Old Bulb Repair!

[Nick D.]

Hello all, I'm back... to tackle my first old bulb repair!  I bought the pictured bulb at an old junk shop for $1 (rip-off?  ) with a very badly damaged base which I removed and threw away. (sorry, no pic)

One of the lead-in wires is still in place but the other has broken off deep inside the stem of the bulb.  I am, however, easily able to light the bulb by means of a sewing needle poked up inside the stem. My question is this - has anyone ever attempted a similar (or identical?) repair, and do you have some tips to offer? 

[Tim]

This topic has been raised a few times here.  If you search through the forums you should be able to find some threads discussing re-basing bulbs and a description of the compound used to secure the base to the bulb, but I don?t think such a compound is readily available.  If I remember correctly, it?s not a simple process preparing the compound.

Let us know how you make out with your project.

[Nick D.]

This topic has been raised a few times here.  If you search through the forums you should be able to find some threads discussing re-basing bulbs and a description of the compound used to secure the base to the bulb, but I don?t think such a compound is readily available.  If I remember correctly, it?s not a simple process preparing the compound.

Let us know how you make out with your project.

Thanks for the suggestions, Tim. I haven't found anything pertaining to base repair but that's perfectly OK since I alreadly have a plan worked out. The base compound isn't a problem either. I'm going to use a carbide pen to rough up  the glass covered by the base (or maybe not, I'll have to experiment first.) to get the glue to stick that I'll be using to fill the base. My "filler compound" will be PC-11 with some sand added just to save some of the glue.

The only challenge I see is going to be getting a wire poked up and set in place inside the bulb stem...

[Tim]

Here's the most recent thread with a good description of the base cement used at the factory:

http://bulbcollector.com/forum/index.php?topic=1137.0

Keep us posted on your progress...

[Nick D.]

Done!  (yes, already )

The PC-11 was a smashing success!!! I didn't have to do any surface prep, combine any mixtures or anything!!!

I was really nervous to see how the needle was going to work but it did so quite beautifully... after I got the electrodes epoxied and set, (just 1/2 hour) it was then time to attach the base and solder the connections.

I'll give a full, detailed explanation later (tomorrow) but for now...... PICS! 

[Tim]

Well, that was quick - nice work!

Tell me more about this "PC-11" - is this an epoxy resin?  What's the cure time?  I wonder how it holds up to the heat generated from the hot carbon filament in your bulb?  Is the color gray, or more on the "white" end of the color spectrum?  I also wonder if it comes in a color more natural to that used by the bulb manufacturers.

I'll stop asking questions now 

[Nick D.]

Well, that was quick - nice work!

Tell me more about this "PC-11" - is this an epoxy resin?

Yes. Its a two part marine-grade epoxy for all kind of uses - it is guaranteed to bond glass, metal, wood, ceramics and most plastics. The warmer and drier it is the faster it will cure, however it can even cure underwater!

[Chris Kocsis]

PC-11 can stand up to 200 degrees F, according to the mfr's web site: http://www.pcepoxy.com/pastepoxies/pastepc11.asp
They also make one called PC Fahrenheit that goes to 500 degrees F.

How hot can the base of a carbon (or other) bulb get?

Chris

[Nick D.]

Here's the bulb installed in a (period?) all-brass wall fixture.  Can anyone roughly date the bulb? When did they stop making double-hairpin style filaments?

[Chris Kocsis]

If the bulb was exhausted through the tip, it probably isn't much later than 1921.  If it was exhausted through the stem (which will have a small hole below the press, if that is the case), then it was made after that time.  Such bulbs are still being made today, but mostly without the tip.  If stem-exhausted, chances are it's from the late 20s.