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Loose glass envelope

ashok

Member
2002-06-06 4:43 am
3RS
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.
 

ashok

Member
2002-06-06 4:43 am
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.
 

ashok

Member
2002-06-06 4:43 am
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.
 

ashok

Member
2002-06-06 4:43 am
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.