Why Steam Cylinder Oil?

One of the things I did on vacation was to visit a maritime museum. My interest was focused on the large steam engines over 1000 horsepower which are still operational. Steam Cylinder Oil is an ingredient in many old bullet lubricant recipes. It would not have been used repeatedly by many knowledgeable shooters if there was not some tangible benefit.  Unfortunately Steam Cylinder Oil is no longer available, so WHAT are people using when running steam engines today, and why a special oil? The steam cylinder in a steam engine is different your car's cylinders because it is constantly bathed in hot water and steam. The hot water has a much higher affinity for the metal surfaces in the steam cylinder than any petroleum oil or grease. Normal petroleum lubricants are quickly washed off, causing the piston and cylinder to wear out. Experience in the 1800's showed animal lubricants ”€œ tallow of various types worked well. In fact Steam Cylinder Oil is sometimes referred to as Tallow Oil in old books. So what is being used in current steam engines? Tallow, no surprise there, it is even solid in the lube cups but liquefies when the engine is running. Canola oil is also used, it is easy to find at the local grocery and has no salt which sometimes contaminates tallow. It turns out during WWI there were a lot of steam engines in ships. Tallow was in short supply because it was used to make explosives. A search was made for a replacement. Rape seed oil was found to work nicely. Rape seed oil is canola oil, just a different name. Modern canola is a bit different and I expect a lot cleaner than the old lubricant oil, but canola should be a good replacement if you want to try some of the historic lubes in Ralph Schneider's list which worked well for many shooters. The polar component effect. The difference in lubricants in steam engines is because of the polarity of the lubricants. The lubricants used in the other bearings in steam engines are normal petroleum lubricants. Most operators today use modern lithium greases, some with added molybdenum disulfide. Lithium greases are more polar than straight petroleum grease, but not enough to use in the steam cylinder. Water is very polar, what is needed is a polar lubricant with more affinity for metal than water. Why is this important? We are not using steam powered guns, but what we do want is a bullet lubricant with high affinity for the steel barrel which will prevent the lead from adhering to the steel and spoiling accuracy. Polarity is perhaps the most important physical property in bullet lubricants. ALOX 50/50 is still one of the best lubricants, it is a mixture of beeswax (polar) and ALOX 2138F (polar). Attempts to replace the expensive beeswax with cheaper microcrystalline wax (non-polar), gave poorer lubricants which were not commercially successful. Some commercial cast bullets are lubricated with colored microcrystalline wax. Microcrystalline wax is available in arrange of hardness form very soft to very hard and a wide range of melting points. Usually a hard high melting point variety is used to allow shipping in a bulk box. This lubricant is adequate for light pistol and revolver loads at 800 fps, perhaps up to 1000 fps if gun/bullet fit is perfect. Use in magnum revolvers or rifles can be disappointing, leading builds up and accuracy goes down. A coating with any of the liquid ALOX lubes adds a polar lubricant and makes the bullets useable at higher velocity.      Petroleum products like Vaseline, Ceresin paraffin and microcrystalline wax, have no oxygen and are non-polar. Organic oils and organic waxes are polar because oxygen is part of the molecular structure. ALOX compounds are produced by controlled oxidation of petroleum at high temperatures which forms oxygen containing compounds which are polar. Some homemade lubricants include a “cooking” step where the lube is stirred at high temperature for a long time, this causes partial oxidation, forming polar compounds. If you want to experiment with bullet lubricants you need to pay attention to polarity. Fortunately the internet has made chemical structures easy to find.  Look for the big O in the structure, you might be onto the next great lube. Steve Hurst