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Sylvania F18T8 Green fluorescent tube (A gift from James)

Sylvania F18T8 Green fluorescent tube (A gift from James)

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Amazing color, very bright tube actually. My mom saw me playing with these tubes and said that the green one was the most wonderful :D

IMG_20191008_232409.jpg Sylvania_F18T8_Blue.jpg Sylvania_F18T8_Green.jpg Sylvania_F18T8_Red.jpg

Light Information

Light Information

Manufacturer:Sylvania
Model Reference:F18T8 Green
Lamp
Lamp Type:Fluorescent
Filament/Radiator Type:Single coiled emitter coated cathode filament
Base:G13 bi-pin
Shape/Finish:Tubular tube
Service Life:approx 20k hours
Electrical
Wattage:18W
Voltage:120V
Current:0.2A
Optical
Color Temperature:Green
Physical/Production
Factory Location:Germany
Fabrication Date:Not sure
Application/Use:For general lighting

File information

File information

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Filename:Sylvania_F18T8_Green.jpg
Album name:vytautas_lamps / fluorescent tubes T8/T12
Keywords:Lamps
File Size:439 KB
Date added:Oct 02, 2019
Dimensions:2465 x 1689 pixels
Displayed:108 times
Date Time:2019:10:02 20:34:49
DateTime Original:2019:10:02 18:02:33
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FNumber:f 1.8
Flash:No Flash
Focal length:3.5 mm
ISO:187
Make:Blackview
Model:BV6000S
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James
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Oct 02, 2019 at 03:28 PM Author: James
Green tubes can be really efficient, in some cases the luminous flux can be even higher than white tubes.
HomeBrewLamps
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SodiumVapor 105843202020668111118 UCpGClK_9OH8N4QkD1fp-jNw majorpayne1226 187567902@N04/
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Oct 02, 2019 at 03:32 PM Author: HomeBrewLamps
I'd love to homebrew some green power grooves due to the green phosphors being very efficient. Unfortunately I have no glassblowing skills or machinery.

~Owen

:colorbulb: Scavenger, Urban Explorer, Lighting Enthusiast and Creator of homebrewlamps 8) :colorbulb:

James
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Oct 02, 2019 at 03:35 PM Author: James
Interesting idea! Some members have made their own PG tubes by experimenting with an ordinary blowtorch, and letting the glass blow (or rather suck) itself due to the partial vacuum inside. It probably takes a bit of practice but can be interesting to try if you have some basic mechanical skills.
sox35
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Mainly the electrical side of things


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Oct 02, 2019 at 03:37 PM Author: sox35
And a workshop to do it in, we're sadly lacking in space here

Ria in Aberdeen
It'll be all right in the end, and if it isn't all right, it isn't the end :love:

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Oct 02, 2019 at 03:37 PM Author: HomeBrewLamps
I will try that one day! I hear that the tubes shatter shortly after you add the grooves though.

~Owen

:colorbulb: Scavenger, Urban Explorer, Lighting Enthusiast and Creator of homebrewlamps 8) :colorbulb:

James
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Oct 02, 2019 at 04:49 PM Author: James
With glass you have to take your time - let it move, and then keep it as hot as you can but just under the softening temperature for another couple of minutes. Whenever hot glass is deformed it interrupts the internal molecular structure, which causes stresses that can lead to cracking. But if you keep it hot enough, the molecules will redistribute themselves and anneal out the stress, and cracking can be avoided.
vytautas_lamps
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My idol is Mylene Farmer, deal with it.


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Nov 24, 2019 at 01:09 PM Author: vytautas_lamps

With glass you have to take your time - let it move, and then keep it as hot as you can but just under the softening temperature for another couple of minutes. Whenever hot glass is deformed it interrupts the internal molecular structure, which causes stresses that can lead to cracking. But if you keep it hot enough, the molecules will redistribute themselves and anneal out the stress, and cracking can be avoided.

Hi James,
So, I came up with an idea on how to make a permanent home made powergroove. Imagine, I just made the dimples in a f20t12 tube. And to anneal it I put it in an electric oven on 350'f. or 250'C. Would be enough to anneal the glass in such temperature or should it be higher? If I keep it in there overnight would it work? I assume I would have to remove the endcaps as they would probably burn up the bakelite and the cement in the base? Ya know, not everyone can afford themselves a kiln of sorts in their garage Would this idea work all things considered?

New lighting technologies is a pity fest everywhere you look. From LEDs that last only for two months, to a never-ending global starvation of t8 fluorescent tubes.
We shall reinforce ourselves with good old full mercury t12s and HIDs made to surpass one's life, and give them all the middle finger ;

James
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Nov 24, 2019 at 02:01 PM Author: James
You have to do the annealing before the glass cools down for the first time, which would mean going straight into the oven immediately after forming each dimple. And unless you have some kind of super industrial oven I don’t think the kind of equipment you can find in your mother’s kitchen would get anywhere near hot enough! To relax the stresses in glass you have to hold it above the so-called strain temperature. This is the temperature at which the glass has a viscosity of 10^14.5 Poises, and at this point the stresses are annealed out after four hours. For soda-lime fluorescent tubing this is about 475C. Anything below this temperature has almost no effect. To relax the strain in 15 minutes then you have to go higher still to the Annealing Temperature, which corresponds to a viscosity of 10^13.0 Poises and for FL tubing this is about 515C. There would not be much left of a domestic oven at that temperature!

However there is an easier way - just use the same flame from the gas burner as used to form the glass. Once it has been shaped keep it as hot as you can without it deforming, for a couple of minutes. This will successfully relax the stresses and if you are lucky should avoid cracking.

If you are interested in this, sone good basic advice is given in the GE Lamp Glass catalogues, see for instance http://www.lamptech.co.uk/Documents/Components/GE%20-%20Lamp%20Components%20-%20Glass%20-%201990%20US.pdf

A green PG is a great idea! If I get a moment as things wind down before Xmas I will do some experimenting with more of these tubes and a wide fish-tail gas burner.
vytautas_lamps
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Nov 25, 2019 at 11:57 AM Author: vytautas_lamps
James! That article is so interesting! Couldn't get away from it! It has so much extremely useful information!
I actually thought that the bakers oven will not get that hot, but at least now I know for sure.
I am going to try the technique you described. I have a few EOL blanks that I can use as they are damned to the recycling either way. So I guess I heat the spot until the dimple is formed, then I hold it up over the flame just enough above it o prevent further glass deformation, but keep hot enough to relax the stresses. Hmm, sounds easier than in real life.. I will try it! If I manage to coach myself into feeling the right temperature and manage to create a permanent powergroove, then ohh man!

New lighting technologies is a pity fest everywhere you look. From LEDs that last only for two months, to a never-ending global starvation of t8 fluorescent tubes.
We shall reinforce ourselves with good old full mercury t12s and HIDs made to surpass one's life, and give them all the middle finger ;

James
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Nov 26, 2019 at 12:50 AM Author: James
It is a fine balance, but many other members here succeeded! Just don’t heat the glass too fast at first. When cold glass has a poor thermal conductivity and heats up too locally, which also creates stress and can cause cracking. So heat the glass up slowly over a minute or two, this causes it to become more conductive and spreads out the warmth and stresses, and then you can go for it and raise the temperature until it deforms.

If your gas burner allows it, the first thing you should do is use a large soft flame without air such that it has yellow glowing soot particles. Waft this over a large area of glass until it has a thin black coating of soot, then allow a small amount of air into your burner to create a bluish soot-free flame and continue heating gently. When the glass reaches about 400C the soot will oxidise to CO2 and disappear, and this serves as a good indicator that the glass is then hot enough to receive its final heating and be deformed.

Similarly when you cool down, do this gradually and before turning the burner off, go back to a yellow flame and continue gentle heating until carbon builds up on the glass again. That is your temperature indicator that the glass has cooled below the strain point and then you can stop heating. You can wipe the soot off easily with a paper towel.

Also try not to make the angles too sharp around the edges of the grooves - sharper angles inherently lead to stress concentration and require more time for annealing.
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