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Retrotechtacular: Wax On, Wax Off: How Records Are Made

In this 1942 tour of the RCA Victor plant in Camden, NJ, we see the complete record making process from the master cut production to the shipping of multiple 78RPM shellac pressings. The film centers around a recording of Strauss’ Blue Danube waltz as performed by the 1940s equivalent of studio musicians, the Victor Salon Orchestra.

The master record starts life as a thin layer of molten wax poured on to a hot circular plate in a dust-free room.  Bubbles and impurities are blow torched out, and the wax is left to cool under a steel dome. This perfect disc is carefully passed to the recording studio through a special slot, where it is laid carefully beneath the cutting stylus.

Unlike today’s multi-track recording sessions, the master was cut from the performance of a complete band or orchestra all playing as they would in concert. The sound engineer was responsible for making fast changes on the fly to ensure sonic  and groove width consistency. 

After cutting, the delicate wax undergoes several phases of electrolysis that form the metal master. It is bombarded first with pure gold and then twice with copper sulfate to build a sturdy disc. The copper ionization process also ensures high fidelity in the final product.

Although mighty, this master won’t last long enough to make all the necessary pressings, so a mother matrix is made. This is a negative image of the master. The mother is formed by electrolytically bathing the master in nickel, and then adding a thin film of some indeterminate substance. Another copper bath, and mother emerges. As soon as possible, the master is separated and whisked away to the storage vault.

Since a positive image is needed for pressing, a stamping matrix is made. Mother gets a nickel bath for durability, and then a copper bath to form the stamping matrix. Many stampers are created so that several records can be pressed at once. These images get a chromium plating to help them last through many pressings.

The stampers are soldered to a rigid backing before getting their very precisely placed spindle hole drilled. This hole is centered by machine and checked through magnification of the grooves as the disc spins. Stampers are washed one last time to remove dust and given a final brushing off and polishing.

These 78RPM records were made from the finest shellac from India, resin from the East Indies, and 18 other secret herbs and spices that are all heated and combined in a 3-story Banbury mixer. The resulting dough is rolled out into a sheet and cut into biscuits, which are square pieces slightly bigger than the final record.

The biscuits are reheated on steam tables right before they are pressed.  Label application is part of the pressing process, and both sides are pressed simultaneously. After this, the ragged edge is smoothed, and each record is tested by human ears. Finally, it is polished, sleeved, counted, boxed, and ready to be shipped to Woolworth’s, Wanamaker’s, or wherever.

A few years after this film was made, the shift to 33RPM vinyl records began. The process really hasn’t changed much over the years. The master, the mother matrix, and the stamping matrix bathe in different chemicals now, and the end result is pressed into a vinyl biscuit rather than shellac.

[Thanks Mlseim]

Retrotechtacular is a weekly column featuring hacks, technology, and kitsch from ages of yore. Help keep it fresh by sending in your ideas for future installments.

 

Comments

  1. lwatcdr says:

    So the big question is where are those masters today?

    • trandi says:

      Don’t know if it’s true or not, but here’s what a random youtuber says: “The buildings were imploded with many of the masters inside in the 60s. By then they figured there was no market left for pre-tape, mono reissues. They obviously removed ‘big sellers’, but just imagine how many interesting alternate takes or unreleased recordings might have been in there, not to mention the less popular but still worthy recordings. It’s gut wrenching!”

      Anyhow, I love their definition of “sealed, dust proof room”… it looks like an average kitchen ! :)

      Dan

      • qae says:

        Dust proof meant something different once. Dust proof pocket watches were quite the thing. They would still get some soot inside, but not so much that it would impede operation within a reasonable lifetime.

      • Greenaum says:

        Not as bad as The Great BBC Master-Tape Wiping of the 1960s and 70s. Makes your blood run cold, some of the amazing, great stuff that’s now lost to the aether. Most famously around 90 episodes of Dr Who, and Peter Cook and Dudley Moore’s “Not only, but also”. If they ever break the speed of light, they should send a probe off 50 light years away to re-pickup the broadcasts.

    • Kristina says:

      Well… some of them were destroyed in Buenos Aires (http://www.totango.net/rca.html) to make room. Some were melted down for the war. And many were destroyed by the record companies themselves (http://www.billholland.net/words/Labels%20Strive%20to%20Rectify%20Past%20Archival%20Problems.pdf).

      • Kristina says:

        From page 9 of the PDF:

        “The most spectacular case of wholesale vault trashing is the decision by RCA in the early ’60s to demolish its warehouse in Camden, N.J. The warehouse, according to collectors and industry veterans, held four floors of catalogue product, pre-tape-era material ranging from metal parts, acetates, shellac disc masters and alternate takes to test pressings, master matrix books and session rehearsal recordings.

        Several days before the demolition, officials from French RCA gained permission to go through the building and withdraw whatever material they could carry for their vinyl “Black and White” jazz reissue series. A few American collectors were also allowed in the building to salvage any items they could carry out.

        A few days later. as dozens of RCA officials and collectors stood on a nearby Delaware Bridge, demolition experts ignited the dynamite charges. Eyewitnesses said they saw “clouds of debris, black and metal chunks flying out the windows” of the collapsing building.

        The building wreckage was then bulldozed into the Delaware River. A pier was built on top of the detritus.”

        -_-

  2. Phil says:

    I thought the same when I read it.

  3. F says:

    So the content companies want to tip international law on its head and turn us all into criminals for possessing the same stuff that they are destroying because they don’t have room for it.

  4. Hack Man says:

    How It’s Made – Vinyl Records

  5. Uri says:

    Before someone gripes about this being Not a Hack, let me say I really appreciated seeing how they did make those masters and how many different technologies and crafts were involved in their construction. Thanks H A D

  6. SATovey says:

    Just think about how much money the RCA lost from destroying those recordings.
    The fact that a recording is no longer in the minds of the public as far as the top 40 is concerned, does not negate the future profits that can be earned through future sales.

    As brilliant as they were in the 60′s, they were extremely short sighted in regards to business practices and the technology they developed.

    Remember how an 16 bit processor and a megabyte of drive storage space was all you would ever need?
    Remember when the 1 Gigabyte drive was to big to fill?

    It seems that industry has a perpetually chronic disease called short sightedness.

  7. mlseim says:

    Retrotechtacular is one of my favorite features on HAD. They are not “hacks”, but they give insight into the inventiveness and creativity that gave us what we have today. Some day, we’ll run out of “Retrotechtacular” YouTube vids to watch, but for now, if we find them, let’s submit them to HAD. Or if you have sources, upload them to YouTube.

  8. Veteran says:

    Military today still uses tape over HDs for high volume storage since lifetime is more stable and overall densities and speed with multistreams are very fast. So what you thought was old is once again new.

  9. Eugene says:

    Data is in danger of being lost all the time. What was state of the art storage technology becomes obsolete. How many people have 5.25 of 3.5 floppies stored away and don’t have a machine with a floppy drive (yes, I have successfully read 20 year old floppies). How long before optical drives will go the same way. Even NASA has trouble this. Volunteers are trying to recover photos from magnetic data tapes from the original Lunar Orbiter missions. http://www.rockethub.com/projects/14882-lunar-orbiter-image-recovery-project

  10. reptarju says:

    Atrocities of demolition aside, with all the electroplating and other elemental cladding, how does this affect fidelity?(negating the dust free room and bare hand scrubbing of the master concept)

    example of inverse opposition:

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