North American Edison blank Pour streaks?

[edisonphonoworks]

As Usual, I notice odd things in brown wax records, that I do not think anyone else notices. I have a few North American Era cylinders (1890-1894) Of course made on Edison Phonograph Works blanks. What I find curios is pour streaks, as us in the industry call them. Pour streaks are bands of dark wax formed during pouring wax into a cylinder mould, usually caused by the mold too cool or the wax too cool, and formed when you first pour the wax, when filling the mold, it is the first wax that sticks to the core, and does not quite melt in with the other wax. If the core is too cool, if you do not move your pour pot around, it forms a dark band of wax. The core on these old moulds might have been cool, I do know that factory pouring temp for blanks was only 330F, a low temperature. The mold at this time also had a cap, with an air vent on one side, and a round bulge, that one filled the mold with, as a built in funnel. As it has a specific pour spot, this pour streak would be caused with a low wax temp or cool mold. I will admit, it seems that despite this, North American era Edison Phonograph Works Blanks, actually to me seem quieter than later blanks. North American Edison's only have a single spiral, like Columbia blanks do, when they started making their own blanks, about 1896-1897. I also am trying to find when Edison switched form single spiral moulds to double spiral moulds. Perhaps he did this when Columbia started producing their own blanks to physically distinguish an Edison from a Columbia. Previous to 1896(and even into 1897) most Columbia cylinders were made on Edison blanks, by mid to late 1897 Columbia had its technical problems solved and were able to make blanks in house based on the research of Evansville Indiana Soap Maker Adolph Melzer who answered the call of an ad in the American Soap Makers Journal "a thoroughly practical man, who can work with soaps, not for washing purposes."
http://tinfoil.com/cm-1609.htm
Is a link to an early Columbia cylinder made on a North American Edison Phonograph Works blank, notice also it too has that curious angled pour streak.

[Chuck]

That is very interesting! It just goes to show that
things have not changed much during the intervening
120 years. It proves that those gentlemen back then
faced the same difficulties that we now are still
dealing with! It also serves as evidence that
what we are doing now must be quite similar to what they were doing back then.

The pouring streak does tend to mostly disappear when
the mold is preheated to the same temperature as the
liquid wax when it is poured in. For me, that
temperature is 450 degrees F. Shawn, I know that your
whole process seems to work better about 100 degrees F
lower than mine does.

Not exactly sure why this is, but I do know for sure
that if I lower the mold preheat and the wax temperature
at pour time down to 425 F, the blanks start getting
bubbles trapped in them, and all sorts of other very
bad things start to happen.

For me, high temperature is the answer.
And, yes, I have had wax batches on fire several times
and some of those batches have made some very nice cylinders indeed!

[edisonphonoworks]

Chuck Yes, it seems wax that has been hot enough to catch on fire, has made some nice blanks (this is only if it does it before ceresin is added, if ceresin gets too hot, it ruins it). I still think that different densities of molds alter the pre heat on them, and the material. My molds are pretty massive, the base on the right handed mold being 2" thick steel and the other left handed mold 3" solid steel. These bases seem to hold heat a long time, at 350 pre heat, on a hot summer day of 90 degrees, it takes 90 minutes still to set, about the same as your wax.

[Chuck]

Yep! Shawn you've sure got that right!
There are subtle differences between different types
of molds. Mine uses a combination of 6061 T6 aluminum
and plain 1020 mild steel. The center rod on the
base may be 1045 steel, not sure, it is just a hunk of
round stock the machinist grabbed when it was made.

Yes, there it is in your previous post! Your temperature
of 350 F is exactly 100 degrees F lower than what I use.

Why is this? Who knows? This is just a small example
of the Black Art of all of this, which is a part of it.

By the way, for anyone who is curious, I just
put up the drawing of my mold on my web site.

Go to http://www.richardslaboratories.com
and click on the new main menu selection titled
"My Mold". That mold has cast exactly 381 blanks
since August, 2009, when the very first casting
dropped out of it.

[BusyBeeCylinder]

Since we are sharing....here is a couple pics of my mold for making blanks. I've certainly not made nearly as many as Chuck or Shawn...have to say the best blanks were those that were made at temps close to the flash point (or in some cases after I put the fire out). haven't used it in years (at least not for making blanks....serves as a door stop now).


Thanks,
Rob

[edisonphonoworks]

My mold, was designed by myself, based some on Chuck Richard's mold and my Uncle Mark Stuart, and McHenry Machine Shops input. It was made in 2010. The mold stands with base 10 ½" tall the core 8" tall the outer tube 7" tall. The taper was cut on a CNC lathe. I first tested this with a piece of walnut, and we went a little too thin on the wood core, however it makes the perfect reaming core. While the blank is in the mold the wooden core is inserted in the bore, and shrinks onto the core, which is lubricated with graphite. The spiral thread was cut by placing a sharpie in the lathe, and using an allen wrench, the gearing set at ½ thread per inch, this is too course for the lathe to cut, so I hand filed for 3 hours each spiral with a chain saw sharpening file, roughing it in, and then wen sufficiently deep, turned the lathe on slow, and let the file go down the spiral, until deep enough. As crude as that is, the cylinders rarely need reaming and fit without wobble on the mandrel. The mold heated in an oven for 1 hour at 350 and the wax poured in and 70-90 minutes for the core to be pulled and 10 min for the blank to come out of the mold, wax temp for my mold is best at 450F, Once ceresin is added the wax must never go over this, or the ceresin will burn. I also want to add that the rough casting is 7" long, and the trimmed parts are saved, heated and filtered and used to make blanks. It can make blanks for the 20th century machines, if someone has a recorder. I have made dictation machine blanks, but I have to alter the wax slightly to shrink more, so it engages with the Ejectomatic on Ediphones, so I rarely make dictation blank (I have made 7 in the past.)The blanks come out at 2.33" and then shaved down to 2.25" to season, then when used or purchased shaved down to around 2.196".

[Chuck]

Yeah Shawn, I definitely think you are on to something
good there, with your 2.33 inch diameter blanks as they
come out of the mold.

My mold has its outer cylinder bored to 2.254 inch diameter.

This results in a blank coming fresh out of that
steel cylinder having a typical diameter of about
2.202 or so. Usually the top of the casting is of
slightly different diameter than the bottom, due to
the way the wax shrinks after it cools down.

If I had anything to do differently next time I make
another mold, I think it would probably be bumping
up the inside diameter of the outer steel cylinder a
slight bit.

Your's come out at 2.33 diameter, where as mine
come out at about 2.202 diameter.

That is a difference of .128 inch on the diameter.
That's a whole eighth of an inch!

The distinct advantage that your larger diameter mold
has over mine is that when you encounter one of those
finnicky castings which is loaded with rotary noise
down quite a ways into the outside of the wax, you
can still shave that noisy part off of there and still
end up with a full sized blank of 2.196 diameter.

Where as when I get one of those I have to go on a long
and very arduous "noise chase" session of shaving
down quite a way under the 2.196 ideal starting diameter.

I will not sell any which go much below about 2.150
inch diameter.

Even at that relatively low outside diameter, these
blanks still have about 9 shaves left in them
before reaching the minimum useful diameter of 2.112
inches.

Where as a full diameter ideal blank of 2.196 diameter
has more like 21 shaves in it!

Most of mine ship out at around 2.177 diameter.
That is about 16 available shaves.

I like to have at least a dozen shaves built in to
most all blanks I ship out.

A slightly larger diameter mold would better assure that.

But then comes the added work of all that initial shaving
and also the reclamation of all that wax, and trying
to clean it up and re-use it.

There is always some tradeoff with every step of
everything having to do with making these blanks.

Nothing comes for free, there are always consequences.