Author Topic: Cutting glass without bulb envelope breaking???  (Read 274 times)
takemorepills
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Cutting glass without bulb envelope breaking??? « on: January 15, 2022, 11:54:05 AM » Author: takemorepills
I've been wondering if there's a way to "save" old bulbs by cutting them open, generally at the base, and removing the failed filament and other bits so I can insert an LED retrofit PCB into them?

From my experience, bulb envelops seem to become unstable and fragile once a part of their original envelope is missing.

I have a desperate idea, if I could cleanly cut the glass at the bulb base without inducing additional stress, might the envelope be stable enough to be reused?

I am scheming to see if it is possible to "save" failed bulbs that are unique, such as inside-coat Christmas bulbs (may be toxic?) unique bulb shapes, Lumilines, etc.

Not too concerned about  the economics of it, more about the feasibility. Making LED inserts for bulbs is not a problem for me. I just have no experience cutting bulb envelops.....
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Rommie
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Re: Cutting glass without bulb envelope breaking??? « Reply #1 on: January 15, 2022, 12:18:15 PM » Author: Rommie
It's unlikely. The inside surface of a lamp envelope is incredibly fragile; it's why so many breakages occur when parts of the inner construction such as a discharge lamp mounting frame make contact with the inside of the glass if a package is roughly handled in shipping  :-\
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Ria (aka Rommie) in Aberdeen
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takemorepills
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Re: Cutting glass without bulb envelope breaking??? « Reply #2 on: January 15, 2022, 12:34:13 PM » Author: takemorepills
Maybe I should just get a diamond cutting blade for my Dremel and see what happens..... I mean, the bulbs are already dead...
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Rommie
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Re: Cutting glass without bulb envelope breaking??? « Reply #3 on: January 15, 2022, 12:36:46 PM » Author: Rommie
Wouldn't hurt, it'll either work or it won't  :-\
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Ria (aka Rommie) in Aberdeen
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Alex
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Re: Cutting glass without bulb envelope breaking??? « Reply #4 on: January 16, 2022, 02:03:43 AM » Author: Alex
Maybe I should just get a diamond cutting blade for my Dremel and see what happens..... I mean, the bulbs are already dead...

Hello,

Thats a good idea, you need small dreml cutter wich are diamond coated in the design similar to a small cuttoff disc. Then you remove the lamp base. If you do not want to destroy it mecanicly you can heat it up, and the cement should loos it glueing properties. As next you brake away the sealing nipple and cut of the wires leadin in the stemm. Now you put your cutting disc on it, in a way that the screw wich fastens it to the dreml shaft is in the stem cavity. You grind with the surface of the disc slowly the stem out, wich can then be extraxted in one piece. So unlike with angle grinder you do not cut with far edge of the tool but with its side. Cutting it with the tools edge will likely destroy the glas. Water cooling(By a wet brush for example), and only light pressure.


Another method is, you start with a class cutter and score a line around the lamp, then you put a piece of adequately seized iron wire around it (1 loop) wich is then connected to an adequate source of electricity. The wire will start glowing and make a clear brake-line along the scared line. The correct wire size and electricity sources must be found out by experiment, as i do not recall what i did use. I used that method for opening christmal light bulbs, to convert the to led. Note, here a agin it is essential that the vacuum is removed before opening the lamp.


Best regards

Alex
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takemorepills
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Re: Cutting glass without bulb envelope breaking??? « Reply #5 on: January 16, 2022, 10:34:17 AM » Author: takemorepills
Alex,

Thanks for the pointers! All makes sense and seems possible for me to attempt.
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wide-lite 1000
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Re: Cutting glass without bulb envelope breaking??? « Reply #6 on: January 16, 2022, 11:57:13 AM » Author: wide-lite 1000
Talk to Joe Maurath Jr. He's done a bunch of the conversions you're referring to !
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