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    Vacuum Tube Keyway Replacement Saver Fix Repair Broken Center Guide-Post

    aguaazul
    aguaazul

    Posts : 112
    Join date : 2012-07-08
    Age : 59
    Location : Livermore, CA

    Vacuum Tube Keyway Replacement Saver Fix Repair Broken Center Guide-Post Empty Vacuum Tube Keyway Replacement Saver Fix Repair Broken Center Guide-Post

    Post by aguaazul on Fri Mar 01, 2019 3:19 am

    I pulled out a 6SN7 EH tube the other day and noticed that the Keyway was left in the socket.
    I found these:

    8 Octal Vacuum Tube Keyway Replacement Saver Fix Repair Broken Center Guide-Post

    They say:  "Put some silicon glue in between the base and saver, let it dry and wipe of the excess glue and you have a tube almost good as new."

    Then I see this special tube base glue here:

    Tube Base Glue

    Any thoughts on the best / cheapest adhesive for the job?

    Thanks,

    Bluewater
    Peter W.
    Peter W.

    Posts : 1340
    Join date : 2016-08-07
    Location : Melrose Park, PA

    Vacuum Tube Keyway Replacement Saver Fix Repair Broken Center Guide-Post Empty Re: Vacuum Tube Keyway Replacement Saver Fix Repair Broken Center Guide-Post

    Post by Peter W. on Fri Mar 01, 2019 9:07 am

    aguaazul wrote:I pulled out a 6SN7 EH tube the other day and noticed that the Keyway was left in the socket.
    I found these:

    8 Octal Vacuum Tube Keyway Replacement Saver Fix Repair Broken Center Guide-Post

    They say:  "Put some silicon glue in between the base and saver, let it dry and wipe of the excess glue and you have a tube almost good as new."

    Then I see this special tube base glue here:

    Tube Base Glue

    Any thoughts on the best / cheapest adhesive for the job?

    Thanks,

    Bluewater

    I have used clear JB Weld in the past - and it does nicely. The 5-minute variety sets up quickly enough to be convenient, but is strong enough under those conditions to be permanent.

    NOTE AND WARNING: If one has a tube where the glass envelope is loose within the bakelite (or other) base, DO NOT, under any conditions, ever use superglue to re-set the envelope in the base. It is too strong and too rigid such that under the heating/cooling conditions it will cause fractures to the envelope, or simply crack loose again. Sadly, it could go either way. Whatever glue is used should have some flex to it when cured - and one of the softer epoxies comes to mind. There is also an electronics-grade RTV silicon that will do the trick.

    NOTE: Standard RTV silicon releases acetic acid in the curing process (active ingredient in vinegar), which really does like to react with copper and/or copper compounds. Not a good thing. A blob of the stuff will eat right through a PCB trace in a remarkably short period of time.
    aguaazul
    aguaazul

    Posts : 112
    Join date : 2012-07-08
    Age : 59
    Location : Livermore, CA

    Vacuum Tube Keyway Replacement Saver Fix Repair Broken Center Guide-Post Empty Re: Vacuum Tube Keyway Replacement Saver Fix Repair Broken Center Guide-Post

    Post by aguaazul on Fri Mar 01, 2019 11:41 am

    I have JB Weld Epoxy in stock, but it says on the back that it's good up till 240ºF.  
    The ol' interweb say's:

    Once J-B Weld ClearWeld has cured it has a tensile strength of 4400 PSI and can tolerate temperatures of up to 148C/300ºF.

    Then there is JB Extreme Heat...

    J-B Weld Extreme Heat is formulated to allow for repairs to iron, steel and metal in high temperature environments (2400°F / 1300°C). When fully cured, this metallic compound can be drilled, machined or sanded.

    I ordered the ClearWeld. Thanks Peter.

    Bluewater
    sKiZo
    sKiZo

    Posts : 1532
    Join date : 2013-04-01
    Location : Michigan USA

    Vacuum Tube Keyway Replacement Saver Fix Repair Broken Center Guide-Post Empty Re: Vacuum Tube Keyway Replacement Saver Fix Repair Broken Center Guide-Post

    Post by sKiZo on Fri Mar 01, 2019 7:45 pm

    If it's a tube that's near and dear to your ear, I'd just dot the base and socket with a fine tip sharpie and match those when inserting, otherwise toss it. If you do decide to repair, maybe put a bit of dialectic grease on the key to avoid having it bind or set into the socket.
    aguaazul
    aguaazul

    Posts : 112
    Join date : 2012-07-08
    Age : 59
    Location : Livermore, CA

    Vacuum Tube Keyway Replacement Saver Fix Repair Broken Center Guide-Post Empty Re: Vacuum Tube Keyway Replacement Saver Fix Repair Broken Center Guide-Post

    Post by aguaazul on Sat Mar 02, 2019 12:05 am

    sKiZo wrote:If it's a tube that's near and dear to your ear, I'd just dot the base and socket with a fine tip sharpie and match those when inserting, otherwise toss it. If you do decide to repair, maybe put a bit of dialectic grease on the key to avoid having it bind or set into the socket.

    sKizo,
    In this instance, it's replaceable, ordered another one already. It's the exercise of saving one that I'm going through.

    I learned that I need to be a little lighter on the ol' hand pulling them out.

    We just took possession of some really nice tubes that are closer to near & dear.
    If I cracked the base of one of the PSVane CV-181's... well I'll be happy to know I can fix em.


    Cheers,

    Bluewater

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