Passivated Per QQ-P-35C,type 11 Passivated Per QQ-P-35C,type 11 daxmann (Aerospace) (OP) 26 Oct 15 13:22 Does anyone know the difference between Passivate Per QQ-P-35C,type 11 and Passivate Per QQ-P-35,type 11. I don't have access to the specs but I'm sure the differences must be small. Thank you. RE: Passivated Per QQ-P-35C,type 11 monkeydog (Aerospace) 26 Oct 15 21:02 I will assume you know that QQ-P-35C is Cancelled QQ-P-35C does not have Type 11.I, or Type 11, but does have Type II but no II.I or II.1. QQ-P-35C was superseded by AMS-QQ-P-35A, but alas, AMS-QQ-P-35A has been cancelled, and superseded by AMS2700E, that also does not have a Type 11 or Type II, but does have Type 2. In AMS-QQ-P-35A, if you wanted to use Type II, you now need to call-out AMS2700E Type 2. In AMS2700 you can use Method 1 which is passivation in Nitric Acid, or Method 2 which is passivation in Citric Acid. RE: Passivated Per QQ-P-35C,type 11 daxmann (Aerospace) (OP) 27 Oct 15 11:37 Thank you for all the information monkeydog. It looks like I'm behind on all the cancellations. I'll get things updated. Thanks again. RE: Passivated Per QQ-P-35C,type 11 WKTaylor (Aeronautics) 27 Oct 15 22:05 daxmann... QQ-P-35 original [rev 'new'] Specifies Types I, II and III [low temp, medium temp and high acid bath temperatures, respectively]. QQ-P-35 rev B Type I - Low temperature, Type II - Medium temperature, Type III - High temperature, IV - For steels containing large amounts (0.15 percent) of sulfur or selenium, Type V Anodic - For high carbon martensitic (IE 44O) steels and Type VI - an Low temperature (solution). QQ-P-35 rev C revised the 'gene-pool' one more time: eliminated types I, III, IV, V and added VII medium temperature nitric acid and type VIII medium temperature high-concentration nitric acid solution. Generally speaking, I heavily endorse AMS2700 Method 2 which uses citric acid and is relatively free of danger associated with heated nitric acid baths. NOTE. As a 'field expedient', I sometimes recommend applying Pasa-Jell 101 per USAF T.O. 1-1-691, in-lieu of typical passivation treatments that are simply not available in the bare base environment. Regards, Wil Taylor o Trust - But Verify! o We believe to be true what we prefer to be true. o For those who believe, no proof is required; for those who cannot believe, no proof is possible. o Unfortunately, in science what You 'believe' is irrelevant. ["Orion"] o Learn the rules like a pro, so you can break them like an artist. [Picasso] RE: Passivated Per QQ-P-35C,type 11 tbuelna (Aerospace) 28 Oct 15 03:18 daxmann- you can find an old copy of QQ-P-35C here. But as others noted this spec has been cancelled. Can you tell us the reason you are using this spec for passivation? Does your application involve some legacy hardware that calls out this process? This is a common situation and there are actually still a few vendors that work to this spec. RE: Passivated Per QQ-P-35C,type 11 daxmann (Aerospace) (OP) 28 Oct 15 11:40 The parts are proprietary but I can say there is some legacy hardware. Thanks for all the information guys.