When excess amounts of oil become aerosolized by the compressor’s discharge, it can be damaging to pneumatic tools and accessories. Even worse, oily discharge can cause ill effects on applications, sometimes to the point where projects must be scrapped and reworked entirely. Luckily, the problem is usually easy to identify and remedy, since oily discharge is typically due to one of the following issues:
- Restricted intake — Oily discharge is often caused by restrictions on the compressor’s air intake. In this case, the air filters should be cleaned or replaced.
- Worn out piston rings — Just as with oil leaks, oily discharge can stem from worn piston rings, which need to be replaced on a periodic basis.
- Overfilled oil tank — If the compressor has too much oil, some of that excess can seep into the discharge. Compressor oil should only be added to the “full” mark displayed on the gauge.
- Wrong oil type — Your air compressor requires a special type of oil to operate at maximum efficiency and prevent issues such as oil carryover as described above. If the wrong type of oil has been used, the machine should be drained and in some cases flushed prior to replacing with the correct oil type.
- Inverted piston rings — A further possible cause of oily discharge is if piston rings are installed upside down. In this case, all of the oil could be pumped out of the machine and cause catastrophic damage.
If you use compressed air for the purpose of spray painting, sanding or the application of finishes, you cannot allow aerosolized oil to enter the airstream. With preventative maintenance, you’ll greatly reduce the risk of having projects ruined by the interference of oil particulates in paint jobs and finishes.