Hello!
First post! This is really a great forum and site, i am so happy to have found it!

I have got a big, nice, craptacular 250W mercury vapor lamp manufactured in China by Osram using "GERMAN TECHNOLOGY" in 2000. The only problem is that the E40 base has come loose from the bulb. The base does still make good electrical connection but you could not screw it into a socket without causing damage to the bulb. The cement that used to hold the cap in place is crackling and falls out when the bulb is handled.

Is there any way to readhere the cap back to the bulb in any way or should i just retire this bulb to do decoration service? It seems such a waste as the bulb has got pretty much no use at all.

/Edmund

best thing to do is unsolder the lamp base clean out old adheasive and try to find Glassbond lamp cement.
i think u cure it by heating the cap up.

What about a loose endcap?
Or a damaged pin on a fluorescent?

I have Used Donner End caps from EOL lamps and use hi temp glue sticks for glue guns. get end cap ready put on and quickly shoot hot glue in end cap push cap on to the lamp. Then solder your wires into the pins of end caps.  but  I carefully remove old endcap with a utilty knife and pair of dike.  I rather use old westy black-ender end caps when lamp EOLs i just recover my end caps for next lamp. i mod my slimeline lamp esp 6 footer
that can only run on red and blue leads on the F40  ballast. 

best thing to do is unsolder the lamp base clean out old adheasive and try to find Glassbond lamp cement.
i think u cure it by heating the cap up.

Yes, i am aware of Glassbond Cement. The problem is that you cant really buy the stuff, the manufacturer seems to only sell it to bigger lamp manufacturers and from what i understand the shelf life of the unused cement powder is quite short. I have been looking at high temperature epoxy and silicone but these does a MAXIMUM of about 200 degrees celcius. This is waaaay too low for a 250W mercury bulb.

When it comes to a flourescent tube end cap i guess it would be no problem to use a high temperature epoxy. I know there are also some silicon adhesives around that can tolerate high temperatures.
https://www.biltema.se/bygg/kemikalier/silikon/silikon-hogtemperatur-2000017141
This one from a Swedish retailer can stand up to 250 degrees celcius. No problem at all for most flourescent tubes as they dont really get that warm as long as they are fairly low wattage.

I have successfully used Gorilla Glue to repair loose caps. Perhaps not the first thing you'd think of, but someone told me it worked and I thought it was worth a try. It worked fine after leaving the lamp for 24 hours. Might be a little cheaper than specialist stuff..?

I have successfully used Gorilla Glue to repair loose caps. Perhaps not the first thing you'd think of, but someone told me it worked and I thought it was worth a try. It worked fine after leaving the lamp for 24 hours. Might be a little cheaper than specialist stuff..?

I have heard about Gorilla glue being very temperature resistant but they wont disclose just how much temperature it can stand. Typical marketeering bulls*it.

I have heard about Gorilla glue being very temperature resistant but they wont disclose just how much temperature it can stand. Typical marketeering bulls*it.

Well so far it's withstood the heat of a 250W MA/V lamp running for 5 hours, not sure what temperature it gets to off hand, I'll measure it next time I run the lamp up.

Well so far it's withstood the heat of a 250W MA/V lamp running for 5 hours, not sure what temperature it gets to off hand, I'll measure it next time I run the lamp up.

Well that is great to hear. This bulb in particular i just super glued together as it only use it for display. I'll get my hands on some Gorilla glue and keep it on hand. Could you send a link of what specific Gorilla Glue your using?

Well that is great to hear. This bulb in particular i just super glued together as it only use it for display. I'll get my hands on some Gorilla glue and keep it on hand. Could you send a link of what specific Gorilla Glue your using?

This is the stuff I use (sorry, photo won't rotate..!)