Author Topic: Reproduction Circlarc Tubes  (Read 2236 times)
refridgedude1841
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Re: Reproduction Circlarc Tubes « Reply #30 on: October 25, 2016, 09:48:38 PM » Author: refridgedude1841
I would do 4 if we could get the price down a little bit more ($125 ish)...at that price probably only 2.  Then again if this is a one time thing I'd probably be stupid not to get 4, as I'd have no spares if I only got 2.
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Re: Reproduction Circlarc Tubes « Reply #31 on: October 26, 2016, 02:57:21 PM » Author: DieselNut
I want to wait a bit also because there are other members who have circlarc fixtures and may can help get the quantities up.  If so, you can count me in for six.  I only want to be guaranteed they are high quality and have a decent lifespan.  It would suck to spend that much money on something that blows filaments or leaks vacuum in a short time.
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refridgedude1841
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Re: Reproduction Circlarc Tubes « Reply #32 on: October 26, 2016, 08:58:20 PM » Author: refridgedude1841
Agreed.  I know there are at least 2 other members who haven't chimed in yet (maybe you could PM them, search thru threads for circlarc posts and PM the members that haven't posted here yet? ) and there may be more. 

I would also agree I'd want some sort of guarantee of a decent lifespan w/ replacement if it failed abnormally early (like say under 100 hours or something) if I'm spending several hundred dollars I want to be able to actually use the fixture daily without fear of the tubes failing in a short time.

I want to wait a bit also because there are other members who have circlarc fixtures and may can help get the quantities up.  If so, you can count me in for six.  I only want to be guaranteed they are high quality and have a decent lifespan.  It would suck to spend that much money on something that blows filaments or leaks vacuum in a short time.

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refridgedude1841
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Re: Reproduction Circlarc Tubes « Reply #33 on: April 10, 2017, 09:48:57 PM » Author: refridgedude1841
Was there ever any more movement on this?

Agreed.  I know there are at least 2 other members who haven't chimed in yet (maybe you could PM them, search thru threads for circlarc posts and PM the members that haven't posted here yet? ) and there may be more. 

I would also agree I'd want some sort of guarantee of a decent lifespan w/ replacement if it failed abnormally early (like say under 100 hours or something) if I'm spending several hundred dollars I want to be able to actually use the fixture daily without fear of the tubes failing in a short time.

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Re: Reproduction Circlarc Tubes « Reply #34 on: April 13, 2017, 02:40:34 PM » Author: James
Somehow I missed this post when it first came up.

I agree with Ash, the most economical way to produce such a thing would be to cut an existing Circline lamp into two pieces, and reseal new electrodes into the open ends.

The tooling costs to produce a new shape of Circline lamp would be monstrous.  About a decade ago when my company was still producing Circlines we had a request to make half-circlines, like a Circlarc, for ultraviolet facial tanning units.  Instead of staring into a small table-top unit with straight tubes that only irradiate the front of the face, they would have curved around the head to give a more uniform all-around tan with less shadowing.  Technically of course this was feasible.  However it would have required new tooling to the order of around €50,000 on the BendEx machine, which bends and exhausts ordinary straight tubes.  And also something like 2000 man-hours to modify the machinery, and for lamp design, testing and release.  Because of that it never went forward.

In smaller factories with less mechanised equipment it could be easier - but then with high labour cost.

Another technique, albeit chronically slow, is to take a finished straight tube and re-shape it.  That can be done by heating the glass in a moving cylindrical oven while applying a continuous force to bend it to a curved shape.  The heating has to be very slow, if the glass becomes too hot then it sucks in under the vacuum.  There is a company in Italy that used to do that, but still costing some hundreds of € per tube. 

So if the quantity is very low I would suggest a full manual operation with no machines.  And to start with ordinary Circlines cut in half to re-use the glass, and just seal in new electrodes by manual glassblowing techniques.  That would be fairly easy, any scientific glassblower could do it.  If someone happens to know the specs of the original Circlarcs (radius of curvature, tube diameter, and lamp voltage at rated current), I may give it a go and see how easy it could be!
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Re: Reproduction Circlarc Tubes « Reply #35 on: April 13, 2017, 03:01:36 PM » Author: Lumex120
Somehow I missed this post when it first came up.

I agree with Ash, the most economical way to produce such a thing would be to cut an existing Circline lamp into two pieces, and reseal new electrodes into the open ends.

The tooling costs to produce a new shape of Circline lamp would be monstrous.  About a decade ago when my company was still producing Circlines we had a request to make half-circlines, like a Circlarc, for ultraviolet facial tanning units.  Instead of staring into a small table-top unit with straight tubes that only irradiate the front of the face, they would have curved around the head to give a more uniform all-around tan with less shadowing.  Technically of course this was feasible.  However it would have required new tooling to the order of around €50,000 on the BendEx machine, which bends and exhausts ordinary straight tubes.  And also something like 2000 man-hours to modify the machinery, and for lamp design, testing and release.  Because of that it never went forward.

In smaller factories with less mechanised equipment it could be easier - but then with high labour cost.

Another technique, albeit chronically slow, is to take a finished straight tube and re-shape it.  That can be done by heating the glass in a moving cylindrical oven while applying a continuous force to bend it to a curved shape.  The heating has to be very slow, if the glass becomes too hot then it sucks in under the vacuum.  There is a company in Italy that used to do that, but still costing some hundreds of € per tube. 

So if the quantity is very low I would suggest a full manual operation with no machines.  And to start with ordinary Circlines cut in half to re-use the glass, and just seal in new electrodes by manual glassblowing techniques.  That would be fairly easy, any scientific glassblower could do it.  If someone happens to know the specs of the original Circlarcs (radius of curvature, tube diameter, and lamp voltage at rated current), I may give it a go and see how easy it could be!
What is the name of the company you work for? Is it a well known brand?
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Re: Reproduction Circlarc Tubes « Reply #36 on: April 14, 2017, 11:46:38 AM » Author: DieselNut
The "radius" of the Circlarc is not the same as a Circline and to fit the fixture, it must be perfect, as the ends are fixed.  It looks to me like the Circlarc is an arched F15T8 tube.
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Re: Reproduction Circlarc Tubes « Reply #37 on: April 15, 2017, 05:59:34 AM » Author: James
I am working for Sylvania (Europe).

If the radius is different than any existing Circline, then it could be difficult and not cheap to get replicas made.

Did you ever try to contact Voltarc / LightTech?  They are probably one of the most flexible manufacturers to approach for small series production.  See http://www.light-sources.com/solutions/specialty-fluorescent/products/custom-lamps/

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Re: Reproduction Circlarc Tubes « Reply #38 on: April 15, 2017, 02:40:01 PM » Author: Ash
Can a close radius circline be softened and reshaped on a Metal drum form ? I'd expect less trouble than trying to bend a straight tube
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Re: Reproduction Circlarc Tubes « Reply #39 on: April 16, 2017, 04:25:38 PM » Author: James
If the metal drum is hot and the glass temperature very uniform it might work.  But if I was doing it myself I would find it easier to bend a new straight piece of glass by hand.  Many things in glassblowing you have to get right first time, corrections are often more difficult than starting again from scratch.
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Re: Reproduction Circlarc Tubes « Reply #40 on: April 20, 2017, 04:17:30 AM » Author: monkeyface
Speaking about bending straight fluorescent tubes. I have ordered a new bended tube for my Lazzurro S1 fixture. It is currently the most expensive one in the collection with a value of about €215.-
http://www.lighting-gallery.net/gallery/displayimage.php?album=533&pos=77&pid=15474
It seems that the tube was made as a standard bi pin TLD 36W/830 by Philips and then later modified by a different workshop for the intended purpose.
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refridgedude1841
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Re: Reproduction Circlarc Tubes « Reply #41 on: April 21, 2017, 10:23:49 PM » Author: refridgedude1841
I reached out to them on Facebook this week.  They didn't think they could do it unfortunately and even if they did they wanted a minimum commit of 1000 tubes.  Said the tooling would be too much for say 50 to 100 lamps.  They said they've had the request in the past too.


I am working for Sylvania (Europe).

If the radius is different than any existing Circline, then it could be difficult and not cheap to get replicas made.

Did you ever try to contact Voltarc / LightTech?  They are probably one of the most flexible manufacturers to approach for small series production.  See http://www.light-sources.com/solutions/specialty-fluorescent/products/custom-lamps/


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Re: Reproduction Circlarc Tubes « Reply #42 on: April 23, 2017, 03:19:47 PM » Author: James
Thats a pity about Lightsources.

I wish I could remember who produced the Lazurro tubes.  I can remember seeing a video of them being made at the Hannover Light Fair in 1998.  It was indeed a standard Philips tube that was modified by a small workshop in Italy.  They used a laser to detach the phosphor coating from the tube ends (or even to write clear text in the tube for custom orders), and then bent it by a special process using a travelling electric heater cylinder that gradually moved along the tube to soften the glass, while applying a force to the lamp ends to bend it.
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