Machinery Lubrication magazine published by Noria Corporation
Issue link: https://www.e-digitaleditions.com/i/778560
By Mark a. TarBeT, LuMinanT Power INDUSTRY FOCUS L u b r i c a t i o n P r o g r a m s 14 | January - February 2017 | www.machinerylubrication.com Grease compatibility charts have been developed and circulated since the 1980s without much alteration. However, grease technology has changed significantly over the years, and there are many examples of performance that contradict several widely used compatibility charts. This article will describe the most common examples of incompatible grease mixing and how to determine if two greases are compatible. Examining Compatibility Charts A number of organizations rely on compat- ibility charts to make important maintenance decisions. These charts are readily available in published papers, periodicals and Web pages. Unfortunately, very few charts give any refer- ence for the origin of the data or any research utilized to establish the compatibility rela- tionships described. Significant concerns have also been raised about some of these charts after greases presented as compatible have proven to be quite incompatible. A selection of 17 compatibility charts was recently evaluated for differences. The chart on pages 16-17 shows the labels used in these charts and how many times these descriptions appear in the charts. Seventeen occurrences would indicate that a grease category was present in each of the charts found, and there were only three such products. The three products that appeared in each of the tables were aluminum complex, lithium complex and calcium complex. However, the commonality ends there. A total of 25 different product descriptions were found in the 17 tables. Some may have been referring to the same product categories but failed to use common nomenclature, so it is difficult to determine where there might be an overlap. Contradictions Several contradictions were discovered among the various charts. For example, one chart indicated that barium-complex grease is compatible with clay-thickened grease, while others suggested this mixture is incom- patible. Some charts listed polyurea grease as being compatible or borderline compatible with calcium complex, but another chart GREASES How to Determine Important Grease Compatibility By ricHard n. WurzBacH, MrG l aBs Why It's and