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An experiment.

An experiment.

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So, as some of you may know, a few days ago in the previous haul I received some NOS Tungsram CW F40T12 tubes, that were defected from the factory, and all four developed hairline cracks along the ends. Three lost vacuum, but this one did not. I installed it in my bathroom fixture and I will see how long will it survive until enough air leaks in overtime trough the crack to distinguish the arc. Since I installed the tube (witch was Saturday) the hairline crack grew about 5mm longer than before. I'll keep you updated on it. I am genuinely interested on how long it will last.

Cleared out Pila F40T12.jpg IMG_20190313_191917.jpg Hairline crack Tungsram NOS cw f40t12.jpg Poltava LDC-36 clear end.jpg

Light Information

Light Information

Manufacturer:Tungsram
Model Reference:F33 F40T12
Electrical
Wattage:40w
Voltage:220v
Optical
Lumen Output:Moderate
Lumen Efficacy:Moderate
Color Temperature:4500k
Color Rendering Index:High
Physical/Production
Factory Location:Hungary
Fabrication Date:somewhere in early 2000s
Application/Use:For outdoor/indoor lighting

File information

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Filename:Hairline crack Tungsram NOS cw f40t12.jpg
Album name:vytautas_lamps / fluorescent tubes T8/T12
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File Size:404 KB
Date added:Mar 12, 2019
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Date Time:2019:03:12 23:34:25
DateTime Original:2019:03:12 18:58:11
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rjluna2
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Robert


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Mar 12, 2019 at 06:36 PM Author: rjluna2
Probably poor annealing

Pretty, please no more Chinese failure.

Silverliner
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Verd a ray classic.


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Mar 13, 2019 at 01:41 AM Author: Silverliner
Put tape on the crack?

May all the great lighting technologies have their place in history.

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Mar 13, 2019 at 05:09 AM Author: Proteus
Oh I hate when tubes do that... Like some Thorn/Atlas tube if you want to take them out of a box and you just recognize that there's nothing but the endcap and the electrode in your hand...
vytautas_lamps
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My idol is Mylene Farmer, deal with it.


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Mar 13, 2019 at 07:19 AM Author: vytautas_lamps

Put tape on the crack?

I don't know if it will help much. Let's just see what happens

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 ;

vytautas_lamps
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My idol is Mylene Farmer, deal with it.


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Mar 13, 2019 at 07:23 AM Author: vytautas_lamps

Oh I hate when tubes do that... Like some Thorn/Atlas tube if you want to take them out of a box and you just recognize that there's nothing but the endcap and the electrode in your hand...

OOOOhhh. . . that sucks so badly! I absolutely hate hate hate when that happens. For someone who knows nothing about lamps that would be nothing, but for a tube collector it can really ruin your day, and mess you up emotionally. I once had two working soviet F80T12 NOS tubes in my collection that my grandpa have me, and they were so cool a,d dear to my heart. I once tried to take them of the shelf and I grabbed one end by the endcap and I just hear snap as I start lifting, and the cathode is resting in my palm. It messed me up, I was crying like crazy. Of course I was a kid back then, but still, today it also sucks to see a NOS tube go like that. Really ruins my day.

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 ;

Lightingguy1994
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Mar 13, 2019 at 11:50 AM Author: Lightingguy1994
The tube will fail soon. The temperature cycles from being off and on over time will grow the crack. You may be able to put some clear silicone all around and see how that holds up. It may be able to hold in the vacuum a bit longer even if the crack goes all around
vytautas_lamps
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My idol is Mylene Farmer, deal with it.


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Mar 17, 2019 at 09:16 AM Author: vytautas_lamps
Update. The cracked tube had some problems starting this morning 2019-03-17. Starter flashed it solidly for 15 - 20 seconds until arc ignited. Probably air that is slowly creepin' trough the crack is reaching arc distinguishing equilibrium, bit by bit. I will update you if something unusual happens again, or if the tube seizes to ignite an arc. I will probably film a video of it smashing in my yard and upload it to youtube, idk what else to do with it.

btw the tube was installed in 2019-03-08

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 ;

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Mar 17, 2019 at 11:21 AM Author: Proteus
Would be interesting to warch it fail in 24/7 usage! When it sucks air inside bit by bit, the arc should just change until it goes out one day.
vytautas_lamps
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My idol is Mylene Farmer, deal with it.


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Mar 17, 2019 at 11:25 AM Author: vytautas_lamps
I could do a livestream of it.. Hmmm will think about it.

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 ;

vytautas_lamps
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My idol is Mylene Farmer, deal with it.


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Mar 19, 2019 at 02:18 AM Author: vytautas_lamps
UPDATE: The tube this morning (2 hours ago when I woke up) failed to start on preheat. Flashed for a solid minute until I decided it was donzoed. On IS ballasts still starts, but is abnormally bright and the cathodes blackened in front of my eyes. I think emitter compensated for air inside the tube and sputtered the cathodes to near EOL state. Welp, she dead. I'll wait for more air to leak inside and I will fry it on MOT. Wait for a upcoming video

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 ;

Ash
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Mar 19, 2019 at 02:53 PM Author: Ash
Got any more of them ? I would be interested to add a voltmeter to measure the arc voltage while the lamp lasted. (with suitable protections to prevent damage to it at lamp starting)
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