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I can verify Corey's experience regarding the #3M mag film issue (which 3M was aware, and worked hard to rectify). A real nightmare, as it would tend to "hang" when going over the heads, causing all kind of disturbances in the Davis tight-loop on the recorders/dubbers. --Scott Smith Chicago Audio Works, Inc. On 12/20/2015 1:15 PM, Corey Bailey wrote: > I only have anecdotal evidence that Charlie Richardson's suspicions > may be correct and it comes from the world of magnetic film: > > The vast majority of magnetic film, as we all know, was a tri-acetate > base product and thus suffers from vinegar syndrome (VS) over time. > However, one of 3M's last offerings was a polyester base, back coated > product that yes, has the tendency to go SS. I have encountered the > problem more than once with that particular type of mag film and all > of it has been stored in the best of conditions. Other manufacturers > offered polyester base magnetic film stocks that were not back coated > and do not tend to go SS. > > Holiday Cheers! > > Corey > Corey Bailey Audio Engineering > > > On 12/20/2015 5:24 AM, Tom Fine wrote: >> I should also mention, Charlie wanted me to send the tape back after >> the first transfer for "further processing." I decided, no, I want to >> see how it holds up in the real (reel) world, over time, under >> non-vault storage conditions. >> >> -- Tom Fine >> >> ----- Original Message ----- From: "Jamie Howarth" >> <[log in to unmask]> >> To: <[log in to unmask]> >> Sent: Saturday, December 19, 2015 10:54 PM >> Subject: Re: [ARSCLIST] One more sticky-shed data point - Richardson >> treated tape >> >> >> Very cool. Rad, scary, but if it holds up that's great. >> >> Please pardon the mispellings and occassional insane word >> substitution I'm on an iPhone >> >>> On Dec 19, 2015, at 8:54 PM, Tom Fine <[log in to unmask]> >>> wrote: >>> >>> Back in early 2014, I sent Charlie Richardson an old Ampex 7.5IPS >>> alignment tape, which is on Ampex 406 tape, circa 1970. The tape was >>> definitely sticky-shed, in fact the first couple of layers I wound >>> out by hand pulled oxide to the adjoining backing layer. Richardson >>> treated the tape with his "Rezorex" process, which apparently uses a >>> chemical peel to remove the back-coat layer, which Richardson >>> contends is the source point of sticky-shed. I transferred the tape >>> in May 2014 with no problems, then put it on a shelf in ambient >>> metro-NYC indoor environment. That first playback was on an Ampex >>> AG-440B. I just rewound and played the tape again, this time on an >>> Ampex 352. Still no sticky-shed evidence, and the audio was fine >>> (test tones were 10dB below reference tone, for the most part, >>> azimuth tones allowed stable adjustment). Richardson had left a >>> little bit of the end of the reel with the back-coat still on, and >>> that tape was solidly sticky-shed. I will keep on playing this tape >>> once a year to see if it goes sticky again. >>> >>> I think a more scientific test of this process would require >>> sacrifice of both a sticky-shed test tape and a high-fidelity music >>> recording on sticky-shed tape. Although Richardson wants tapes not >>> to have been previously baked and played, which he contends damages >>> the tape, I'd want a reference transfer after one bake. Then let the >>> back-coat layer be removed, and do a transfer with the exact same >>> equipment and compare both measurements and careful listening, see >>> if the chemical peel does any sonic damage. In the case of my old >>> test tape, all I'm saying is that the tones are at the announced >>> levels, and this tape could be used in a pinch to align a tape deck, >>> although I'd want to bet on a modern MRL tape if it were for >>> anything critical. >>> >>> One other thing. The tape with the backcoat removed is not as thin >>> as I thought it would be. It seems to move through the transport >>> just fine. I didn't observe any obvious edge-curl or country-lane >>> motion, and it fast-winds just fine through all the static guides on >>> an older Ampex transport. >>> >>> I'd want to do more testing with very familiar high-fidelity music >>> recordings to make sure the process doesn't do any damage to audio, >>> but for at least a year and a half, it does seem to prevent a return >>> of sticky-shed's mechanical symptoms. >>> >>> -- Tom Fine >> >