For many years (60s-70s) i worked with DAK( the catalogue electronic guru) and
we re-slit 10's of 1000's of reels of computer and instrumentation tape from 3M,
Ampex (main frame computer tape) Sound craft (brown oxide).
Having access to all this stock i was always bringing rough winds or short
reels home....... to which i still have an outside storage shed full of 7/10"
x1/4 and 10x1/2 inch tape. Stored with out regard for heat and cold.
I pulled some of this stock since this sss discussion and the 3M instrumentation
stock from the 60-70 doesnt seem to show any sss. The same goes for Ampex 1/2"
computer even the backcoated.
I would think that the binder would be the same for
audio/computer/instrumentation/video tape coating lines would be the same
....... it would be the oxide formulation or grain orientation that would be
Any comments ?
----- Original Message ----
From: Richard L. Hess <[log in to unmask]>
To: [log in to unmask]
Sent: Wed, December 22, 2010 2:39:15 PM
Subject: Re: [ARSCLIST] SSS and other failure modes (was if you want it done
right, do it yourself .../ not always)
Hi, Shai and Michael (and Michael from off-list),
I am here wrapping Christmas presents for my family...and figuring how to deal
with 17 microphones (9 wireless) for the church Christmas Pageant Friday
afternoon at the 3 and 5 PM services.
Anyway, this is a complex issue and is addressed to some degree in my paper from
the ARSC Journal.
My paper on tape degradation that was originally presented at the Audio
Engineering Society's 121st convention in October 2006 in San Francisco was
published in the ARSC Journal in the Fall of 2008. It is available here:
However, this discussion is equating SSS with back coating.
What I think I know is:
(a) Almost all SSS tapes also have back coating.
(b) Not all back-coated tapes exhibit SSS.
(c) Charlie Richardson claims that removing the back coating will restore the
tapes. He can discuss his findings in greater detail. I can't speak for him or
his patented process which I have never tried to replicate.
(d) The chemistries of the mag coat and the back coat may be similar or
different, depending on the tape.
(e) The precise chemical makeup of the tapes is unknowable at this point.
(f) The degradation trajectory relating to basic chemistry, out-of-control
processes (i.e. out of spec tape) and storage conditions is impossible to know
at this point.
(g) It appears that at least some manufacturers of some tape types substantially
changed the tape chemistries while maintaining the same "model number". This is
best documented by Benoit Thiebaut in his testing of video cassettes for Presto
(h) We think that polyester polyurethane binders were introduced about the same
time back coating was introduced, so there may be no cause-and-effect
(i) Some archives (I believe Screensound Australia) interleaves paper leader
with back-coated tapes so that the back coat and mag coat are not in direct
(j) While the analogy may fail, have you ever seen an electrostatic copy (like a
Xerox) that has spent a long time in direct contact with a vinyl binder? It's
enough to make one wonder, at least.
(k) Some polyester-polyurethane compounds do a good job of breaking down when
exposed to moisture, especially at elevated temperatures.
(l) Bradshaw did enough work to disprove that the chains re-link when baking as
it just doesn't happen in a filled matrix.
So, that's off the top of my head in five minutes...there is no simple answer
and I doubt we'll ever have something as easy to use as a "pool test kit" for
determining the likelihood of future SSS failure. If it says Ampex 406/407/456
on the box/reel and there is no reason to disbelieve it, bake before winding.
I was also asked off-list about the composition of the back coat and I suggest
the answer is really (e), above. Yes, carbon black is in many of the back coats
to drain off static, but the "bad actor" here is not the carbon black but rather
the binder chemistry. Also, I've never seen a back-coated audio CASSETTE tape.
I have some SM911 that is going bad--I'm not certain it's SSS or just shedding.
I forget if it's BASF or EMTEC.
Here is a list of degrading tapes that I _attempt_ to keep current.
I've been asked to do work on some Sony PR-150--pray for me.
On 2010-12-22 2:13 PM, Shai Drori wrote:
> It's a good argument, but has it been tested. Has anyone tried to store a back
>coated tape without it's back coating to see the difference? If I remember
>correctly (where is Rich Hess when you need him) the SSS was first discovered in
>ampex 400 series, but it was the new binder they used. I don't see how that is
>affected by the back coating, and why doesn't it affect all back coated tapes. I
>have many different tapes with back coating, some of them almost 30 years old by
>now that play like the day I bought them. Maxell XLI, BASF pem468, BASF dpr26,
>emtec 911 (not 30 years old). To put the blame on the back coating just because
>if is from the same era. It should have sown up in all back coated tapes. What
>am I missing?
> On 12/22/2010 8:47 PM, Michael Biel wrote:
>> On 12/22/2010 2:27 AM, Shai Drori wrote:
>>> I have many tape that are back coated that show no SSS. In my experience there
>>>is no connection whatsoever.
>> But how often have you found non-backcoated tapes with SSS?
>> Mike Biel [log in to unmask]
>>> On 12/22/2010 8:46 AM, Michael Biel wrote:
>>>> The one saving grace of 8mm is that I don't think I have come across a
>>>>backcoated tape in this format. So if there is any truth to SSS being a
>>>>reaction to backcoating, that reduces that problem.
>>>> Mike Biel [log in to unmask]
-- Richard L. Hess email: [log in to unmask]
Aurora, Ontario, Canada (905) 713 6733 1-877-TAPE-FIX
Quality tape transfers -- even from hard-to-play tapes.