Dear Greg, We have run into the same problem with some of our very early recordings and developed a means to deal with it, which may be of use to you;
The handling has been to bake the tapes under controlled conditions. This means using a stable temperature (approx 120 degrees) for many hours (at least 8 hours). The baking is done in a convection oven which circulates the heat evenly throughout the oven. The tape is then allowed to slowly cool over approximately the same time period as was used for baking it. The tape is then good for approximately a month, during which time it should be copied." I also have an article from 1997 which describes the phenomena and the procedures if you are interested.
From: Greg Schmitz [[log in to unmask]]
Sent: Monday, July 15, 2013 11:36 PM
To: [log in to unmask]
Subject: [ARSCLIST] Conservation question: oxide delamination and consolidation
At some point in the future the archive I work for may have to deal with
hundreds, perhaps thousands, of helical audio recordings made in Alaska
using Soundscriber SS-124s (helical recorders which capable of recording
24 hours on a 2 inch tape medium). When we conducted a brief and spotty
inspection a couple of years ago of the tapes, recorded in the early
1960s, now stored a warehouse without climate controls, we found that
many of the tapes showed signs of de-lamination; the oxide coating is
flaking off of the base of many tapes. I'm trying to get ahead of the
curve and was wondering if anybody here could point me to literature, or
offer advice, on consolidating magentic audio tape oxide coatings?
Thanks in advance.
Alaska Moving Image Preservation Association (AMIPA)
greg /at/ amipa.org
The Alaska Moving Image Preservation Association is a 501(c)(3) non-profit dedicated to media preservation and education to ensure long-term access to Alaska’s moving image heritage.