Chemraz 633 vs Perlast G90A Comparison

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Reviewed by MLC Editorial Team | 7 June 2026

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Chemraz 633 and Perlast G90A are both perfluoroelastomer (FFKM) compounds used in chemical, refinery, and process applications. Chemraz 633 vs Perlast G90A They share similar chemistry but differ on temperature ceiling, hardness, and intended service. This page compares the two side-by-side and explains when to specify each.

Side-by-side comparison

Property	Chemraz 633	Perlast G90A
Manufacturer	Greene Tweed	Precision Polymer Engineering
Compound	633	G90A
Maximum continuous temp	327°C	270°C
Minimum temp	0°C	0°C
Hardness	90 Shore A	90 Shore A
Colour	Black	Black
Typical applications	Oil and gas, high-pressure valves	Oil and gas valves, RGD service

When to specify Chemraz 633

Chemraz 633 suits oil and gas and similar service. Continuous temperature window is 0°C to 327°C, hardness 90 Shore A. Manufactured by Greene Tweed.

When to specify Perlast G90A

Perlast G90A suits oil and gas valves and similar service. Continuous temperature window is 0°C to 270°C, hardness 90 Shore A. Manufactured by Precision Polymer Engineering.

Key differences

Temperature ceiling: Chemraz 633 runs 57°C hotter (327°C vs 270°C). Specify the higher-rated compound when continuous service is above 270°C.
Hardness: Both are 90 Shore A, so groove design and squeeze percentage are interchangeable.
Manufacturer: Chemraz 633 is from Greene Tweed; Perlast G90A is from Precision Polymer Engineering. Lead time and UK availability vary by brand.
Cost: FFKM pricing varies by manufacturer, batch size, and stock position. Both compounds are at the premium end of elastomer pricing (£30 to £500+ per O-ring depending on size).

Get a UK quote on either compound

Get a quote for Chemraz 633 vs Perlast G90A Comparison

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Related pages

References

Greene Tweed - Chemraz 633
Precision Polymer Engineering - Perlast G90A
BS 1806
ISO 3601

Frequently Asked Questions

Can I substitute Chemraz 633 for Perlast G90A?

Yes, Chemraz 633 and Perlast G90A are both FFKM compounds with overlapping chemical compatibility. Verify your specific fluid against both manufacturers' compatibility tables before substitution. Temperature window, hardness, and certifications may differ.

Which is hotter: Chemraz 633 or Perlast G90A?

Chemraz 633 has a higher continuous temperature ceiling (327°C vs 270°C, a 57°C difference).

Which costs less: Chemraz 633 or Perlast G90A?

FFKM compound pricing depends on manufacturer, batch size, certifications, and current stock position rather than headline brand. Both compounds are at the premium end of elastomer pricing. Get current UK quotes on both before specifying.

Where can I buy Chemraz 633 or Perlast G90A in the UK?

Both compounds are supplied in the UK by independent FFKM seal specialists carrying multiple manufacturer lines. Lead time is typically 2-5 working days for stock BS 1806 / AS568 sizes, 4-8 weeks for custom-moulded sizes.

Independent UK engineering trade publication. Company profiles cross-referenced with Companies House.

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