[ARSCLIST] Best practice: mixed acetate and polyester reels with sticky shed

[Goran Finnberg <mastering@xxxxxxxxx>]

Eric Jacobs:

> I have Scotch 201 (acetate base) and Scotch 206 (polyester base,
> back coated) in two dozen alternating segments.  The Scotch 206
> is very sticky.

But is it really sticky shed?

I have over 500 reels of Scotch 207, LP version of 206, and all reels play
as new with almost zero shedding of any sort.

Goes for several hundred reels of 206 that has passed by over the years too.

The technical crew at 3M, Bill Lund & Del Eilers, swears by their opinon
that the back-coated 206/207 family cannot under any circumstance be
affected by Sticky Shed as we know it.

Bill Lund:

Subject: [AMPEX] Re: ampex-digest V7 #328 - Baking Tapes
Date: Sat, 18 Sep 2004 16:51:51 -0500
From: "William F. Lund" <wflund@xxxxxxx>
Reply-To:ampex@xxxxxxxxxxxxx
Organization: Digital on Location
To: ampex@xxxxxxxxxxxxx
References: 1

To all:

To say again what I have mentioned several times over the past couple of
years. Baking tape is a process whereby you bring one of the chemical
components of the magnetic dispersion up to a high enough temperature to
cause it to melt and slowly soak back into the dispersion (magnetic
coating) where it will tend to remain for quite sometime. It probably
wont help much to put it into a bag with desiccant. If you heat the tape
to about 130 degrees and leave it there for about 12 hours and (most
importantly) allow it to return to room temperature VERY slowly (about
another 12 hours) you will find that the tape will remain playable for
years to come. In fact, little difference (if any) will be noticed
between baked and new tape.

The key is to NOT be in a hurry. Do not be afraid to leave the tapes in
the oven for 12 hours or more and do not be in a hurry to bring them to
room temperature. Allow at least 24 hours for the entire process, you
will be glad you did.

3M tapes of the 226 family (226,227,806,807,808,809) responded perfectly
to this process, none of the others ever exhibited sticky shed. The
other thing to remember is if you hurry the process and they become
sticky again, you didn't a)get them to a high enough temperature,
b)didn't leave them in there long enough or c)tried to do the process
too quickly.

Remember, plastic reels will hold their shapes until about 160 degrees F,
metal reels are never a problem.

Good Luck

Bill
3M tech service (ret)

Bill Lund of 3M wrote on 3 may 2001:

In 3M's case the 226 family (226,227,806,807,808,809) were the ONLY tapes to
exhibit 'binder breakdown'. No other 3M tape ever exhibited that problem.
The 226 
family was the only tape ever to use that oxide and chemistry. The 900
series of 
3M tapes (996,997,986,987,908,909) was specifically developed to get away
from 
the binder breakdown problem.

They  used completely different oxides from different companies and totally
revised 
binder chemistries.

----------

BTW, I don´t deny what you have seen, Eric, I just wonder if it is truly
sticky shed?

The gist of the Del Eiler & Bill Lund message is coming from the fact that
if you know the ingredients that makes up a certain magnetic tape family
then one can very accurately predict if it will go sticky shed in the
future.

And the 206/7 family is not one of them according to the chemists at 3M lab.


-- 

Best regards,

Goran Finnberg
The Mastering Room AB
Goteborg
Sweden

E-mail: mastering@xxxxxxxxx

Learn from the mistakes of others, you can never live long enough to
make them all yourself.    -   John Luther