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  • Copper tape adhesive losing conductivity.

    I don't know if others have run across this, so I thought I would ask. On my new track, I used copper tape with conductive adhesive. I tested it out before taping my track just make sure. So, after driving on my new track for about 3 hours total over a couple days, two spots on the track went dead. At first, the failures were intermittent, but became hard failures after about 15 minutes. When I tested the track with a voltmeter I found the dead spots were where there was a break in the tape that had been taped over. I cut out the area that was dead and put down new tape and the problem went away. Has anyone else experienced this?

  • #2
    I bet the dead areas were in curves, right? They are caused by pulling too much tension on the tape when you laid it. As it settles in, the stressed spots just pull apart. Be sure to burnish the crap out of your patches or they will come up from traffic over them.

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    • #3
      My oval is 16 years old and about 2 years ago there was a dead section in one corner. I take total responsibility for the problem due to unknowingly stretching the tape during original application which caused some wrinkles over time. At first I just put short new pieces of copper tape over the breaks, but that was a poor fix. To do it right I pulled up the dead section (about 12" long) and re-taped it with a piece of tape about 1" longer on each end. Put the new tape under the existing tape at the beginning of the problem area (based on direction of travel) and with a drop of solder on the tip of your iron put it between the layers and quickly press or roll them perfectly flat. Do the same on the other end of the patch with the new tape on top of the old tape.

      My joints are virtually invisible and the problem is completely solved. Harry has a short video of this procedure he may post if he sees this. That's how I learned about it.

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      • #4
        Yup, you just had a tape break. It happens. The good thing about conductive adhesive that it makes repairs easy. Don't sweat it, just tape over and be done.
        Come Race at The Trace!
        Timberline Trace International Raceway - SW of Mpls, MN
        https://cults3d.com/en/users/chappyman662/creations

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        • #5
          'conductive adhesive' makes me laugh, no adhesive in the world is as conductive as metal, it may be conductive of sorts but only minor.
          Kevan - Isle of Man
          Life is like a box of Slot cars...🚓🚗🚚🚜

          Comment


          • bdsharp
            bdsharp commented
            Editing a comment
            I agree. I once scraped off the "conductive" adhesive from some 3M copper tape, rolled it into a booger about the size of a BB and measured with an ohmmeter. Very high resistance. When making track repairs, even the tiniest point of copper-to-copper contact will test as a good repair.

          • HO RacePro
            HO RacePro commented
            Editing a comment
            What makes the adhesive conductive is not the glue, it is the small copper particles embedded in the glue. Those particles bridge the gap between the copper foils allowing current to pass. 3M knows their business. It does work, although the conductivity might be substantially reduced.

            When I have made repairs to copper tape I have peeled back several inches on either side of the break, drilled holes through to the underside of the track, passed the peeled-up ends through the holes and stapled them to the plywood underneath. Then I laid new tape over the gap, passing the ends through those same holes and making contact underneath the track. You can staple the foils face-to-face or make a solder connection. Both make good joints, but stapling is definitely easier.

        • #6
          After you tape over the breaks in the tape, use a pin to puncture the patch in many, many places on both sides of the break then burnish over it to smooth out. The idea is to break tiny holes in the patch and push the metal of the patch into the tape below.
          Team SCANC
          Woodland Trace Raceway - SlotZuka - Bent Tree Raceway
          OFI - Buena Vista Motorsports Park - Slotkins Glen
          Leadfinger Raceway

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          • #7
            The dead spot WAS where a break had been taped over with an overlap of about 1/2". I removed the taped over section, plus about another 1" and taped over the whole area, overlapping about 2" on each end.

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            • #8
              Fast is right. I completely forgot about pin pricking. a Circuit Writer pen is nice for the ends of the patch, too. But definitely do the pin pricking.

              Comment


              • waaytoomuchintothis
                waaytoomuchintothis commented
                Editing a comment
                Just any kind of household pin.

                I'm vibrating from resisting saying something like, "small pointy thing women use for hiding in the upholstery of furniture to injure you when you lie down on the couch for a Saturday afternoon nap" There. I said it. I feel better now.

              • slothead
                slothead commented
                Editing a comment
                No better fix than to put some solder between the layers of tape - quick and easy and sure conductivity.

              • waaytoomuchintothis
                waaytoomuchintothis commented
                Editing a comment
                Trouble with that is that the adhesive melts the instant you touch it with the soldering tip.

            • #9
              Bal, Cut a small piece of copper tape. Remove the adhesive on the back with goo-gone or something like it. Then solder the piece directly on top of the area needing to be repaired.
              First lay some solder on the piece to be repaired, then place the new copper piece on top and heat it so it melts the copper underneath.
              I think Harry did a vid of this some time back. Easy to do.
              Glen
              "Nothing is foolproof to a sufficiently talented fool."

              Glen
              Zen Raceway
              Severna Park, MD

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              • #10
                On my first track, I put the second piece of tape over the lower piece and drove a copper tack through both pieces. That seemed to work pretty well. Punching a hole into both layers of tape with a nail, then filling the nail hole with solder works, too. The problem with either tack or nail is you can break the side of the slot. I was hoping the conductive adhesive copper tape would make things easier. So far, my retape job worked. I guess I will wait and see.

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                • #11
                  When ever I make a patch or any kind of overlap I use the point of my utility knife and pierce the overlap area repeatedly. It allows better connectivity between the two layers.

                  I also race heavy brass 1/24 car on a couple of other tracks, but test them on mine. They can be hard on the copper tape.

                  Comment


                  • Fast Co.
                    Fast Co. commented
                    Editing a comment
                    Yes. 1/24 cars can be hard on copper tape. If I was doing a 1/24 track I would definitely do braid instead of tape. But for 1/32 I actually prefer tape.

                    Two keys to laying down copper tape:

                    1) do not stretch it as changes in temperature will naturally cause it contract and expand at a different rate than mdf. And the contracting can cause the tape to split.

                    2) realize that there will be some wrinkles in the tape especially in the turns. Simply burnish the wrinkles down as close to flat as you can get them. The cars will not notice and the burnishing will give you a better bond with the track surface.
                    Last edited by Fast Co.; August 2, 2021, 11:13 AM.

                  • Bal r 14
                    Bal r 14 commented
                    Editing a comment
                    Boy, that takes me back! I raced 1/24 on a copper tape track at a small hobby shop in the old days. I think the shop owner had to retape the track about every 3 months. That was before the big commercial tracks. I lost interest when the huge commercial tracks with 6 - 8 lanes, vacuum formed bodies and sponge tires became popular. There was just no way my realistic scale AMT plastic bodied cars could compete.

                  • waaytoomuchintothis
                    waaytoomuchintothis commented
                    Editing a comment
                    That's because you had a slot car. That other crap is what wrecked the hobby for many years.

                • #12
                  What makes the adhesive conductive is not the glue, it is the small copper particles embedded in the glue. Those particles bridge the gap between the copper foils allowing current to pass. 3M knows their business. It does work, although the conductivity might be substantially reduced.

                  When I have made repairs to copper tape I have peeled back several inches on either side of the break, drilled holes through to the underside of the track, passed the peeled-up ends through the holes and stapled them to the plywood underneath. Then I laid new tape over the gap, passing the ends through those same holes and making contact underneath the track. You can staple the foils face-to-face or make a solder connection. Both make good joints, but stapling is definitely easier.
                  Ed Bianchi
                  York Pennsylvania USA

                  Comment


                  • #13
                    I get the impression most feel my conductive adhesive tape won't last. I will just have to deal with it. I suspect I'll probably tear this track down and start a new one before it becomes a serious problem.

                    Comment


                    • #14
                      If you stay away from the heavy brass cars it will be fine. In a finished basement there is very little maintenance. In a garage with extreme temperature changes you may need to massage the tape from time to time.

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                      • #15
                        Good googly moogly, you don't have to go through all this major work to repair a break.

                        -Harry

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                        • Bal r 14
                          Bal r 14 commented
                          Editing a comment
                          That's a neat trick. Thanks!

                        • gsnopoint
                          gsnopoint commented
                          Editing a comment
                          This is the vid I was referencing. Works great. Thanks Harry
                          Question Harry, did you need to remove the adhesive in the tape used to do the repair?
                          Last edited by gsnopoint; August 2, 2021, 08:22 PM.

                        • Fast Co.
                          Fast Co. commented
                          Editing a comment
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