XPost: alt.home.repair   
   From: kludge@panix.com   
      
   In article , mike   wrote:   
   >On 27-03-2021 17:01 Scott Dorsey  wrote:   
   >   
   >> Viscosity breakdown with time,   
   >> viscosity curve with temperature, adhesion, solvent characteristics,   
   >> ability to keep particulates in solution, three-ball test, etc.   
   >   
   >All oils "breakdown with time."   
      
   Yes, that's why you test it.  It's been forty years since I took tribo class,   
   but at the time there was a standard measurement with a rotating drum inside   
   a stationary drum that creates high shear on the test sample.  You measure   
   viscosity regularly and plot it against time.   
      
   Clean linear paraffin oils did well on the test, oils with a lot of   
   crosslinking or rings did poorly.   
      
   You'd think a "synthetic oil" base would be pure linear paraffin chains with a   
   very narrow range of molecular weights and you might be right or you might   
   be terribly wrong, depending.  Also, of course, the VI breaks down, not just   
   the base oil.   
   --scott   
      
   --   
   "C'est un Nagra. C'est suisse, et tres, tres precis."   
      
   --- SoupGate-Win32 v1.05   
    * Origin: you cannot sedate... all the things you hate (1:229/2)