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1. Definition and role

Greases are lubricants with a semi-solid or paste-like consistency. They differ from oils in their much higher viscosity, which gives them better retention in place. In watchmaking, they are applied to contact points subject to significant pressure, slow movements, or on surfaces where a fluid lubricant would migrate too quickly. Their role is twofold: reducing friction between two metal parts in contact, and protecting these surfaces against wear and corrosion. Unlike oils, greases do not require a reservoir to be retained. They naturally adhere to surfaces and remain in place durably, even under the effect of vibrations and shocks inherent to wearing a watch.

2. Composition and properties

A watchmaking grease consists of three main elements: a base oil, a thickener and, optionally, additives. The base oil, mineral, synthetic or silicone-based, provides the lubricating power. The thickener — often a metallic soap or an organic compound — gives the grease its characteristic consistency. Additives improve certain properties: pressure resistance, corrosion protection or thermal stability. The consistency of a grease is measured according to the NLGI scale (National Lubricating Grease Institute) and ranges from very soft (grade 0) to very hard (grade 6). In watchmaking, grades from 0 to 2 are mainly used. Thixotropy — the property of certain greases to become fluid under mechanical stress and then regain their consistency at rest — is particularly appreciated for its ability to adapt to the demands of the Movement.

3. Natural greases (Moebius series 8 200 and 8300)

Moebius is a world-renowned and almost unique reference supplier of lubricants for watchmaking. Its range of natural greases covers a wide array of applications.

The series 8200 groups semi-liquid thixotropic greases with a natural base, intended for large-surface friction, slow-moving parts, and ball bearings. The 8200 is the basic, fusible, and versatile reference. The 8201 adds molybdenum disulfide (MoS₂) to enhance lubricating power under high pressure. The 8207 incorporates graphite for this purpose. These greases are particularly suited to areas subject to moderate loads and slow movements.

The 8300 series is intended for more demanding applications in terms of retention. The 8300 is a hard grease, recommended for springs and functions of the Winding mechanism. The 8301 (with graphite) and the 8302 (with MoS₂) are reinforced variants for steel-steel contacts under high pressure.

4. Barrel greases (series 8 200 — braking greases)

The Barrel is a special case: the grease acts as a controlled braking agent between the drum wall and the spring, regulating the winding of the Mainspring. The nature of the Barrel Material determines the choice of Lubricant.

The 8212 (Glissalube B, red) is a soft grease providing moderate braking, particularly recommended for Aluminium Barrel walls. Its colorless version, 8212-SC, is used when the red tint would pose an aesthetic issue. The 8213, a hard, orange-colored grease, provides more effective braking and is recommended for brass barrels. The 8217 (Glissalube 20) is a very soft braking grease, suitable for any type of barrel. The synthetic grease 9500, based on polyol ester, was specifically developed for lubricating modern barrels, with excellent stability.

It should be noted that modern mainsprings are self-lubricating and that adding grease would damage them. Only the walls of the barrel drums of automatic movements require such lubrication.

5. Synthetic greases (Moebius series 9 400–9550)

Synthetic greases offer superior stability compared to natural greases, particularly in terms of ageing and resistance to Temperature variations. They now form the basis for lubrication of modern Movements.

The 9415 is a thixotropic, soft, 100% synthetic Grease, specially developed for lubrication of the Escapement. Its excellent lubricating power and stability make it the reference for contacts between the Pallet stone and the Escape wheel. The 9501 is a slightly thixotropic soft Grease, developed for Steel-Steel friction in time-setting and other medium-load functions. The 9504, more versatile, suitable for a wide range of applications: Winding mechanism, calendar, time-setting friction. The 9550 offers great stability under compression, even at the highest pressures.

6. Silicone greases (Moebius series 8 500) and thixosilane

Silicone greases stand out for their exceptional chemical inertia. They resist water, UV, and oxidative attacks, making them essential for Water resistance applications.

The 8513 is a hard silicone grease, used mainly for the Water resistance of crowns, pushers and gaskets. The 8516 is the soft version, more suited to O-rings requiring gentle compression. Neither should be used for mechanical lubrication of Movement parts, as this risks degrading certain Materials incompatible with silicones.

The 9600-B (Thixosilane) is a special case: this thixotropic silicone-based fluid gel lies between Grease and liquid. It is used for low pressures, assembly, or press-fitting of fragile parts, where a soft texture is required without the risk of contamination by an overly fluid Lubricant.

7. Choosing the Lubricant and best practices

Choosing the appropriate Grease is as critical as the application technique. As a general rule, Grease should be applied in a minimal but sufficient amount: an excess attracts dust and can migrate to other parts of the component or Movement. Natural greases age faster than synthetic greases and warrant maintenance of the movement more frequent.