Odds and ends

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Re: Odds and ends

Postby Mark » Tue Aug 23, 2016 5:26 pm

Well an initial test of the high pressure air tank proved fussy. Maybe with the snorkel the beveled/rounded bottom reflects the combustion in an adverse way or maybe just being almost 2 inches shorter than the 20 ounce tank is a factor or both. I have never liked round bottom "jam jars" as much as flat bottom ones.
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Re: Odds and ends

Postby Mark » Sun Sep 18, 2016 5:28 pm

So I tried the high pressure aluminum air tank again with a shorter 3.75 inch snorkel and it ran well enough sideways but it doesn't sustain in the vertical which is the same behavior for the other (CO2) paintball tanks with a longish snorkel.

In other news I was revisiting an idea of using a typical jam jar to run it on paraffin wax. The idea being like melting a glass beer bottle that is slowly moved closer and closer to a campfire, it won't crack and as such perhaps gradually heating a jam jar with wax for fuel until it starts to smoke or reach the autoignition temperature, would have a chance of working. It might need some puffs of air to air out the jar for starting. One thing about wax as opposed to a low boiling point methanol is the fuel could be considerably hotter instead of how methanol would be sloshing against the sides of the glass making it more likely to crack, usually right at the fuel level. Thus the heat gradient between the melted wax and jar could be such that the jar might be less likely to crack.

He's putting the test tube in water whereupon the tube cracks and the erupting steam carries the vapor up and since the wax is hot enough, all it needs is air to light.
Autoignition of boiling paraffin (candle wax)
https://www.youtube.com/watch?v=VgcBeQTpApc

Flash-Fire-Autoignition
https://www.youtube.com/watch?v=suce6QNkVRI#t=2m13s

I was watching these gasoline powered jam jars and it dawns on me that much like starting a Dyna-Jet on gas, it might help if you preheated the gasoline. Dyna-Jets are easier to start if hot or until you get a few false starts to heat it up. It seems counterintuitive though, because a jam jar might become too rich to start if not careful, the vapor being heavier than air displacing the oxygen.
"After 45 minuets of trial and error, this was the end result. Unfortunately were missing about 15 seconds of footage at the start, including the lighting of it which burnt a 2cm hole in my glove."
https://www.youtube.com/watch?v=e3R9hStCHAg

Note the delay in starting as the flame dwindles and sits on the surface of the gasoline for a bit before the main pulsations start up. This happens with methanol too sometimes.
https://www.youtube.com/watch?v=Mfb1lhQs4kk

"Paraffin wax is a white or colorless soft solid derivable from petroleum, coal or oil shale, that consists of a mixture of hydrocarbon molecules containing between twenty and forty carbon atoms. It is solid at room temperature and begins to melt above approximately 37 °C (99 °F); its boiling point is >370 °C (698 °F)."

"The boiling point of methanol is 64.7 degrees Celsius, or 148.46 Fahrenheit."
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Re: Odds and ends

Postby Mark » Fri Jun 02, 2017 2:20 pm

Nature: 3D-Printing of Glass Now Possible
“We present a new method, an innovation in materials processing, in which the material of the piece manufactured is high-purity quartz glass with the respective chemical and physical properties,” explains Rapp.
http://www.kit.edu/kit/english/pi_2017_ ... ssible.php
http://www.pkm.kit.edu/english/true3dglass.php
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Re: Odds and ends

Postby Mark » Wed Jun 14, 2017 11:55 am

Patio Heater Glass Tube VS Quartz Tube
https://www.youtube.com/watch?v=xyUtriix_N0
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Re: Odds and ends

Postby Mark » Fri Jun 23, 2017 10:29 pm

Mark wrote:Patio Heater Glass Tube VS Quartz Tube
https://www.youtube.com/watch?v=xyUtriix_N0


Here's a few tests I did akin to the above.
https://www.youtube.com/watch?v=JWDlfrOAw0E
https://www.youtube.com/watch?v=IHnM3fIhntA
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Re: Odds and ends

Postby Mike Everman » Sat Jun 24, 2017 3:04 am

Which reminds me that I want to try and make some perfectly spherical Prince Rupert's drops.
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Re: Odds and ends

Postby Mark » Sat Jun 24, 2017 2:10 pm

I wonder if you could put some glitter or carbon fiber in a Prince Rupert Drop? The clear plain ones are so yesterday. I've some mahogany obsidian and some plain black softball size rocks my dad had collected in Oregon and wondered how that would do for a PRD. The other day I whacked one with a hammer and made a flake that was sharp enough to shave the hair off my arm.
Explosion of a Mass of Obsidian
https://books.google.com/books?id=qioPA ... op&f=false
https://www.youtube.com/watch?v=-ldFumDueVo
https://en.wikipedia.org/wiki/Pele%27s_tears
Lots of obsidian out there
https://www.youtube.com/watch?v=eVdpn9TbZO4#t=2m9s

Stress related tidbits
https://en.wikipedia.org/wiki/Bologna_bottle
https://www.youtube.com/watch?v=xc1whrZGOZI
I remember one time watching a show on PBS with Dale Chihuly in Seattle where they were making large artistic pieces of glass in a very spacious building with music playing as they worked. He was miffed they had made a work of art for Elton John and he offhandedly asked the students if they had stress-relieved the piece and apparently not which meant it could explode sometime in the future out of the blue.

Some spherical thoughts
https://engineering.stackexchange.com/q ... perts-drop
https://www.reddit.com/r/Physics/commen ... perfectly/

Quirky thought
"what might work on earth is to make a regular ruperts drop, then while the glass is still plastic use sonic vibrations to press the tail into the glass blob creating a sphere.//
I think what beanangel is suggesting, in his inimitable way, is almost a Prince Rupert's Klein bottle. You protect the tail by putting it inside the drop."
Loris, Jan 06 2017
http://www.halfbakery.com/idea/Prince_2 ... _20Spheres
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Re: Odds and ends

Postby Mark » Sat Jun 24, 2017 4:03 pm

Update - obsidian seems a bit too hard to melt with a common torch and it might not be the best material for a Prince Rupert Drop depending on its coefficient of thermal expansion. Wonder what the best concoction of glass making ingredients makes the most impressive drop?
20 tons from a press
https://www.youtube.com/watch?v=A6NUNroyUys

Triggered with silicon carbide - a good presentation
https://www.youtube.com/watch?v=DAmNmWpxo8Q
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Re: Odds and ends

Postby Mike Everman » Sat Jun 24, 2017 4:35 pm

I was thinking drops falling down a flue long enough that they go spherical, but then somehow want to not distort when cold is instantly, somehow, applied. Liquid nitrogen vapor lower in the flue, but with baffles or something to make a sharp change in temperature, I'm thinking. We want the highest delta T possible. Liquid would be much better but you want it in there fast and the splash will distort it obviously.

I'd want glass with the highest strength and I highest thermal expansion un combination so the highest pent up stress is achieved when the exterior flash freeze is accomplished.

To get it to explode, you now need a hard point of carbide, or a diamond point.
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Re: Odds and ends

Postby Mark » Sun Jun 25, 2017 12:19 am

Bologna Flasks
"Bologna flasks (or bottles) are blown with the glass pipe like an ordinary small thick walled flask.
The only difference is that instead of putting the red hot flask into the lehr to anneal it free from
strains, it is left out in the cold air. This works in a similar way as intentional quenching on the
outside, but much less so in the interior. Therefore, the flask is toughened only on the outside,
while even a tiny scratch with a hard tip on the interior walls leads to explosion. German
encyclopaedias (Meyer 1885) ascribe the invention to a Mr. Asmadei in 1716. It must have been
discussed all over Europe in the 1740s, as the list of early literature in Krünitz (1780) shows.
It was presented to the Bolognese Academy of Sciences and Art by Balbi in 1745. ‘Bologneser
Flaschen’ are also known in German as ‘Springkolben’ (literally ‘shatter flasks’)."

Modern Thermally Toughened Glass
"De la Bastie’s invention was of no great practical use because the glasses could not be quenched
evenly. The resulting stresses often lead to failure after months without apparent external
cause. Even the modern technique of working with a stream of cold air can only toughen open
forms like sheets (e.g. car side windows), plates, or cups. The French glass company Arcoroc
(2007) produces such a ‘verre trempé’ which can be used to demonstrate the increased fracture
strength."

EXPERIMENT 3
"A plate of ‘verre trempé’ resists blows with a hammer. The tip of a normal nail gets flattened on
trying to hammer it into the plate. Even hardened nails often do not suffice to crack the glass.
It needs special pointed hammers (no nails) such as those provided to create emergency exits
through windows in cars or buses to shatter such a plate."
(From reference 3 in Wikipedia)
https://en.wikipedia.org/wiki/Bologna_bottle
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