Loose glass envelope

ashok · 9th August 2002, 08:19 AM

I have several Russian NOS tubes. The 6SL7 and 6SN7 . Many of them have glass envelopes that are loose. If they are twisted while insertion into the socket there is a danger that the leads in the base may get damaged or even come off. Not to mention microphony due to a wobbly glass envelope.
Does anyone know how this can be glued back reliably. I was thinking of using Instant Glue or the standard two tubed Araldite. Note that the glass envelope does not come out of the base but is free to rotate a little bit.
Thanks.

Vivek · 9th August 2002, 08:40 AM

Hi Ashok,
Where can I buy valves in India?
Vivek

ashok · 9th August 2002, 12:48 PM

Vivek,you should be telling me where tubes are available. Bangalore was the place where BEL made tubes in collaboration with Mullard. So there must be lots of NOS tubes lying around. I did try to locate it myself but could not. Lalwani Electronics on Ritchie Street in Chennai has lots of tubes . I found that most were never even mentioned on any forum on the web. Some tubes also seem to be UOS ( used old stock !) . No guarantee if they will work well. My experience is that performance varies wildly from piece to piece. Better buy new tubes from Singapore or any nearby country.

Vivek · 9th August 2002, 01:08 PM

Hi Ashok,
If BEL was making it I should try looking around. But importing them is a real pain with the customs and import duties.

Vivek

Duo · 9th August 2002, 06:37 PM

Hi Ashok, I have had many tubes with that problem, usually any old glue works fine for that. Epoxy is nice and also, white glue works, but it's hard to keep the glue job clean so it takes some practice to get it right. I hope this helps...

ashok · 11th August 2002, 03:36 AM

Hi Duo,
I checked the net and found that they do not recommend instant glue for glass. The note said that it would come loose in about a weeks time. So I guess epoxy is best. The standard version generally has better specs than the quick set version. Thanks for your suggestion. I shall glue a few tubes with it .
What was "white glue" ?
Thanks.
I did use instant glue yesterday on two tubes. If it comes apart I will post a message.

planet10 · 11th August 2002, 04:22 AM

Quote:

Originally posted by ashok
What was "white glue" ?

PVA wood glue.

dave

ashok · 11th August 2002, 06:31 AM

Thanks Dave.
I will be using epoxy as it is much stronger when set. PVA tends to be soft and I think it might not be able to with stand the heat.

I thought that the 'white glue' was some other type of epoxy that sets hard. I have seen some of this applied in some machines and they are quite hard when scratched. I wonder what that is .
Thanks.

9th August 2002, 08:19 AM	#1
ashok diyAudio Member Join Date: Jun 2002 Location: 3RS	Loose glass envelope I have several Russian NOS tubes. The 6SL7 and 6SN7 . Many of them have glass envelopes that are loose. If they are twisted while insertion into the socket there is a danger that the leads in the base may get damaged or even come off. Not to mention microphony due to a wobbly glass envelope. Does anyone know how this can be glued back reliably. I was thinking of using Instant Glue or the standard two tubed Araldite. Note that the glass envelope does not come out of the base but is free to rotate a little bit. Thanks. __________________ AM

9th August 2002, 12:48 PM	#3
ashok diyAudio Member Join Date: Jun 2002 Location: 3RS	Tubes Vivek,you should be telling me where tubes are available. Bangalore was the place where BEL made tubes in collaboration with Mullard. So there must be lots of NOS tubes lying around. I did try to locate it myself but could not. Lalwani Electronics on Ritchie Street in Chennai has lots of tubes . I found that most were never even mentioned on any forum on the web. Some tubes also seem to be UOS ( used old stock !) . No guarantee if they will work well. My experience is that performance varies wildly from piece to piece. Better buy new tubes from Singapore or any nearby country. __________________ AM

9th August 2002, 06:37 PM	#5
Duo diyAudio Member Join Date: Jun 2002 Location: Victoria, BC, Canada	Hi Ashok, I have had many tubes with that problem, usually any old glue works fine for that. Epoxy is nice and also, white glue works, but it's hard to keep the glue job clean so it takes some practice to get it right. I hope this helps... __________________ -- Duo, W1ngs, VA7MON, and lesser known handles. -- -- http://www.w1ngselectronics.com -- My Work and Projects --

11th August 2002, 03:36 AM	#6
ashok diyAudio Member Join Date: Jun 2002 Location: 3RS	Glue for tubes. Hi Duo, I checked the net and found that they do not recommend instant glue for glass. The note said that it would come loose in about a weeks time. So I guess epoxy is best. The standard version generally has better specs than the quick set version. Thanks for your suggestion. I shall glue a few tubes with it . What was "white glue" ? Thanks. I did use instant glue yesterday on two tubes. If it comes apart I will post a message. __________________ AM

11th August 2002, 06:31 AM	#8
ashok diyAudio Member Join Date: Jun 2002 Location: 3RS	White glue Thanks Dave. I will be using epoxy as it is much stronger when set. PVA tends to be soft and I think it might not be able to with stand the heat. I thought that the 'white glue' was some other type of epoxy that sets hard. I have seen some of this applied in some machines and they are quite hard when scratched. I wonder what that is . Thanks. __________________ AM

9th August 2002, 08:40 AM	#2
Vivek diyAudio Member Join Date: Nov 2000 Location: Bangalore, India	Hi Ashok, Where can I buy valves in India? Vivek

9th August 2002, 01:08 PM	#4
Vivek diyAudio Member Join Date: Nov 2000 Location: Bangalore, India	Hi Ashok, If BEL was making it I should try looking around. But importing them is a real pain with the customs and import duties. Vivek

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