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Old 03-29-2011, 01:25 AM
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jharding58 jharding58 is offline
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When you use the triple wrap it is also important which way you install the shock cord mount in the tube. The open or wider end of the wrap should be toward the NC with the larger surface (usually the first fold) toward the center. This reduces the shear force on the paper to paper joint when the NC pulls out the chute.

With a Kevlar cord I usually trap a knotted loop between the top of the motor clip and the motor tube and then either slide a centering ring just up to the cord if the design permits, or use a motor clip retainer band and CA that against the end of the clip. As mentioned the knot for the cord and elastic shoudl be about 1/2" inside the tube to prevent zippering.

With elastic shock cords I would double knot the end of the elastic and then use some AB Fixit putty to retain the elastic. If you scuff the inner surface of the tube where you plan to affix the putty (the requisite NC shoulder plus 1/2 inch) it will bond much more easily. You can smooth over the putty to create a small lump on the inner wall with the knotted end of the elastic trapped below the lump. An alternate solution is to putty a loop of kevlar into the upper part of the tube and then use a knot to attach the elastic. That way when the cord eventually becomes brittle you can tie one on...
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Last edited by jharding58 : 03-29-2011 at 02:18 AM.
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Old 03-29-2011, 06:35 AM
jspitza jspitza is offline
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So sorry for not responding to all of the recent posts-laptop crash and burn:
Thank you very much for the picture jharding58! I ended up tying the kevlar around and through the second centering ring and then using a few drops of wood glue to secure the knot. This and the other ideas and designs will just need to be filed in my "how do I do this?" section, which at this point is getting rather large. Take care, Jeff
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