DIY Audio Projects Forum

How to disassemble a tube?
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Author:  Soundbrigade [ 21 Apr 2017, 15:34 ]
Post subject:  How to disassemble a tube?

I have gotten idea, inspired by an USB-memory housen in an old tube-tube. What I want to do is to take a tube, most suitable is an octal one or other type that has a plastic "bottom", separate the bottom from the glass, open up the glas from the bottom and remove the metal junk inside and throw in something else and glue the glass to the bottom.
I have some octal tube I can spare and even a pair of Russian 807s.
What I am trying to figure out is how to open up the glass tube, not braking it too much.
Any ideas?

Author:  Suncalc [ 21 Apr 2017, 20:27 ]
Post subject:  Re: How to disassemble a tube?

Here is what I would do with an octal (or similarly constructed) tube.

1) Heat the pins and remove the plastic base from the tube. Note that pins have to be heated evenly while not melting the center guide. I'm not sure how to do this but it should be possible because I've seen instances where bases with broken guide pins are replaced. Maybe just cut the base off with a Dremel type cutting wheel and replace it with a new one.

2) Now that the base is removed I would use the same Dremel tool with a diamond cutoff wheel to cut through the tip of the evacuation tube at the base of the tube letting air in to equalize the pressure. Now that the pressure is equalized, I'd use the diamond cutoff wheel to carefully sever the bottom of the tube below the line where top of the plastic base sits. You could make a jig that holds the tool steady and then has a couple of V-blocks to rotate the tube against the edge of the miniature cutoff wheel. This would minimize breakage.

3) When cut through all the way around, carefully remove the base pins and the internals of the tube. Cut the pins above the base to remove the internals. Leave enough length to solder something new to the pins.

Replace the internals with whatever you like. You could even put some solid state electronics in the tube connected to the pins in the base. When it was glued back together a custom wired socket would provide connectivity. You could have flashing LEDs, little motors moving things, anything you wanted. And it wold still look like an old vacuum tube. Great idea!

Author:  Soundbrigade [ 22 Apr 2017, 09:15 ]
Post subject:  Re: How to disassemble a tube?

Sounds like a sound advice. I never gave the tube a chance to adjust to room pressure and maybe that resulted in too much of the glass breaking.
Will try that when I get home (I am in Prague right now).

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