Loose glass on valve

[paulf-2007]

I have a brimar 6L6G valve with a loose glass, works perfectly but worries me. Someone mentioned acetone but I don't remember what to do with it. Be nice to fix it to the base.

[Lawrence001]

I was told to drip superglue into the gap between the glass and base, never tried it though. Is acetone the same thing?

[Patrick Dixon]

The 'valve' is the glass envelope, so really it's the base that's loose rather that the valve ;-)

Superglue should do it; when you extract the valve from the equipment try and pull it by the base because if you pull on the glass you might just break the connections to the pins.

Acetone is nail varnish remover, so it will probably dissolve the rest of the glue and make the problem worse.

[Stryder5]

I was told to drip superglue into the gap between the glass and base, never tried it though. Is acetone the same thing?

No they’re opposites superglue is a glue (sorry), acetone removes glue!

I would use superglue, it hopefully will make the valve base/glass more stable.

Gary

[walpurgis]

Superglue will probably do the job, but put low tack masking tape around the valve base and glass envelope leaving just the gap to be filled exposed. That will stop any dribbles messing things up.

[dave2010]

Avoid getting superglue on anything nearby - unless you don't care. As it happens I tried to fix a chipped mug yesterday with superglue - not great, but serviceable. Unfortunately I dripped a small amount on to a table, so I then had to look up how to remove it. Acetone / nail varnish remover seems the way to go - though I'm not sure I'll manage to do a nice job on the table top. Worth a try.

So cover any surfaces which you care about (or the missus cares about) before attempting this fix. Otherwise, the fix should work I believe.

[walpurgis]

Unfortunately I dripped a small amount on to a table.

Acetone may also remove any finish the table had.

[Hibster_2000]

Keep a cocktail stick handy when working with superglue.
Roll it between your fingers if you suspect you have any glue on them and it stops them sticking together.

[struth]

pure or near Acetone is viscious stuff and highly flammable. it can crack glass too. it melts many things too. We used it a lot; big drums of stuff I had to carry around in truck. very dodgy stuff unless careful. The stuff you get for nail polish is dilute in comparison:eyebrows:

[disarmamant]

Don’t use superglue, read this...

https://jacmusic.com/accesories/Tube-Glue/tube-glue-index.html


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[walpurgis]

Well perhaps he would say that, he's trying to sell a product.

[disarmamant]

Well perhaps he would say that, he's trying to sell a product.

Quite correct, but he’s trying to sell a product that’s fit for the purpose, and he supports his argument very well.

I have used his valve base glue on a number of loose based octal valves myself and it works very well indeed.


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[struth]

Super glues only go up to 100c or so, some can do 150c top.. Not sure how hot a valve gets...

[disarmamant]

Super glues only go up to 100c or so, some can do 150c top.. Not sure how hot a valve gets...

If you’d care to read the article there’s more to it than just the temperature the glue can withstand.


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[struth]

If you read the article there’s more to it than just the temperature the glue can withstand.


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yup i know but all bets are off temp wise with power valves as im sure they get hotter than that. The glue would break down. But yes there are a few things that could happen including glass cracking/splitting. but a signal valve may work.
if its a cheapish valve its maybe worth the try.

[dave2010]

Acetone may also remove any finish the table had.I realise that, but I'm hoping to be more careful than I was previously. Another technique might be to use a mild abrasive. I should probably - following your comment - apply acetone to another part of the table which isn't so visible, to see how it copes, and if it can withstand the acetone.

Thanks for alerting me to this and making me think again.

[Jimbo]

If the glass is loose don't you loose the vacuum in the tube therefore compromise the functionallty?:scratch:

[walpurgis]

If the glass is loose don't you loose the vacuum in the tube therefore compromise the functionallty?:scratch:

No, the base is just a support, generally fitted to larger valves. The glass valve 'bottle' is a separate sealed vessel.

[Lawrence001]

When I bought a loose valve I initially thought that but was told it didn't compromise the vacuum. However given the legs are connected to the base there must be some risk to the connections if the 2 parts separate a little. eg pulling out the glass when removing the valve so I sent it back.

[paulf-2007]

The 'valve' is the glass envelope, so really it's the base that's loose rather that the valve ;-)

Superglue should do it; when you extract the valve from the equipment try and pull it by the base because if you pull on the glass you might just break the connections to the pins.

Acetone is nail varnish remover, so it will probably dissolve the rest of the glue and make the problem worse.
I always pull valves by the base, it's the sensible thing to do.

[paulf-2007]

No they’re opposites superglue is a glue (sorry), acetone removes glue!

I would use superglue, it hopefully will make the valve base/glass more stable.

Garyok so the acetone was to remove the old glue

[Audio Al]

My opinion , its toast , They are vacuum tubes if the vacuum is lost you loose control of how the elements burn / Glow , Controlled
The vacuum tube is a glass tube that has its gas removed, creating a vacuum. Vacuum tubes contain electrodes for controlling electron flow and were used in early computers as a switch or an amplifier.

[Lawrence001]

The glass vacuum can still be airtight even if the base is loose as per an earlier post. But if a connection between the insides and the pins is lost them it is indeed toast.

[Stryder5]

ok so the acetone was to remove the old glue

I wouldn't try to remove old glue, just use new glue, whichever you decide to use.

Gary

[paulf-2007]

I've decided leave well alone, as well as it is, I'm now using the valve carefully inserted by only touching the base, obviously the vacuum is good. Just a thought would silicon hold it in place as in stop any rotating, not expecting to yank it out by the glass anyway.

[struth]

High temp resistant silicon sealant can do 260c so would probably be fine. They use it in oven glass doors

[scotty38]

You said it a couple of posts back so I’d recommend you do that - leave well alone and enjoy it while it’s working.

[dave2010]

I realise that, but I'm hoping to be more careful than I was previously. Another technique might be to use a mild abrasive. I should probably - following your comment - apply acetone to another part of the table which isn't so visible, to see how it copes, and if it can withstand the acetone.

Thanks for alerting me to this and making me think again.Good to hear that the valve is still working, though the high temperature silicone sounds as though it could be useful for a fix.

Re acetone/nail varnish remover. I bought a bottle, and applied some to the table top (not real wood - some sort of synthetic surface) - hardly any impact at all. The table top is now slightly cleaner, and the superglue is still there. I expect it'll wear in time - or I can just put my mug mat on top of it.

The table was free, anyway - and it is quite neat.

[da2222]

insert the end of wooden toothpicks in three equally spaced points between base and glass and snap them off gently. Works a treat.

[Jazid]

insert the end of wooden toothpicks in three equally spaced points between base and glass and snap them off gently. Works a treat.Might stop it rattling but only stresses the lead out wires further.

Buy Jac Music's product and have done, if its a valve worth keeping going, ie worth more than a tenner. Yes he's selling and yes it works, and no I have no axe to grind. But superglue or Araldite? Plenty of good reasons not to...

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