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Securing cable ties to launch tube

Discussion about Compressors, hose, pipes, fittings, launchers, release mechanisms, and launch tubes.
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SaskAlex
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Securing cable ties to launch tube

Post by SaskAlex » Tue Feb 09, 2010 12:37 pm

Well, I'm working on a cluster launcher that will use the Clark Cable tie method. I played around a bit with different ways of securing the cable ties to the launch tube. Most methods I've see have either used pipe clamps or lots of glue. The pipe clamp is clean and simple, but a little bulky and limits the length of your retention sleeve. And glue can be a pain if you have to adjust it for cable stretch or whatever.

Anyways, I just slid a short length of bicycle inner tube onto the launch for extra grip, and then secured the ties with some fine wire. Just make a bunch of lengths of wire long enough to go around once, and twist each one tight with a pair of pliers. It holds it nice and snug. You might not even need the inner tube. Just thought I'd share, because I haven't seen it done like this before.

Here's an example. It's just a test setup, I'll definitely be using more ties on the actual launcher!
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Spaceman Spiff
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Re: Securing cable ties to launch tube

Post by Spaceman Spiff » Tue Feb 09, 2010 1:37 pm

I like the inner tube idea as well as the wire idea. I wonder if you could get the same results by just winding a whole lot of wire around the ties instead of using multiple short lengths. What if you used fishing line or something and wound it up and down. Or how about this: wrap it with a long length of cotton thread until you had a layer of thread a few millimeters thick and glue the ends down with epoxy. Take the whole thing and dip it in boiling water for a minute and pull it out and dry it with a heat lamp or put it in a warm oven. The thread would shrink and pull really tight. You could paint the whole thing with a layer of glue or varnish and it would harden into a solid tight clamp. It would be smooth (depending on how neatly you wound up the thread) and would be very clean.


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SaskAlex
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Re: Securing cable ties to launch tube

Post by SaskAlex » Tue Feb 09, 2010 6:38 pm

Yep, I find the inner tube handy for a lot of things. But if you need grip, make sure you turn it inside out first and take some steel wool or fine sand paper to it. The inside has a low friction powder/coating.

Well your string idea seems like a lot of work, but could look very good. I plan to have my wires hidden from view, though. If you do give it a try, you might want to look into serving. Try "serving a bow string" on youtube. It's a really cool technique for securing the ends of string that is wrapped around something many times. It would eliminate the need for the epoxy.

As for a single piece of wire wound many times, I tried that and it didn't work nearly as well. When you go to tighten it up by twisting the two ends together, friction prevents you from putting each wrap under tension. You really only get much tension on the last wrap or so. By twisting the ends of each loop, you are able to get way more tension than if you wound a long length around by hand.



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Spaceman Spiff
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Re: Securing cable ties to launch tube

Post by Spaceman Spiff » Wed Feb 10, 2010 4:53 pm

I'll look into "serving" and see if my idea for shrinking the string can create tension. Thanks for the clarification!


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U.S. Water Rockets1
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Re: Securing cable ties to launch tube

Post by U.S. Water Rockets1 » Sat Feb 13, 2010 11:15 pm

Spaceman Spiff wrote:I like the inner tube idea as well as the wire idea. I wonder if you could get the same results by just winding a whole lot of wire around the ties instead of using multiple short lengths. What if you used fishing line or something and wound it up and down. Or how about this: wrap it with a long length of cotton thread until you had a layer of thread a few millimeters thick and glue the ends down with epoxy. Take the whole thing and dip it in boiling water for a minute and pull it out and dry it with a heat lamp or put it in a warm oven. The thread would shrink and pull really tight. You could paint the whole thing with a layer of glue or varnish and it would harden into a solid tight clamp. It would be smooth (depending on how neatly you wound up the thread) and would be very clean.
That's a very interesting suggestion, spaceman. A twist on your idea would be to wrap the ties with a fine wire. Magnet wire from a motor would be a good type to use. The twist comes when you apply a current to the wire to warm it up to about 150-200 degrees (use gloves) before you wrap it. If you wrap in a few layers and then tie the ends together before removing the current source. The wire would cool and contract a significant amount and clamp down like a vise.


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