Hi tube friends. I got question. Have been playing simple kt88 se amp, great sound, having fun swapping various kt88 brands. However, i noticed one tube is slightly loose between the glass and base.
Any remedy?
Any remedy?
Natronwasserglas translates as Soda water glass!
For a glass to metal bond try a UV curable adhesive which allows for the different thermal expansions of the two materials.
https://www.antala.uk/products/adhe...ves/permabond-uv610-adhesive-for-glass-metal/
For a glass to metal bond try a UV curable adhesive which allows for the different thermal expansions of the two materials.
https://www.antala.uk/products/adhe...ves/permabond-uv610-adhesive-for-glass-metal/
Don't know if it's the same stuff, but spin-on glass is common in the semiconductor manufacturing industry. That could work.
I bet clear nail polish would work too. You can always dilute it with acetone to make it flow better between the base and the glass.
The UV curable adhesive is a good option as well.
Tom
I bet clear nail polish would work too. You can always dilute it with acetone to make it flow better between the base and the glass.
The UV curable adhesive is a good option as well.
Tom
Cyanoacrylate. AKA Krazy Glue.
Yesterday, I used it to glue a loose pin on an IEC power connector.
Yesterday, I used it to glue a loose pin on an IEC power connector.
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The liquid glass or muffler paste is probably closest to the original stuff. Be careful using super glue as many common types have a specified service temp below 100C. Surface contamination is probably why the original bond failed and fixing that is probably your biggest problem.
I don't find the base gets that hot in my experience. And the glue I use is spec'd to 135°C 🙂
I also have some old RCA tubes that someone repaired with yellow ABS pipe cement. Still holding fine 20 years later.
I also have some old RCA tubes that someone repaired with yellow ABS pipe cement. Still holding fine 20 years later.
Liquid glass will work for a time, but it reacts with the ambient CO2 and slowly disintegrates. Ideally, you would need the original phenolic goop, but it is not available in DIY format.
The next best thing would be urea/formaldehyde glue, it is still available if you look hard enough.
There are "irregular" options possible: for example the putty used to repair cast-iron stoves or heater plates.
Cyanoacrylates and most of plastic resins do not behave well under high heat conditions
The next best thing would be urea/formaldehyde glue, it is still available if you look hard enough.
There are "irregular" options possible: for example the putty used to repair cast-iron stoves or heater plates.
Cyanoacrylates and most of plastic resins do not behave well under high heat conditions
Pretty sure I came across a post some time ago where someone used JBWeld. If the tube in question isn't some super exotic GEC, then you're free to experiment.
jeff
jeff
I think for tube glass bulbs you need something that's more of a filler than Krazy Glue.
Jan
You apply it to the top of the base and let it run into the void. Reapply several times to build thickness, or use a gel version.
It's because of these loose base issues that I always take the tube out by the base instead of pulling the glass.
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I use JB Weld for countless things, I'm betting anything that would hold the crap out of it epoxy can take the heat, the gray stuff. The high temp version is for automotive or maybe on your grill. The regular gray JB Weld is fine, you get about 10 minutes of working time so have toothpicks, paper plates, ice cream sticks, paper towels handy at the outset to clean off the excess. You will only get one chance to get it down deep in whatever crevece you have, leave it still and in 24 hours it will be permanent.
Same stuff, US vendor:
http://tubesusa.com/ELtubes.html
Tube Base Glue to repair loose tube bases.
$32.00 per bottle
To order: info@tubesusa.com
or call (516) 902-3334
I just did four tubes this afternoon that had slightly loose bases. I used Krazy glue and let it "bleed" into the crack between the base and the glass. It worked very well. I have not tried the tubes in sockets yet. I suspect they will be fine. I used a mini tube of glue.
I hope this helps
I hope this helps
I have practical experience on adhesives subject both to high temperature and mechanicañ stres, because I wind my own voice oils for abused Guitar/PA speakers.
First what does not work (in real use I mean, not while still cold and just applied)
* nitro type lacquer (include nail enamel into that): weakens and starts dehydrating above 90C, bubbles from 100C up , then toasts (visibly browns) cracks and disintegrates and later catches fire.
also adheres very weakly to non porous surfaces such as glass.
* cyano/krazy glue, about same, maybe stands 10C more at each stage, not enough.
Usable:
* Silastic and similar: very good, adheres VERY well to glass (You have to remove it with a sharp razor blade, go figure) so mu8ch so that it´s used to make and seal fish tanks, ec, stands 400C and there are a couple improved versions, but regular is already good enough.
Only "problem" is it´slightly elastic, but no big deal to keep glass and socket together.
You must degrease surfaces VERY well.
* Industrial Epoxy, the kind that cures overnight
Rigid, adheres reasonably well with proper degreasing, stands 250C which is more than enough there.
Pick your poison 😉
First what does not work (in real use I mean, not while still cold and just applied)
* nitro type lacquer (include nail enamel into that): weakens and starts dehydrating above 90C, bubbles from 100C up , then toasts (visibly browns) cracks and disintegrates and later catches fire.
also adheres very weakly to non porous surfaces such as glass.
* cyano/krazy glue, about same, maybe stands 10C more at each stage, not enough.
Usable:
* Silastic and similar: very good, adheres VERY well to glass (You have to remove it with a sharp razor blade, go figure) so mu8ch so that it´s used to make and seal fish tanks, ec, stands 400C and there are a couple improved versions, but regular is already good enough.
Only "problem" is it´slightly elastic, but no big deal to keep glass and socket together.
You must degrease surfaces VERY well.
* Industrial Epoxy, the kind that cures overnight
Rigid, adheres reasonably well with proper degreasing, stands 250C which is more than enough there.
Pick your poison 😉