Moebius 8217 silicone grease is the reference lubricant for watch gaskets: case-back gasket, crown gasket, crystal gasket, pusher O-ring. A thin film prolongs the life of NBR, FKM/Viton and EPDM gaskets, preserves their elasticity and ensures the long-term water resistance of dive and dress watches alike.
Product overview
The 8217 is a high-purity silicone grease developed by Moebius (Switzerland) for watchmakers. Compatible with all elastomer families used in modern watch construction (NBR, FKM, EPDM, Hytrel), it does not swell rubber, does not migrate into the movement and remains stable from −40 °C to +200 °C. It is the lubricant recommended by Rolex, Omega and Seiko for gasket service.
Technical specifications
- Brand: Moebius (Switzerland)
- Reference: 8217
- Composition: pure silicone grease
- Compatibility: NBR, FKM/Viton, EPDM, Hytrel
- Temperature range: −40 °C to +200 °C
- Container: 2 g or 5 g pot
- Shelf life: 5 years sealed
- Origin: Switzerland
When to use it
Apply 8217 to every gasket changed during a service. A thin film on the case-back gasket guarantees water resistance up to the rated ATM. A drop on the crown gasket extends the life of the threaded stem. A film on the crystal gasket prevents micro-leaks under pressure.
How to install / how to use
Open the pot in a clean area to avoid contamination. Use a wooden peg or a clean cotton bud to pick up the grease.
- Remove the old gasket from the case.
- Clean the gasket seat with isopropyl alcohol.
- Inspect the new gasket for surface defects.
- Pick up a small amount of 8217 on a wooden peg.
- Apply a thin, uniform film around the entire O-ring.
- Seat the gasket in its groove without twisting.
- Close the case and pressure-test the watch.
Materials and compatibility
Watch gaskets exist in several elastomer families, each with its own properties. NBR (nitrile butadiene rubber) is the most common and offers good resistance to oils and ageing. FKM (also marketed as Viton) withstands higher temperatures and aggressive solvents, and is the preferred choice for professional dive watches. EPDM resists ozone and weathering and is often found on sport models. Hytrel, a thermoplastic elastomer, is used on certain Rolex and Omega references. This tool is fully compatible with all four families, provided the gasket is lubricated with a silicone grease such as Moebius 8217.
It can be safely used on Swiss makes (Rolex Submariner, Omega Seamaster, Tissot PRX, Longines HydroConquest), Japanese makes (Seiko 5, Seiko Prospex, Citizen Promaster) and German makes (Sinn, Junghans) as long as the case-back type matches the tool's purpose. For watches rated above 10 ATM, always pressure-test after every gasket service.
Maintenance and storage
Keep the tool dry, in a clean drawer or its original sleeve. Wipe the metallic parts with a soft cloth after each use; if you have worked near solvents, dry the steel parts immediately to prevent corrosion. Inspect the working surface (tip, head or die) for marks or burrs every few months; small irregularities can be polished gently with a fine-grit abrasive cloth, but heavier damage requires replacement.
Avoid contact with strong acids, chlorinated cleaners and rubbing alcohol on plastic handles. Heat above 60 °C can soften polymer grips and reduce dimensional accuracy on precision blades — never leave the tool in direct sunlight or near a soldering iron.
Common mistakes to avoid
Three errors account for the majority of damage observed in workshops: applying excessive torque (which strips the case-back notches), using the wrong tip diameter (which slips and scratches the bezel), and forgetting to replace a hardened gasket after service (which compromises water resistance even with a fresh O-ring of the wrong size). Always work under a loupe, double-check the gasket reference before ordering a replacement, and verify the seating of the case-back before closing the watch.
A final tip from the workshop: never combine a new gasket with an old, dried-out one on a multi-seal case. If the case-back gasket is replaced, also inspect the crown gasket and the crystal gasket — they age at the same rate and a single tired O-ring will let humidity in.
Quality and origin
Moebius is the historical Swiss reference in horological lubrication. The 8217 is produced in Le Locle under strict quality control.
Frequently asked questions
Can I use it on a Rolex Oyster gasket?
Yes, the 8217 is the silicone grease specified by Rolex service centres for case-back and crown gaskets.
Is it compatible with Viton?
Yes, the 8217 is fully compatible with FKM/Viton, NBR and EPDM.
How long does a 2 g pot last?
A single pot covers several hundred services thanks to the very small quantity applied per gasket.
