The Stearic Acid Chronicles
On these following pages I will attempt to tell the story about making recording blanks in more detail. It is my own personal story. I do not claim now, nor will I ever claim, that my one particular set of methods and findings is the "correct" or "absolute" way to make them. I have found, so far, one set of methods that works well and produces good blanks. Every one of the people who are now producing these will say the same thing: For each person who starts off making these, it becomes a highly individualized process.
There are so many variables that affect the final outcome, and these variables differ significantly with every different kind of mold, and with different brands and types of raw materials, that it ends up being a highly personalized process for anyone who decides to do it.
The men who laid the foundation for this in the years from about 1880 to the mid 1890s or so, did thousands of experiments before the basic brown wax compound was found. Edison had a staff of chemists and a large laboratory where these experiments were carried out. Not until around experiment #1029 (or thereabout), was success achieved.
Indeed, even after that, there was more trouble for them, because those early blanks oozed liquid out on hot days and had to be recalled. After a few more adjustments to the formula, that was fixed. The result was the basic brown wax that has been used ever since.
It was a secretive and proprietary process. Clues have been left in patent records and in transcriptions of court cases dealing with patent infringement suits. However, no matter how good or how sparse the documentation is from those days, there are things left to the modern experimenter that only the process itself can teach.
Another consideration is the batch size. The amount of wax made back when millions of cylinder records were being produced was necessarily large. Some contemporary accounts mention wax being cooked in 900 pound kettles. The batch size, the heat transfer, the chemical reaction itself all are interdependent.
Coming along some 120 years later and making small batches to make a few cylinders is quite a bit different than operating a large factory. So, that ends up producing the situation where what was done before, 120 years ago, serves as a good solid guide. But it is only a guide because things change when the batch size is changed.
Also to be considered is the fact that the ingredients themselves are somewhat different now, than they were then. Back then all they had was double-pressed animal tallow based stearic. Now we have triple-pressed stearic in many different bases, both animal and vegetable. Triple pressed stearic is more refined than the old double-pressed was. Double-pressed is still available, although not common. The ceresin wax used as tempering is now synthetic, not natural as in the old days. So, all of that comes into play when making modern-day brown wax.
With those things in mind then, I will attempt to tell the story of some of the things that I have found out so far. There have been some exciting moments, and some disappointments along the way. Mostly though, it has involved defining the variables and then isolating each one and doing experiments with it to find out the best overall value for it. The trick there is to try and only change one thing at a time, meanwhile leaving everything else alone.
There are at least a dozen of these variables that are all happening at the same time throughout the waxmaking and blank casting operations.
Here are the rough contents of these pages:
