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Hi, I am new to these forums and recently retired from the lubricants industry and now enjoying my new hobby of messing about with watches etc! I see a lot of posts on all forums about lubricants and thought I may be able to help with the basics so giving members a better understanding. This is a very broad subject so I will try and cover in a series of posts relating to specific areas of lubrication. I will try and answer any questions but may defer if I will be covering them in a later post. Firstly 'What are the different types of lubricants?' We have fluids (oils), semi-solids (greases and gels); solids Oils can be mineral (hydrocarbon), vegetable, and animal. Other fluids are generally classed as chemicals or synthasised fluids. Mineral oils are most common nowadays for lubrication but in the past vegetable (olive oil, rapeseed oil etc) and animal (lard, sperm oil, neats foot oil etc) were widely used. Some vegetable and animal oils are still used in mineral oil blends, especially neats foot oil, to provide special properties such as added lubricity. Refined mineral oils are made from crude oil, the refining process removes many of the 'nasties' to give a range of 'base oils' . These base oils have an industry range of viscosities and are used as made or blended together to meet industry standard viscosity bands (ISO VG). To meet specific lubrications needs (hot, cold, high wear, EP, water ingress, cleaning etc etc) chemical and other additives are blended into the basic mineral oil. Sometimes additives are needed to counteract the effect of some of these additives !!). Synthetic Oils can be based on mineral oil or be chemical compounds. Strictly speaking synthetic mineral oils should be called synthesised mineral oil as they are made by re-combining hydrocarbon molecules to make bespoke mineral oils. These are much purer and have better inherent temp, lubricity and oxidation properties, they also need less additives to modify their shortcoming properties. Ordinary mineral oil has molecule chains (her comes the chemistry!!), short, medium and long. The shorter the molecule the more volatile (will evaporate quicker) and lower viscosity (thickness, runniness) it has. The long molecules leave sticky, gummy residues when aged. The additives help to reduce these effects but they will all happen in time, and so the oil 'goes off'. Loss of short molecules can lead to oil viscosity increases and degeneration of the long molecules can lead to oil tickening and gums forming. Synthetic mineral oils can be made to greatly reduce the amount of small and large molecules (called light and heavy ends), so a more stable oil results. Also the natural contaminents of a natural mineral oils (which require additives to control them) are not present. Synthetic Oils based on chemical compounds are also used as specialist lubricants because of their unique properties, but are unlikely to be used in watches etc, but may be used as an additive for very special applications. They can also be very aggressive to some materials especially rubbers, plastics and paints. I'll post about additives etc in another post. Greases can be thought of as a lubricant retained in a sponge. The sponge is what is know as the 'soap' and the lubricant can be any of the above 'oils' that are compatible with the soap. The soap type is again determined by the operating conditions and the degree of specialisation required. Modern trends are to replace soaps with gelling agents but these have a more limited scope of operating conditions. Solid lubricants are materials that generally plate-out onto the working surfaces and can be applied as they are or suspended in a fluid lubricant. Typical solid lubricants are graphite, molybdenum disulphide, PTFE etc. They can cause problems in very tight clearances as they may tend to close them up over time. That's it for now, plenty to ponder on. Hope I haven't bored you too much. I will carry on with more posts if feed back is posiitive.