Some allowance has to be made in discussing general industry practice
for its innate conservatism and the dearth of published information
during the mid-20th century. I have in my collection a number of
manuscript formularies from both Italian and Italo-American
pyrotechnists from the period c. 1850 - mid 1960s. Rarely does one
find anything in them that was not in contemporarily published
literature, and in the later ones, even some of that is absent.
Both ball milling and stamp milling were used through the 1920s and
'30s, I suspect because commercial meal was expensive and Depression-
era economics gave a strong incentive to save every penny one could.
In compositions of this period one finds a distinction between home-
made meal and "A dust" of commercial origin. After WWII, the home
production of meal was mostly dropped. This reflected the rising cost
of labor with respect to that of materials. In the 'sixties it was
still possible to buy commercial powder for 50 cents a pound. At that
price, why would anyone ball-mill? I saw a stamp mill like the one
illustrated in Davis's book when visiting Rozzi's plant, but it had
not been used for years.
Some things we take for granted today as standard pyrotechnic practice
seemed largely unknown to the trade until the mid-seventies or even
beyond. Right up until it disappeared from commerce, Paris green was
the usual chemical employed for blue colors, typically with potassium
chlorate, stearine, and dextrine. Calomel had become too expensive as
early as the 'twenties, and fell out of use during the Depression; the
newer organic chlorine donors had been introduced in military
pyrotechnics, but my impression is that they were not used in civilian
fireworks until after the publication of Lancaster's first edition in
1972.
Thomas G. Hitt was an early advocate of potassium perchlorate and
patented a perchlorate flash powder in 1915. This was by no means
original, because a German patent had been taken out in 1898 on the
use of such a composition for photographic illiumination. Apart from
Hitt, though, I find little evidence of perchlorate either in flash
powder or in colors through the 'sixties amongst display fireworks
manufacturers. I think it caught on a bit earlier for consumer
fireworks as perchlorate colors are listed in a formulary I have from
Fabrizi (N.J. Fireworks Co.).
There was enough contact with the Japanese industry that maybe two or
three U.S. makers tried rolling stars before then, but here again I do
not think much was done here with round stars before Lancaster's first
edition appeared, with its translated excerpt from Shimizu's
"Hanabi" (1957). One maker I knew went to the trouble of getting
copies of that book (I got mine from him, c. 1968-9). He had a
Japanese woman he knew make a partial translation, the ms. of which I
now have, but she gave up before she could finish because of
difficulty with the technical vocabulary. So far as I know this book
had very little circulation here and Lancaster's book is the first
notice that drew much Western attention to round stars. Cut and pumped
stars were all most U.S. makers knew until the 'seventies.
I well remember the use of dichromates in photography and
photolithography from my first consciousness of the family printing/
publishing business - we used to make our own gum-bichromate (sic)
plate emulsion, apply it to a grained unsensitized plate in a
'whirler,' then expose the plates under carbon arc lamps - but so far
as I know the first published notice of potassium dichromate for
protecting powdered metals in pyrotechnics was Shimizu's article in
Pyrotechnica VIII (June, 1982).
Many innovations in fireworks that have now become standard industry
practice first were published in issues of Pyrotechnica. Winokur gave
us alternatives to the old standard meal, antimony, bright aluminum
tremalons. Shimizu - what hasn't he touched on? Ammonia strobes,
firefly, crackle, on and on. Jennings-White showed that crackle could
be made with bismuth instead of red lead. Roger O'Neill brought to our
attention the varied performance of different charcoals - something
that hadn't been discussed in print since the days of MM. Bottée and
Riffault, and had been forgotten in the interim. When we compare what
we have today with what there was 30 years ago it is astonishing. It
shows the value of open discussion and the sharing and publishing of
information.
I wouldn't be too hard on Harry, because it seems to me that his
picture of what was widespread industry practice during the period he
was active in the trade is basically accurate.
On Mar 17, 6:55 am, "Lloyd E. Sponenburgh"
Post by Lloyd E. Sponenburgh Sure,
there were numberous mentions of potassium perchlorate in the
fireworks literature even at the time, but until about 1980, nobody I
knew used it for anything.
Sorry, I missed addressing that.
That you did not know anyone who used perchlorates isn't cardinal
evidence of its not being used.
"Numerous mentions" goes back.... way back. Even that little blue book
"Formulas and Trade Secrets" of 1932 has several perc formulae in its
fireworks section.
LLoyd