Question about chipped or damaged exhaust tips.

[gutfinski]

I have several early bulbs, including some fairly rare ones, which have the exhaust tips chipped or otherwise damaged but not so much as to allow the bulb to lose its vacuum or gas.? I do have a technique I have used on some chipped bulbs to "fire polish" the tip with a small torch.? This tends to smooth over the chip and when carefully done, makes the tip appear original and undamaged.?

A couple of questions:

First, what do people in this forum think of this idea?? Is it unethical to repair a bulb tip in this fashion?

The other, how much does a chipped tip diminish the collector's desirability of a bulb provided the filament is intact and the bulb operates properly?

Any comments would be appreciated.

Roy C. Gutfinski
Pittston, Maine

[Chris W. Millinship]

I don`t know about anyone else but I have never seen a slightly chipped tip as much concern if that damage does not compromise the vacuum/gas-fill. I know in the world of "mainstream" antiques, chips on glassware usually adversely affects their value, but I have always seen the concern over chipped light bulb exhaust tips as being the same as open filaments. In other words if you knock the tip off from a bulb and it opens it to the air, it will no longer work and the bulb would be worth less to a collector. But if all it does is splinter a small bit of glass from the very end and leave a rough edge, but the bulb will still light perfectly well, I can`t see that harming the value to any significant effect.

The only exception I think would be the comemmorative anniversary lamps, particuarly the General Electric Edison 50th Anniversary one, where the tip is purely decorative but an essential part of the design of those lamps which are first and foremost designed to look the part. Also lamps where the manufacturing technique relating to the way the tip was finished off was particuarly unusual or distinctive, though examples escape me right now


As for repair, well don`t forget the Red Bulb Repair that was done by James Hooker as a demonstration of whether it could be done (it could), even if that was repairing an open filament not just a damaged tip. I know James has re-evacuated and repaired open tips on one or two other bulbs too while at Swansea University, but now works in Belgium and I`m not sure if the resources and materials are so avaliable now, let alone the time. I don`t get involved in "ethics" as we all differ in our beliefs, but I guess it counts the same as restoration to antique furniture, etc. Sometimes it`s best to leave it alone to show its age and history, other times it is desirable to repair and restore something badly worn or damaged. It would then have been returned to near-as-original condition, but it is still not completely original because there are newer replacement parts in some places, etc. Worth more than the un-restored item but less than one that never needed restoration.

If it helped to bring a fairly rare early bulb back to working condition where it could be seen shining again, I`d say it could be worth doing if the right person with the necessary skill performed the work and did not risk losing the whole piece completely in the process. I risked losing my red one if things did not work out, thankfully in that case it went well and now it works like new. Unfortunately every one is different and success is never guaranteed. But purely for cosmetic reasons if otherwise working, especially for the very rare ones, personally I would not be willing to take the risk of losing them completely.

[gutfinski]

Thank you for your advice and information, Chris.? It reminds me of something I learned a couple of years ago when I bought a tipped bulb which should have had a tungsten cage filament and was etched "Mazda" but in fact had a carbon filament.? It turned out the bulb was one of many bulbs re-manufactured early in the 20th century.? A separate industry developed from the practice of cutting the top off a bulb with a blown filament, reattaching a new looped carbon filament, exhausting the air inside the bulb, and finally re-sealing the top and creating a new exhaust tip.? This is how Sylvania got started in the bulb business.? It was a labor-intensive process but the labor cost must have been less than the cost of manufacturing a complete new bulb with base, etc.

I will probably leave the few bulbs I have with chipped tips as they are since the seals have not been breached and the filaments are intact.? They do light (I use a reduced voltage) and the chips can remain as evidence of "good, honest wear."

Roy

[James]

Hi Chris, Roy,

Yes I am still around and indeed have the resources at Sylvania to do this kind of thing!  If the lamp is airtight then I don't think its worth the risk or effort.  But if it is something very special and irreplaceable, and the tip is completely gone, send me an email with a photo and I am happy to consider it.  I've had an old radio valve from another collector sitting on my desk for a couple of months though that I haven't yet got around to repairing, so I can't promise a quick service!  But on the whole so long as the filament is also intact, lamps are pretty easy for me to retubulate and pump out again.

Best regards,

James