3m—magnetic-media-maker, review.html

3M – Magnetic Media Maker, a history of the first four decades (1944...1985),

by Charles L Alden

Book Review by Jay McKnight and Bill Lund


The idea of magnetic recording dates from Oberlin Smith, in 1878, and was realized with wire recorders from Valdemar Poulson in 1898, but wire was too expensive, too heavy, and too hard to splice to be a real commercial success. Then in 1928 the Austrian inventor Fritz Pfleumer patented a paper tape coated with a magnetic material. German companies soon started developing and manufacturing magnetic tape and tape recorders, but it was not until the end of the war in the 1940s that the Allies learned of the progress that had been made in tape recording in Germany during that time.

In 1944, Otto Kornei of the Brush Development Company wrote to the Minnesota Mining and Manufacturing Co (“3M”) asking if they would be interested in developing a thin non-metallic tape coated with an emulsion containing a ferromagnetic powder. 3M said that they would like to try, and thus was born a major US industry.

In 1984, the 3M management asked 3M employee Charles L Alden to compile a history of 3M’s activities in magnetic recording tape invention and manufacturing. This was the first time that most of these ideas were revealed publicly. The result was a 134 page manuscript called “3M – Magnetic Media Maker”, that was completed in 1987. But management decided that they did not want to publish it, so it was shelved for about 17 years. Charles Alden died in 1989.

In 2004 a copy of an extract of this history found its way to my hands, and I passed it on to 3M retiree Del Eilers. He and his wife Karen were able to find the complete original manuscript and assemble it for publication. The book was finally published only months before Del's untimely death in 2014 December.

  Del's contribution to the Magnetic Tape Industry was huge. He was the best remaining 3M person to put the materials together

The book’s 25 chapters give the the history of 3M’s research, manufacturing, and selling of magnetic tape, starting with the original proposal based on 3M’s experience in producing precision coated tapes, and their known coating research capabilities. Of course 3M did not have, nor had it even seen, a “tape recorder”. They weren’t even sure if anybody would want “sound recording tape”.

By 1946 there were several companies making tape recorders, and anxious to have a supplier of recording tape. 3M developed or found vendors of magnetic materials, binders, base materials, coaters, and slitters. By 1947 June they shipped the first Nr. 100 paper-based “Scotch” Sound Recording Tape. Soon many companies were found that were anxious to record other signals – “data” – on magnetic tape.

The following chapters detail the struggles of developing improved coating materials, methods, and bases, and of selling tape into the expanding fields of sound recording, data recording, and instrumentation recording.

By 1956 Ampex had developed the first really practical Video Recorder, without revealing it to anyone outside of Ampex. And several tape manufacturers tried to make tape for it, but only 3M made a working tape for it.

The story of 3M Magnetic Tape from 1985 to the end of its production on 1995 November 14, is one of continuous improvement in quality and durability. The saga ends four years after the introduction of Nr. 996, arguably the finest analog audio tape ever manufactured. Del Eilers was the engineer behind its development and manufacture.

This book is now available for 20 $ per copy, directly from the publisher, Karen Eilers, at 11280 Kingsborough Trail, Cottage Grove, MN 55016, telephone 651-438-2344, email [email protected] .  It's not Amazon--delivery may take up to three or four weeks. But it will come.

AES - Audio Engineering Society