Scott D. Smith:

> On the other hand, I recently transferred some
> 1/4" and 1" reels of 3M 206 and 208, some of
> which was of fairly recent vintage, and all of the
> material exhibited problems with binder breakdown

I have never seen 206 or 208 exhibit binder breakdown thus have I never
needed to bake any of them.

I don´t doubt your experience as you are a seasoned professional.

However for what it is worth Bill Lund of 3M has stated many times on the
Ampex email list that under no circumstance, based on the chemistry
involved, will 206/207 nor 208 go sticky shed.

See the following email from Bill Lund:

Subject: [AMPEX] Re: ampex-digest V7 #328 - Baking Tapes
Date: Sat, 18 Sep 2004 16:51:51 -0500
From: "William F. Lund" <[log in to unmask]>
Reply-To:[log in to unmask]
Organization: Digital on Location
To: [log in to unmask]
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.

------------------------

My comment:

Bill Lund stated:

> The 226 family was the only tape ever to use that oxide and chemistry.

The 226 family has the same chemistry as Ampex 456.

Which as we all know is the worst ever for sticky shed together with Ampex
406/407.


--
Best regards,

Goran Finnberg
The Mastering Room AB
Goteborg
Sweden

E-mail: [log in to unmask]

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