Your Step by Step Guide to Patch Testing

  • patch testing
  • How to guide

The very best oil analysis programs incorporate some degree of on-site analysis. For most plants, mills and mines, particle monitoring is the most productive onsite oil analysis activity available. A simple patch test enables the technician to quickly identify abnormal levels contamination and wear debris so that corrective actions can be scheduled accordingly.


1. In order to ensure accurate results, it is crucial to assemble and carry out tests in a suitable clean room if possible and never set up in the open or where atmospheric dusts/welding/grinding or maintenance work is being carried out.2. Use a clean working surface and if possible cover the area with wiper toweling or similar.3. Always use lint free wiper materials for cleaning purposes.NEXT STEPS1. Assemble the patch base funnel. 2. Using tweezers, carefully place a 47 mm filter membrane onto the screened surface of the funnel's neck, place the top measured 250ml fluid holder over the patch and secure with the hand clamp.3. Cover the assembly with the provided Petri dish

4. After aggressively agitating the sample, pour the oil into the funnel precisely to the 100ml mark5. Fill the funnel to the 150ml mark with the Evolve CH10/12 spirit dispensed through a filtered 0.8micron pressurised gun (60 psi) and re cover with the Petri dish to prevent air bourne contaminants entering the prepared sample6.Draw the diluted sample through the filter patch by activating the vacuum pump until the funnel is nearly empty7.Wash the sides of the measure glassware by using 10/20 ml of Evolve from the spray gun and wait 30 seconds for the mix to settle8.Draw the mineral spirits plus remaining oil through the filter by activating the vacuum pump until the funnel is empty9. Leave the pump running for approx 30 sec to dry the membrane and remove the top measure glass to allow the patch to dry using the vacuum pump for another 60 seconds or until the patch is visually dry10. Using the tweezers, remove the patch and place it into a prepared membrane holder slide11. Place the slide with the top removed under the microscope for examination


1. Using the microscope eyepiece focus and visually compare the debris on the slide using the supplied booklet look for the nearest ISO code guide to your patch and types of contaminants

2. A visual examination of a particle's morphology - its shape, size, colour and other details - can also be used just like conventional ferrography to help elucidate the source of any particle

3. Not down the results and save for future records

4. Microscope with cameras are supplied with software that allows the user to size individual contaminants on screen. This aids the reporting function for items such as warranty claims, supplier disputes etc.

For specification or pricing on our patch test kit, please do not hesitate to contact our technical team on 0115 9003600 or email