Assembly grease
#1 What is assembly grease?
An O-ring should always be lubricated with a suitable “assembly grease” before installation. This makes installation easier and also promotes the longevity of the O-ring.
Assembly greases for O-rings are essentially divided into two categories
1. mineral oil base
2. silicone base
Now the question arises: Which assembly grease do I use for which material?
As an answer to this question, we have compiled a table with the most important O-ring materials as an overview.
#2 Which assembly grease for which O-ring material?
Material | Mineral oil base | Silicone base |
|---|---|---|
NBR | Resistant | Resistant |
EPDM | Not resistant | Resistant |
SILICONE | Resistant | Not resistant |
FKM | Resistant | Resistant |
FEP coated | Resistant | Resistant |
PTFE | Resistant | Resistant |
FFKM (ECOLAST) | Resistant | Resistant |
Conclusion: The wrong assembly grease can have serious consequences, especially with silicone and EPDM.
No animal or vegetable fats or oils may be used with EPDM. This is because EPDM swells extremely with this type of medium and soaks up like a sponge.
With silicone, care must be taken not to use silicone grease. (like with like is not compatible)
Otherwise, the assembly grease can be freely selected for all other materials listed.
