I would like to know how to check whether a certain lube oil (unused) contains wear metals. Is there any other simple and easy way to check other than taking it for analysis?
Someone told me I can put a few drops of oil (e.g. used oil) on paper and the way it spread over paper is different from if I used unused oil. How reliable is it and how do we explain it?
If i have to do wear metal analysis, what method should i use?

I forgot to say that I wanted to test wear metals on unused lube oil. I actually wanted to check whether the oil contain used (recycled)oil or not. How do i check? Thanks.

Metallurgy chemistry of machinery components is different than the chemistry of basestocks and additives in particular. So AES (either ICP or RDE)would be an ideal option for identifying used oils in unused oils. In addition, as the molecular chemistry of used oils has undergone some changes, so FTIR spectroscopy can be another alternative to check if there is any used oil in the unused one.

I was told to use astm D5185. but is there any other method?

Hi Hazel,
To check for wear metals then you would run spectroscopy analysis. It really doesn't matter which one unless you are overly concerned with ppm accuracy. Or if you really want to do this at home then clean a magnet and put it into the oil. You might want to consider wrapping it in plastic. (Most common wear matals are Fe based) So then you look at the magnet/plastic bag under a microscope. Even in a new oil from a reputal manufacturer supplier there might be small amounts of "wear" metals.
Comparing a new oil to a new oil you suspect is mixed with used oil by comparing the colour that is left on a blotter paper will be inconclusive. The manufacturer can change the source of supply of their base stock and it might be a slightly different colour than the origional. How would you know which was which?
FTIR as lish suggested could be used but only if you are comparing, through spectrial subtraction, the analysis from the same batch of base oil, then you could compare the commonly known frequency bands for oxidation etc. The bad part here again is that the oil could have been stored in a high temperature environment.
All this boils down to the fact that if the oil is re-refined then you will in all likelyhood never know (unless the manufacturer has claimed the tax benifets avaliable and has it printed on their label)

So testing it at home or testing it in the lab unless it is grossly obvious that it is a used product, you will not be able to determine the difference.

regards.....

Hazel,
As Alan just said, you allways will need lab test. An even having it will be pretty dificult to identify one from the other.
If you can provide more information to the forum about what especific type of oil, maybe could help to give you more options.

Hi Hazel
as Alan has suggested that to run a magnet is a coarse way of testing metal particle in unused sample of oil, but again sampling needs to be done rightly fo this.
Second is to put a representative sample on a blotter paper and look for shiny metal particle undera microscope for non magnetic wea particle.
These test can be done with some test kits in the plant.
Other wise its Spectrography and FTIR for additive depelation and they are costly and needs to send it to lab who has them.
regards