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Problems using CA glue for JBL reconing

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  • Problems using CA glue for JBL reconing

    I'm doing my first solo JBL D120F recones, and everything has been going fine with one exception: the Loctite 410 black cyanoacrylate glue that a lot of people recommend these days for doing the very visible bead around the aluminum dust cap.

    I'm kind of new to using CA glues for this kind of thing, so I decided to do some practice runs to get a feel for how it applies. The problem is that, sometimes, this glue develops a mottled grey skin rather than drying smooth, shiny, and black. I've been running a bunch of tests trying to figure out why this happens, but I can't find one consistent pattern. I've tried both with and without the accelerant sold along with this product. I'm completely stumped. I've googled every combination of search terms I can think of and have come up with nothing.

    Can anyone give me any kind of idea of why I'm running into this problem with Loctite 410? I am desperate at this point. The owner of the speakers is pressuring me to get them finished, and the last thing I want to do is screw up the last step and ruin all my work. It's become the job I wish I had never agreed to do.

    Countless guys have told me, "We used to use black Bostik for this." I contacted Bostik, and Bostik black has been discontinued for years, so that's not an option.

    My late brother knew how to do JBLs very neatly, but died in 2014 without every showing me exactly how he did it. He used some kind of black solvent-based adhesive, but I don't know which one. It might be 3M black weatherstrip adhesive, but I'm not sure. He didn't want anyone around distracting him when he did it, so he literally took that secret to his grave.

  • #2
    I have used E6000 adhesive.
    It is available in black.
    I think I got it home depot.

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    • #3
      High humidity will make some CA products cure on the outside as a skin very quickly causing "blushing". Which is a whitening affect caused by light refraction because the amorphous material below the dried surface distorts it as it sets up. But this is just me blathering some crap I happen to know about from entirely other experience. I've never reconed a speaker. I would try to remain patient and use the product Jazz suggested.
      "Take two placebos, works twice as well." Enzo

      "Now get off my lawn with your silicooties and boom-chucka speakers and computers masquerading as amplifiers" Justin Thomas

      "If you're not interested in opinions and the experience of others, why even start a thread?
      You can't just expect consent." Helmholtz

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      • #4
        I live in the American Southeast, so high humidity is a fact of life.

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        • #5
          Don't CA products tend to being brittle anyway? I wouldn't think that's a good property for attaching things to a speaker cone. E6000 sure looks like a good product for the job.
          "Take two placebos, works twice as well." Enzo

          "Now get off my lawn with your silicooties and boom-chucka speakers and computers masquerading as amplifiers" Justin Thomas

          "If you're not interested in opinions and the experience of others, why even start a thread?
          You can't just expect consent." Helmholtz

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          • #6
            I ran some more tests, and I think I've finally figured out how to get a smooth bead.

            Using cardboard as test paper, you have to spray it with accelerant, let dry briefly, and then put down the bead of glue such that it skins over almost instantly. That gives you a smooth, shiny surface. If it does not skin over all at once, you get irregularities. Allowing it to cure with no accelerant gives you a chalky, irregular surface.

            Of course, that makes the application process very unforgiving. I got a one ounce bottle of Loctite 410, so I can't squeeze it continuously around the whole dust cap. I'll have to stop and let some air in. Even that brief pause is visible.

            Chuck, a number of reconers tell me that this is what they use. It does cut down time in the process, and it avoids having to deal with a lot of solvent fumes over a 48 hour cure. I guess if you have a big bottle of it and a steady hand, you can do a bunch of speakers very quickly.

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            • #7
              Maybe the accelerant is displacing moisture with solvent evaporation? Sounds like you're onto something. I might try a test heating with a blow drier on the same notion.?.
              "Take two placebos, works twice as well." Enzo

              "Now get off my lawn with your silicooties and boom-chucka speakers and computers masquerading as amplifiers" Justin Thomas

              "If you're not interested in opinions and the experience of others, why even start a thread?
              You can't just expect consent." Helmholtz

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              • #8
                Originally posted by Chuck H View Post
                Maybe the accelerant is displacing moisture with solvent evaporation? Sounds like you're onto something. I might try a test heating with a blow drier on the same notion.?.
                I don't think so. I think it's a matter of having it so the whole bead of glue skins over all at once. If you wait too long after applying the accelerant, the skinning slows down, and you start to get crystallized irregularities on the surface.

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                • #9
                  Don't listen to me, because I'm an idjit, but...

                  Originally posted by Rhodesplyr View Post
                  a number of reconers tell me that this is what they use. It does cut down time in the process, and it avoids having to deal with a lot of solvent fumes over a 48 hour cure. I guess if you have a big bottle of it and a steady hand, you can do a bunch of speakers very quickly.
                  ...it sounds to me that your performance criteria are completely different than those by the folks who do this repeatedly and rapidly. Take a breath and apply a more forgiving technique.
                  If it still won't get loud enough, it's probably broken. - Steve Conner
                  If the thing works, stop fixing it. - Enzo
                  We need more chaos in music, in art... I'm here to make it. - Justin Thomas
                  MANY things in human experience can be easily differentiated, yet *impossible* to express as a measurement. - Juan Fahey

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                  • #10
                    FWIW: (and not saying you can't) I don't use that glue for dust caps. I only use the CA glue and activator to glue the kit together (spider, coil, and cone). There is a different glue for dust caps. I just looked at the container to see what it is, but it has no specifics. It just says for dust caps and lead wires.
                    "I took a photo of my ohm meter... It didn't help." Enzo 8/20/22

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