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Sorry, I was quoting from memory and not the 3M product sheets. Thanks for the correction. Corey At 03:46 AM 12/18/2009, you wrote: >Corey: > >This history is wrong about Scotch formulations. > >Scotch released 206, 207 and 208 in the late 1960's. Around the same >time, Ampex released the original formula of 406 and 407. I can tell >you for a fact that 206, 207 and 208 (which was designed for low >print-through and low noise for sound-for-picture work) were around >before 1970, I have reels dated 1968 and 1969. > >As I understand the sticky-shed story, at some point in the 1970s, I >think the early 1970s, Ampex changed some ingredient in their binder >"stew" and this was the root cause of the problem. It effect 406/407 >from that point onward and also effected the later Grand Master >456/457 line. Richard or someone else can say for fact whether it >effected more advance Ampex formulations like GP9. At 3M, the >chemistry was not changed for 206/207/208 but the new 226/227 that >was introduced in the late 70's or early 80's had the same >sticky-shed problems as Ampex tapes. Also 250, I think. Also the >formula that 3M came out with for Nagra location-sound recorders, I think. > >After the sticky-shed problem was discovered and baking was deemed a >suitable solution to play a sticky tape, Quantegy (the former Ampex >tape division) supposedly changed the formula of all their >back-coated tapes to prevent sticky-shed. There are varying reports >whether this is true. I have 406, 456 and 457 stock from as far back >as 1998-99 timeframe that has not gotten sticky so far, but others >report other results. 3M exited the tape business in the 1990's, so >their formulations with problems were never changed. > >Somewhere online used to be an annotated history of 3M formulations. > >-- Tom Fine > > >----- Original Message ----- From: "Corey Bailey" <[log in to unmask]> >To: <[log in to unmask]> >Sent: Friday, December 18, 2009 1:40 AM >Subject: Re: [ARSCLIST] Tape Squeal > > >>Hi Shai, >> >>Scotch 206 was 1.5 mil polyester, back coated and the top of the 3M >>line until >>the introduction of 250. 207 was the 1 mil version of 206 and, as far as I >>know, was the same formulation. During the 80's, 3M released Scotch >>208, aimed >>for the feature film production sound community claiming it was as >>reliable as >>206. I till have some 208 from that era. I should check it out. >> >>"If it ain't Scotch 206, Bake it!" was somewhat of a >>tongue-in-cheek statement. >>However, of all the formulations that were produced, 206 seems to >>have been the >>most stable over the years. This doesn't mean that it should not or cannot be >>baked, but I am comfortable with playing it before making that decision. >> >>Cheers! >> >>Corey Bailey >>Corey Bailey Audio Engineering >> >> >>Quoting Shai Drori <[log in to unmask]>: >> >>>Please continue this discussion on list. I have also found that baking >>>most tapes helps them run on the machine. Don't have much experience >>>with 206 so I must ask why should this be excluded? Is it the standard >>>length version of the 207. I had a couple of these that were back >>>coated. The emulsion just came off the tape one day. I tried Last's >>>product for vinyl and was very disappointed. What product did you use? >>>Maybe different products produce different results. I'm still waiting >>>to see photos from Marie's mods. >>>Shai