| Mark me up as another of those who have had to switch from Al Cass to something else. I found A.C. was promoting a dark yellow 'varnish' color on (mainly) the 2nd valve piston of all four of my horns (flugel, cornet and 2 Bb, all horns of different makes and both monel and stainless valves). As soon as I went to a synthetic (initally Clark Viper Oil and laterly Zaja Blue...at Leigh's recommendation again) the problems disappeared... and after a year have not reappeared. Prior to that I was having to "scrub" the varnish off every two weeks!
Al Cass (and, to be fair, all other "oil"-based oils) can (according to one website I read) can combine with a particular person's body chemistry AND heat (as in "high temperatures") to form this coating. Still, Al Cass IS probably the most commonly sold oil out there but, like anything else, there are exceptions to the rule. |