Kalrez Alternative, FFKM Cross Reference
Every major FFKM brand is the same polymer family. Here is how to swap to an equivalent compound without gambling on performance.
In one line: Kalrez is a brand of FFKM, not a unique material. Chemraz, Perlast, Simriz, Isolast and Markez are the same polymer family, so an equivalent compound cross referenced on temperature, chemistry, compression set and approvals performs like for like, usually for less money.
The reason sites stay locked to one brand is rarely technical. A compound got specified years ago, it went on the approved vendor list, and nobody revisited it. Meanwhile the price climbed and the lead time stretched.
A cross reference done properly is a matching exercise on properties and paperwork, not a swap by part number. Get that right and you gain a second qualified source without changing how the seal behaves.
Who Makes FFKM, and Under Which Name
| Brand | Owner | Notes |
|---|---|---|
| Kalrez | DuPont | The best known FFKM brand, widely written into legacy specifications. |
| Chemraz | Greene Tweed | Broad FFKM range including semiconductor and food contact compounds. |
| Perlast | Precision Polymer Engineering | UK produced FFKM, strong in explosive decompression and process duty. |
| Simriz | Freudenberg | FFKM range covering chemical, pharmaceutical and high temperature duty. |
| Isolast | Trelleborg | FFKM compounds across process, oil and gas and hygienic applications. |
| Markez | Marco Rubber | FFKM compounds commonly used as an equivalent source. |
All brand names and trademarks are the property of their respective owners. Acumen Seals & Pumps Ltd is not affiliated with, endorsed by, or a distributor for these brands. We supply cross referenced FFKM compounds matched on published properties.
How We Cross Reference
1. Send what you buy today
Brand, compound number, size and annual usage. A photo of the bag label is enough to start.
2. Tell us the duty
Fluid or mixture, concentration, maximum temperature, pressure, gas service, cleaning cycles.
3. We match on properties
Temperature rating, chemical resistance, compression set, hardness, approvals and any ED test evidence.
4. You get a like for like quote
Compound recommendation, certification, price and lead time, with an honest note if a cheaper material will do.
Not sure FFKM is the right material in the first place? Start with FFKM vs FKM or check your fluid on the chemical compatibility chart.
Kalrez Alternatives, Questions Answered
Is there an alternative to Kalrez?
Yes. Kalrez is a brand of FFKM, not a unique polymer. Chemraz, Perlast, Simriz, Isolast, Markez and several independent compounders all produce perfluoroelastomer to the same polymer family. A properly cross referenced FFKM compound gives like for like performance in the same duty, usually at a lower price and often with a shorter lead time. All trademarks belong to their respective owners.
How do you cross reference a Kalrez grade?
On properties, not on a lookup table. We take the existing grade, the fluid, the temperature, the pressure, whether rapid gas decompression is involved and any approvals you need, then match a compound with equivalent temperature rating, chemical resistance, compression set and hardness. A number to number swap without the duty behind it is a guess.
What is the difference between Kalrez and Chemraz?
Both are FFKM. They differ in compound formulation, filler and cure system, which changes temperature limits, compression set and approvals grade by grade. Neither brand is universally better. The right question is which specific compound suits your duty, not which badge is on the bag.
Will a Kalrez alternative void my warranty or approval?
Not usually, but it depends on the paperwork. If your equipment or process approval names a specific compound, that has to be respected or formally revised. If it specifies a performance standard such as FDA, USP Class VI, 3A, NORSOK or an explosive decompression rating, we supply a compound carrying that certification with the documentation.
How much cheaper is an FFKM alternative?
It varies with size, grade and quantity, and we will not quote a saving we cannot back up. What we can say is that independent FFKM compounds are routinely less expensive than the best known brands for equivalent performance, and lead times are often shorter. Send the part and we will price it against your current spend.
Do you supply Kalrez equivalent O-rings in non standard sizes?
Yes. Standard AS568 and metric BS ISO 3601 sizes from stock ranges, plus oversize and bespoke rings made to your groove dimensions. If you have the groove but no part number, send the groove diameter and cross section.
What is an approved vendor list problem with FFKM?
Many sites are locked to one brand because it was specified years ago and nobody revisited it. Adding a second qualified FFKM source is a purchasing and quality exercise, not a technical one: match the compound properties, get the certification, run it on a non critical duty first, then add it to the AVL.
Can you match an explosive decompression resistant grade?
Yes. Rapid gas decompression grades exist across FFKM brands. Tell us the gas, the pressure, the decompression rate and any NORSOK or ISO test requirement, and we will match a compound with the right test evidence rather than a general purpose ring.
How long does a cross reference take?
Usually the same day for a straightforward duty. Send the current part number, grade, fluid and temperature and you will get a recommendation and a price, plus an honest note if FFKM is more material than the job needs.
What if FFKM is not the right material at all?
We will tell you. A large share of the FFKM enquiries we see are solved by a different FKM grade, a hardware change to the clearance gap, or fixing an installation problem. Selling you the most expensive elastomer on the market when a cheaper one lasts just as long is not a business we want.
Send the part number, get a straight answer
Brand, compound, size and duty. Same day cross reference on most standard grades, with certification where you need it.