Coketron - the "Real" Story from Peter Keller :) :) :)


 

Peter Keller asked me to pass this along to the group.

I'm sure he was smiling the entire time he wrote it.

Dennis Tillman W7pF



I guess it is time for the real story of the Coketron to be exposed.



The Coketron was originally developed for the cost reduction of the 545-B
with the new 545-C [ 545-C nomenclature - C for "Cokescope" ].



Advantages of the "Cokescope" included:

1. Lower material cost - Coke bottles only cost a few cents vs. several
dollars for CRT bulbs.

2. Independence from on-time supply issues caused by labor strikes at
Lancaster Glass and periodic flooding of the Corning Glass plant by the
nearby Chemung River. Coke bottles were always available anywhere.

3. Added employee benefits at Tek - the Coke bottles had to be emptied
by the bulb prep group before use.



The disadvantages that caused the program to be cancelled were pattern
distortions and how-the-heck do you paint the accelerator helix on the
double reentrant curve of the bottle? Also, the glass 2-liter Coke bottles
necessary to better fill the big round hole in the 545-C front panel were
not yet perfected. 2-liter plastic Coke bottles were tried but they tended
to sag into strange shapes at bake-out.



Seriously though, Tom Lee was closest.

Two Coketrons were made several years apart in the Engineering Tube Lab just
to show that it could be done. The first used a T3100 or T3160 gun and
worked surprisingly well. I can remember it displaying the crosshatch
pattern generated by the CRT engineering B2 test sets. Unfortunately, the
tube later rolled off a bench and failed the impromptu drop test. I believe
it was during a lab move.



The second tube used a T2110 gun and suffered a cracked bulb due to thermal
coefficient mismatch of the glasses during processing. This was repaired and
became the tube pictured in my book. This one did not have phosphor on the
screen but glass fluorescence would usually suffice to display a trace. Both
tubes did have complete electron guns with deflection plates. I can't recall
the second tube actually being operated but excessive gas levels due to
little or no bake-out because of the TC mismatch might have been the reason.
I remember it was mainly constructed for photos since we had none of the
first tube.



There you have the rest of the stories. Take your pick!



All of this was 30+ years ago so memories are a little fuzzy.



Peter Keller


Tom Lee
 

Sent from my iThing, so please forgive the terseness and typos.

On Jan 15, 2021, at 6:01, "Dennis Tillman W7pF" <dennis@ridesoft.com> wrote:

Peter Keller asked me to pass this along to the group.

I'm sure he was smiling the entire time he wrote it.

Dennis Tillman W7pF



I guess it is time for the real story of the Coketron to be exposed.



The Coketron was originally developed for the cost reduction of the 545-B
with the new 545-C [ 545-C nomenclature - C for "Cokescope" ].



Advantages of the "Cokescope" included:

1. Lower material cost - Coke bottles only cost a few cents vs. several
dollars for CRT bulbs.

2. Independence from on-time supply issues caused by labor strikes at
Lancaster Glass and periodic flooding of the Corning Glass plant by the
nearby Chemung River. Coke bottles were always available anywhere.

3. Added employee benefits at Tek - the Coke bottles had to be emptied
by the bulb prep group before use.



The disadvantages that caused the program to be cancelled were pattern
distortions and how-the-heck do you paint the accelerator helix on the
double reentrant curve of the bottle? Also, the glass 2-liter Coke bottles
necessary to better fill the big round hole in the 545-C front panel were
not yet perfected. 2-liter plastic Coke bottles were tried but they tended
to sag into strange shapes at bake-out.



Seriously though, Tom Lee was closest.

Two Coketrons were made several years apart in the Engineering Tube Lab just
to show that it could be done. The first used a T3100 or T3160 gun and
worked surprisingly well. I can remember it displaying the crosshatch
pattern generated by the CRT engineering B2 test sets. Unfortunately, the
tube later rolled off a bench and failed the impromptu drop test. I believe
it was during a lab move.



The second tube used a T2110 gun and suffered a cracked bulb due to thermal
coefficient mismatch of the glasses during processing. This was repaired and
became the tube pictured in my book. This one did not have phosphor on the
screen but glass fluorescence would usually suffice to display a trace. Both
tubes did have complete electron guns with deflection plates. I can't recall
the second tube actually being operated but excessive gas levels due to
little or no bake-out because of the TC mismatch might have been the reason.
I remember it was mainly constructed for photos since we had none of the
first tube.



There you have the rest of the stories. Take your pick!



All of this was 30+ years ago so memories are a little fuzzy.



Peter Keller








Tom Lee
 

Thus makes me want to go and build one and hook it up to my 545!

Sent from my iThing, so please forgive the terseness and typos.

On Jan 15, 2021, at 6:01, "Dennis Tillman W7pF" <dennis@ridesoft.com> wrote:

Peter Keller asked me to pass this along to the group.

I'm sure he was smiling the entire time he wrote it.

Dennis Tillman W7pF



I guess it is time for the real story of the Coketron to be exposed.



The Coketron was originally developed for the cost reduction of the 545-B
with the new 545-C [ 545-C nomenclature - C for "Cokescope" ].



Advantages of the "Cokescope" included:

1. Lower material cost - Coke bottles only cost a few cents vs. several
dollars for CRT bulbs.

2. Independence from on-time supply issues caused by labor strikes at
Lancaster Glass and periodic flooding of the Corning Glass plant by the
nearby Chemung River. Coke bottles were always available anywhere.

3. Added employee benefits at Tek - the Coke bottles had to be emptied
by the bulb prep group before use.



The disadvantages that caused the program to be cancelled were pattern
distortions and how-the-heck do you paint the accelerator helix on the
double reentrant curve of the bottle? Also, the glass 2-liter Coke bottles
necessary to better fill the big round hole in the 545-C front panel were
not yet perfected. 2-liter plastic Coke bottles were tried but they tended
to sag into strange shapes at bake-out.



Seriously though, Tom Lee was closest.

Two Coketrons were made several years apart in the Engineering Tube Lab just
to show that it could be done. The first used a T3100 or T3160 gun and
worked surprisingly well. I can remember it displaying the crosshatch
pattern generated by the CRT engineering B2 test sets. Unfortunately, the
tube later rolled off a bench and failed the impromptu drop test. I believe
it was during a lab move.



The second tube used a T2110 gun and suffered a cracked bulb due to thermal
coefficient mismatch of the glasses during processing. This was repaired and
became the tube pictured in my book. This one did not have phosphor on the
screen but glass fluorescence would usually suffice to display a trace. Both
tubes did have complete electron guns with deflection plates. I can't recall
the second tube actually being operated but excessive gas levels due to
little or no bake-out because of the TC mismatch might have been the reason.
I remember it was mainly constructed for photos since we had none of the
first tube.



There you have the rest of the stories. Take your pick!



All of this was 30+ years ago so memories are a little fuzzy.



Peter Keller








Roy Thistle
 

On Fri, Jan 15, 2021 at 06:28 AM, Tom Lee wrote:


makes me want to go and build one
Not to imply one thinks it is... but, it is not so easy... even if one's institution funds a glass fabrication shop (and many no longer do)... and has a skilled scientific glassblower (Dodos may be rarer.)... and one has a source of electron gun assemblies... and one has available high vacuum technology.
Back then electron gun assemblies (basically, the entire rear end of a CRT: from pins, to electron gun... including a getter... and a nipple for evacuation) ... those assemblies were readily available... although sourcing assemblies with deflection plates for electrostatic deflection would probably have been harder. (... electron gun assemblies for CRTs using electromagnetic deflection were being manufactured in the 10s of millions?... specialty ones for electrostatic deflection, not so much.)
Fabricating a reasonable electron gun assembly would probably be an order of magnitude higher, and probably a project breaker too, for most.
Given one has access to the "men and materials," it is not so easy as chucking up a coke bottle on one end of a glass lathe, and a crt assembly on the other end... and then having a go at it with a double headed torch.
There is a technology of skill, and materials, to making successful glass to glass seals that are sufficiently vacuum tight and sufficiently stress free that the seal lasts.
And what about a phosphor... is the visible cathodoluminescence of soda lime glass alone sufficient, given it is the bottom of a bottle being struck.
But about these things... maybe, we shall see.


Michael A. Terrell
 

Glass bottles were half gallon, not two liter.

On Fri, Jan 15, 2021 at 9:01 AM Dennis Tillman W7pF <dennis@ridesoft.com>
wrote:

Peter Keller asked me to pass this along to the group.

I'm sure he was smiling the entire time he wrote it.

Dennis Tillman W7pF



I guess it is time for the real story of the Coketron to be exposed.



The Coketron was originally developed for the cost reduction of the 545-B
with the new 545-C [ 545-C nomenclature - C for "Cokescope" ].



Advantages of the "Cokescope" included:

1. Lower material cost - Coke bottles only cost a few cents vs. several
dollars for CRT bulbs.

2. Independence from on-time supply issues caused by labor strikes at
Lancaster Glass and periodic flooding of the Corning Glass plant by the
nearby Chemung River. Coke bottles were always available anywhere.

3. Added employee benefits at Tek - the Coke bottles had to be emptied
by the bulb prep group before use.



The disadvantages that caused the program to be cancelled were pattern
distortions and how-the-heck do you paint the accelerator helix on the
double reentrant curve of the bottle? Also, the glass 2-liter Coke bottles
necessary to better fill the big round hole in the 545-C front panel were
not yet perfected. 2-liter plastic Coke bottles were tried but they tended
to sag into strange shapes at bake-out.



Seriously though, Tom Lee was closest.

Two Coketrons were made several years apart in the Engineering Tube Lab
just
to show that it could be done. The first used a T3100 or T3160 gun and
worked surprisingly well. I can remember it displaying the crosshatch
pattern generated by the CRT engineering B2 test sets. Unfortunately, the
tube later rolled off a bench and failed the impromptu drop test. I believe
it was during a lab move.



The second tube used a T2110 gun and suffered a cracked bulb due to thermal
coefficient mismatch of the glasses during processing. This was repaired
and
became the tube pictured in my book. This one did not have phosphor on the
screen but glass fluorescence would usually suffice to display a trace.
Both
tubes did have complete electron guns with deflection plates. I can't
recall
the second tube actually being operated but excessive gas levels due to
little or no bake-out because of the TC mismatch might have been the
reason.
I remember it was mainly constructed for photos since we had none of the
first tube.



There you have the rest of the stories. Take your pick!



All of this was 30+ years ago so memories are a little fuzzy.



Peter Keller









 

My copy of the book just arrived (thanks Dennis!) and I see that I misunderstood how the Coketron was constructed. I had thought that the cathode and deflection plates were inserted into the neck of the Coke bottle, but they are actually contained in their own cylindrical envelope that is merely joined to the mouth of the Coke bottle. That also goes some way toward explaining why they had difficulty with the glass-to-glass joint (though I wonder why they didn't make the other envelope from Coke bottle glass. I suppose that the glass used for the envelope has specific material properties to make a good seal around the metal pins, or something similar)


Tom Lee
 

Instructions for the humor- and google-impaired, eh?

I never imagined that there would be a need to distinguish what one would do for a one-off hack, from what one does for a commercial product. Silly me.

If one wanted to simplify things to the barest bones, you'd do something not too far off from what the Coketron looks like: A mash-up of two already-manufactured items. You can buy a 1EPx crt -- they're still around on ebay and the like. Not cheap, but not out of the question for a one-off, either. Carefully cut off the face, maybe using the hot-wire-shock technique. This will be a low-yield process.

That gives you a base with pins (so you don't have to master the tricky art of making feedthroughs), the gun, the grids and the deflection plates, all pre-made and pre-aligned.

What about the phosphors? Easy peasy -- just do what Ferdinand Braun did for the first crt: Crush up some willemite (readily available from mineral shops; very cheap), make a slurry with some water and pour a bit into the coke bottle. Swish it around. Let dry. There's your screen.

Ordinary xerox paper would work, too, but the Coke bottle shape doesn't make that too practical. But the fluorescent bleach used to make paper look whiter also lights up quite nicely under electron bombardment. My guess is that you could probably mix laundry bleach with some other goo to make a workable phosphor, too. But that sounds an awful lot like chemistry or materials science, and I'm four years shy of a degree in either.

The trickiest part is to join the two subassemblies. I probably wouldn't try abutting them. Rather, I'd interpose a cylindrical piece, after having made a nipple in it for connecting the vacuum pump. Join the Coke bottle to one end of the cylinder, the gun to the other, then fire up the vacuum pump. Maybe use my homebrew induction ring to heat up the gun to drive out any adsorbed gas picked up after cracking it open.

Want to get fancy? Wind a PDA helix around the Coke bottle for increased intensity. Focus won't be too great, but hey -- /it's a Coke bottle crt/. The point isn't to compete with the 7104's MCP.

--Tom

--
Prof. Thomas H. Lee
Allen Ctr., Rm. 205
350 Jane Stanford Way
Stanford University
Stanford, CA 94305-4070
http://www-smirc.stanford.edu

On 1/15/2021 09:28, Roy Thistle wrote:
On Fri, Jan 15, 2021 at 06:28 AM, Tom Lee wrote:

makes me want to go and build one
Not to imply one thinks it is... but, it is not so easy... even if one's institution funds a glass fabrication shop (and many no longer do)... and has a skilled scientific glassblower (Dodos may be rarer.)... and one has a source of electron gun assemblies... and one has available high vacuum technology.
Back then electron gun assemblies (basically, the entire rear end of a CRT: from pins, to electron gun... including a getter... and a nipple for evacuation) ... those assemblies were readily available... although sourcing assemblies with deflection plates for electrostatic deflection would probably have been harder. (... electron gun assemblies for CRTs using electromagnetic deflection were being manufactured in the 10s of millions?... specialty ones for electrostatic deflection, not so much.)
Fabricating a reasonable electron gun assembly would probably be an order of magnitude higher, and probably a project breaker too, for most.
Given one has access to the "men and materials," it is not so easy as chucking up a coke bottle on one end of a glass lathe, and a crt assembly on the other end... and then having a go at it with a double headed torch.
There is a technology of skill, and materials, to making successful glass to glass seals that are sufficiently vacuum tight and sufficiently stress free that the seal lasts.
And what about a phosphor... is the visible cathodoluminescence of soda lime glass alone sufficient, given it is the bottom of a bottle being struck.
But about these things... maybe, we shall see.




Roy Thistle
 

On Fri, Jan 15, 2021 at 10:33 AM, Tom Lee wrote:


Join the Coke bottle to one end of the cylinder, the gun to the other
Then one would have two seals to de-stress... the vacuum is pulled by removing the base, on the electron gun assembly... and attaching glass tubing there to pull the vacuum.
I know it is supposed to be funny... or a joke... but, the Coketron depicted in Peter's book is a prop... and we don't know for certain if any Coketron like that ever worked, or if one did... for how long...or what kind of external support was required.
We do know these were fabricated at a Tektronix CRT lab, employing specialized skills and technology that are now mostly lost.
Anyway, it isn't funny when people get it into their heads to "make" something like a Coketron... and fruitlessly waste several 1EP1s or other working miniature CRTS, to do a YouTube video. There are people out there that don't understand the joke.


Roy Thistle
 

On Fri, Jan 15, 2021 at 09:53 AM, Jeff Dutky wrote:


I suppose that the glass used for the envelope has specific material
properties to make a good seal around the metal pins, or something similar)
The coefficient of thermal expansion, of the glass, has to sufficiently match that of the material to be embedded in the glass, or joined to the glass. And, the molten glass has to be able to wet it. Many/Most? CRTs, and vacuum tubes, used Dumet wire for the glass to metal seals.
I don't find this information mentioned in Peter's book; but, it is widely discussed, in other sources.


Chuck Harris <cfharris@...>
 

Fundamentally, the only problem is we don't know
what type of glass was used for the coke bottle, and
what type of glass was used for the 1EP1. Most likely
the 1EP1 is a laboratory grade of leaded flint glass,
and the coke bottle isn't.

So, if you fuse the two together, there will be subtle
differences in the expansion characteristics of each
glass, leading to a crack, when the glass is cooled
sufficiently below the temperature where the glasses
were fused.

There are several ways to work around this problem.

The easiest would be to use an intermediate material
between the two glasses, such as the lead frit that
is used to "solder" the screens of CRT's to the funnel
section. Lead frit is a very highly leaded glass, that
can contain as much as 50% lead. The lead frit melts
at a much lower temperature than ordinary glasses, and
forms a very strong seal. It is used for things like
mating leaded glass funnel sections to CRT screens.

Indium solder can also be used.

Another way, would be to make a cylindrical center metal
section out of stainless steel, and form a "housekeeper"
seal on each end that is fused to the glass.

Housekeeper seals are made on a lathe by turning the
edge of the stainless steel cylinder into a long slow
tapering knife edge... like you would need if you were
planning to use the stainless steel cylinder to cut
disks out of leather.

Because the edge that is bonded to the glass is only
1-1.5 thousandths of an inch thick, and the taper is about
3/8 inch long, the stainless will stretch to adapt to the
differential expansion characteristics of stainless and
glass.

They can be effectively done for diameters in the 1/4 to
2" range.

These techniques are well known, and certainly not beyond
the capabilities of any technical glass blower.

-Chuck Harris



Roy Thistle wrote:

On Fri, Jan 15, 2021 at 10:33 AM, Tom Lee wrote:


Join the Coke bottle to one end of the cylinder, the gun to the other
Then one would have two seals to de-stress... the vacuum is pulled by removing the base, on the electron gun assembly... and attaching glass tubing there to pull the vacuum.
I know it is supposed to be funny... or a joke... but, the Coketron depicted in Peter's book is a prop... and we don't know for certain if any Coketron like that ever worked, or if one did... for how long...or what kind of external support was required.
We do know these were fabricated at a Tektronix CRT lab, employing specialized skills and technology that are now mostly lost.
Anyway, it isn't funny when people get it into their heads to "make" something like a Coketron... and fruitlessly waste several 1EP1s or other working miniature CRTS, to do a YouTube video. There are people out there that don't understand the joke.






Chuck Harris <cfharris@...>
 

Dumet wire was designed to nearly perfectly match the expansion
characteristics of leaded flint glass. The wetting of dumet
is handled by plating the metal with copper, which wets glass
very nicely. It also gives the seal area the characteristic
pinkish orange color.

I am not certain, but I think I recall that Dumet comes from a
contraction of the words dual and metal.

-Chuck Harris

Roy Thistle wrote:

On Fri, Jan 15, 2021 at 09:53 AM, Jeff Dutky wrote:


I suppose that the glass used for the envelope has specific material
properties to make a good seal around the metal pins, or something similar)
The coefficient of thermal expansion, of the glass, has to sufficiently match that of the material to be embedded in the glass, or joined to the glass. And, the molten glass has to be able to wet it. Many/Most? CRTs, and vacuum tubes, used Dumet wire for the glass to metal seals.
I don't find this information mentioned in Peter's book; but, it is widely discussed, in other sources.






Ken Eckert
 

In the scientific world, borosilicate glass (pyrex being Cornings name) electrical connections through the glass is done with tungsten using an intermediate of uranium glass.

The uranium glass goes onto the tungsten to form a bead then the lead is positioned in the hole in the pyrex and the uranium glass is flowed into the pyrex....


greenboxmaven
 

Whether the Coketron was actually constructed or not, I remember from years ago that picture tube rebuilders would not accept "green glass" duds for rebuilding. I can't recall ever seeing a jug that was green glass, but from the concerns in this conversation, I wonder if the issue for the rebuilders was different expansion characteristics of the new neck and the re-used envelope.

Bruce Gentry, KA2IVY

On 1/16/21 9:24, Chuck Harris wrote:
Fundamentally, the only problem is we don't know
what type of glass was used for the coke bottle




Roy Thistle
 

On Sat, Jan 16, 2021 at 09:31 AM, greenboxmaven wrote:


would not accept "green glass"
I don't think they meant the actual "jug"/envelope... what they were referring to was the uranium containing glass that was used as a graded seal (a combination of different glasses [with different coefficients of expansion] that forms a stepped gradient).., used to seal the lead-ins and pins into the base at the neck.
It is sometimes called "green glass" because it does have that pale green colour... and glows bright green... like a CRT trace... when exposed to ultraviolet light.
It could be that they used it in the envelope too... but, I don't see why... as leaded soda lime glass would have been cheaper... the uranium stuff was expensive.
I guess they were spooked by the words uranium and radiation... exor the workers were... and the company didn't want liability. The radiation, even in heavily doped uranium glass, was very low.


Thomas Garson
 

I hope that was/is depleted uranium!

Just for the record, Corning sold the rights to the name Pyrex years ago. Last I was in Corning, it appeared they had shut down all operations there, with the exception of the museum and Steuben Ware facility. The current owner of Pyrex brand uses soda lime glass, which is not nearly as good but, according to my reading, is much cheaper to make. Do NOT take modern Pyrex from freezer to oven!

Thomas Garson
Aural Technology, Ashland, OR
By my calculation, the dynamic range of the universe is roughly 679dB,
which is approximately 225 bits, collected at a rate 1.714287514x10^23 sps.

On 1/16/21 8:49 AM, Ken Eckert wrote:
In the scientific world, borosilicate glass (pyrex being Cornings name) electrical connections through the glass is done with tungsten using an intermediate of uranium glass.
The uranium glass goes onto the tungsten to form a bead then the lead is positioned in the hole in the pyrex and the uranium glass is flowed into the pyrex....


Roy Thistle
 

On Sun, Jan 17, 2021 at 12:51 AM, Thomas Garson wrote:


Corning sold the rights to the name Pyrex years ago
I think, the name Pyrex is not sold... but, only licensed out... so that Corning can still use it.
Fischer Scientific... here in the colonies at least... still sells Pyrex branded laboratory glassware, listed as being borosilicate glass.
The same is still listed in the Corning Life Sciences catalog... a division of Corning.
Though there are/were some bake ware, and measuring cups, and the like... that had/have Pyrex on them that are indeed soda lime glass... some of those items are actually borosilicate.


Dave Wright
 

I have wanted for years to get into technical glass, perhaps 'retirement' will allow..?

In the meantime, this fellow would be my candidate for fabrication of the 21st Century CokeTron...

https://www.daliborfarny.com/story/

_Dave KC6UPS


KeepIt SimpleStupid
 

Comments:  There seems to be a little too much quoting in this thread. 

Following instructions must be hard.
Fabrication is probably within my skill set.  Just don't have the equipment at home. 

I used to occaisionally seal zinc and phosforous in square quartz tubes using a Hydrogen/Oxygen flame under high vacuum for synthesis.
The first step was to attach a round tube to the square tube and seal off the end.  Cajon fittings were used to attach to the high vacuum system.  A Piranni gauge was used to measure the high vacuum.  the diffusion pump was liquid nitrogen cooled.
I also sealed small tubes with a precision hole drilled with high voltage into a larger tube.  That was necked down to attach even a smaller tube that was sealed off under vacuum.
If I hadn't done it in while, I'd have to practice at least once to get the "feel" again.

I only messed up once dropping a hot tube of red phosforus and inc on the table below.

It's not hard when you can solder, braze, silver solder, weld (TIG, stick, MIG).   I tried my luck welding after being set up and my first welds were considered very good.
I had some experience with Borosilicate glass with a propane/Oxygen torch.
A diamond wafer saw would be able to cut the glass.
I only had a few weeks to pick up the sealing art and I taught someone else.


Stephen Hanselman
 

Thanks for the thread, this is very interesting!

Regards,

Stephen Hanselman
Datagate Systems, LLC

On Jan 18, 2021, at 12:25, KeepIt SimpleStupid via groups.io <keepitsimplestupid=yahoo.com@groups.io> wrote:

 Comments: There seems to be a little too much quoting in this thread.

Following instructions must be hard.
Fabrication is probably within my skill set. Just don't have the equipment at home.

I used to occaisionally seal zinc and phosforous in square quartz tubes using a Hydrogen/Oxygen flame under high vacuum for synthesis.
The first step was to attach a round tube to the square tube and seal off the end. Cajon fittings were used to attach to the high vacuum system. A Piranni gauge was used to measure the high vacuum. the diffusion pump was liquid nitrogen cooled.
I also sealed small tubes with a precision hole drilled with high voltage into a larger tube. That was necked down to attach even a smaller tube that was sealed off under vacuum.
If I hadn't done it in while, I'd have to practice at least once to get the "feel" again.

I only messed up once dropping a hot tube of red phosforus and inc on the table below.

It's not hard when you can solder, braze, silver solder, weld (TIG, stick, MIG). I tried my luck welding after being set up and my first welds were considered very good.
I had some experience with Borosilicate glass with a propane/Oxygen torch.
A diamond wafer saw would be able to cut the glass.
I only had a few weeks to pick up the sealing art and I taught someone else.










Roy Thistle
 

On Sun, Jan 17, 2021 at 08:23 PM, Dave Wright wrote:


I have wanted for years to get into technical glass, perhaps 'retirement' will
allow..?
It might.
I've had training it it... and it is both demanding and fascinating.
If you are interested: I started a group: ScientificGlassblowing@groups.io