preventing the leakage of liquids or gas and to seal against the intrusion of dust and debris.  Post office sponge materials are manufactured using high quality natural rubber, and are available in a range of densities from 160kg/m3 to 600kg/m3, with a choice of pore sizes creating a selection of very soft or very firm materials making each gasket suited for use in different applications. Orange open cell natural sponge is recognisable by its bright orange colouration and the visible cell structure which is designed to be absorbent to hold liquids within it, but under enough compression can create a watertight seal.

    Why use Post Office Sponge Gaskets?

    Post Office sponge is not resistant to oils, acids or alkalis, therefore these gaskets are limited for use and unsuitable in certain industrial or automotive applications, however perfect for wet applications, labelling, packaging and even to create vacuum lifting seals.  Open cell post office sponge gaskets can also be used as air, dust to some extent moisture sealing gaskets when under enough compression to cause the cells to squash down enough to stop anything passing through.

    As with many other types of block foam, post office sponge can be split down and supplied as sheets, or further converted into a range of finished usable products including gaskets.  Post office sponge has been developed so that it can be produced in a choice of densities, pore sizes and firmness in order for it to be utilised in a wide range of applications depending on the amount of compression and moisture absorption required.

    Benefits of Using Open Cell Natural Sponge Rubber

    • Good abrasion resistance
    • Soft and flexible to seal around uneven or complex shapes
    • open cell structures also allows for water absorption
    • Excellent recovery following repeated compression
    • Good tear resistance

    Other Grades of Sponge Materials Available

    • EPDM - medium, firm, semi-open cell, high temperature
    • Neoprene - FR, medium, firm
    • Silicone
    • Polyurethane
    • Open Cell industrial sponge

    The Advantages of Using Post Office Sponge Gaskets

    Gaskets which are cut from post office open cell natural sponge offers numerous advantages, available in a choice of soft- feel or very firm materials with an open cell structure making them perfect for use in wet applications for water absorption for example in within packaging applications where these components help protect goods from impact damage or liquid spillages,whilst allowing for the circulation of moisture and gas when the application requires it. As this material catches liquid and holds it - it’s perfect for applications which then re-use the retained moisture such as paint pads, or floats used for plastering and tiling, etc. Post office sponge gaskets can be manufactured in a range of thicknesses, all offering excellent compression recovery particularly when it’s used for repetitive loading and distortion applications such as packaging and vacuum lifting. When subjected to enough pressure, the open cell structure in these gaskets will compress enough to behave like a closed cell material where they can seal against the ingress or dust, air and to some extent moisture.

    Have a Question About Post Office Sponge Gaskets?

    Please contact us using the form below or by calling us on +44(0)1384 252555.