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Autoclave Seals

William Johnston & Company Limited is recognised for technical ability, customer service and quality accreditation to ISO 9001:2015. We are experienced at partnering with customers to replicate or improve upon original components and equally as comfortable producing to drawings, adding great value with our sealing solutions on new or existing products.

We supply custom ‘rubber’ injection mouldings, compression and transfer mouldings and extrusions with recognised approvals for Utility, Automotive, Defence, oil & gas, health industries.

Autoclave Door Seals are supplied in high quality, durable FDA silicone. They are offered as:

• Endless extrusion,
• Press joined ‘O’ Rings,
• Mitre cut square, rectangular or profile seals,
• Moulded one piece components.
• Cut from flat sheet.

We have an extensive range of Autoclave seals available in a wide range of materials, from our general-purpose silicone rubber compounds that will cope with temperatures up to 200°C to silicone rubber grades which are rated up to 300°C: including a steam resistant grade for use in steam autoclave applications complimented with our Anti-Friction (AF) process, which can be applied to any of our Silicone Rubber grades. This process overcomes stickiness and static which are common issues associated with silicone rubber and can cause seals to pull from their housing when opening doors and the pick-up of dirt, making them difficult to keep clean.

Rubber Type Approval Grade Temperature Range (°C)
Silicone FDA General Purpose -60 TO +300
Silicone FDA Steam < 250
Silicone FDA General Purpose with Anti Friction -60 TO +300
Silicone FDA Steam with Anti Friction < 250

We have an extensive catalogue of common profiles which can be viewed by downloading the associated Pdf files. Rapid prototyping can also be offered if we don’t have the specific section that you need. This can usually be achieved within 2 weeks.

Shore A ScaleRubber hardness is measured using the Shore A scale and we offer:

40° Shore A hardness Autoclaves seals,
50° Shore A hardness Autoclaves seals,
60° Shore A hardness Autoclaves seals,
70° Shore A hardness Autoclaves seals.


Anti Friction process

The Anti Friction process can be applied to all extruded profiles, including D sections, P sections, Cord & Tubing. It can also be used on our Mouldings, Washers, Gaskets & other parts.

Parts that have the AF process applied to them have a pleasant smooth surface finish, with highly reduced dirt attraction. Contacting surfaces have less friction and this can ease the fitting of seals. The non-stick surface means components are easily separated, even after extended periods of contact; it also helps the life of the seal when in constant contact with moving parts.

The Anti Friction process does not affect the mechanical properties of our silicones, nor does it affect the colour.

The Anti Friction treatment does not affect the FDA extraction test results, so grades that are FDA compliant prior to the treatment are still FDA compliant afterwards.

Some of the grades we can process with the treatment include: General purpose, food grade, high strength, platinum cured, steam resistant and flame retardant.

Contact us using the form below with your requirements to see how you could benefit from utilising our anti-friction sealing technology.

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Contact William Johnston & Company Limited

For more information about our Autoclave Seals that are available world wide, contact us on +44 (0)141 620 1666, Email us or simply complete our online Enquiry Form.


Failure to select the correct materials or products can result in damage to plant and equipment and personal injury. In specific applications, particularly where critical conditions exist, we suggest you contact us and we will consider with you the most suitable material or product. However, information supplied by William Johnston & Company Limited is intended only as technical co-operation and as a guide to the various uses of different products. No warranty is given in respect of information or recommendations by William Johnston & Company Limited which are only given for guidance and without any guarantee. The customer must satisfy themselves on the suitability of the material or product for the intended purpose. The correct fitting of products is the responsibility of the customer.

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