Chief Delphi - Polycord Problem

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Polycord Problem

We are using 3/16 OD hollow yellow polycord for our ball lifter (McMaster 6567K56). After testing it and it working barely with almost no tension, we decided to cut off about 5% to tension it. This looked proper, but a few of our connections were failing randomly when they were not being run.

We think we may have over-tensioned it and will probably need to add some polycord to lengthen it, but before we do that and add possible failure points, are there any tricks to use to keep the connections from failing?

I have seen some posts about polycord welding, but im not sure if that works with hollow polycord...

Thanks!

Re: Polycord Problem

We are using the clear version of what you have, and we have welded it with great success. One of our lead mentors helped us by creating a soldering iron with a flat brass head. This tool allows us to melt the poly-cord ends, and then slide the tool out from in between.

Re: Polycord Problem

Quote:

Originally Posted by BeltSanderRocks (Post 1128594)

I used those yellow hollow ones before. It is very difficult to get them in and keep them on. At that time, I thought welding the cord is difficult and the 3/16 yellow ones are less expensive comparing to the 1/4 orange solid ones. Welding turns out to be very easy. The key is not to have the temperature set too high. Use a flat blade so it is uniformly melted. To allign it, we use a short C-channel aluminum section. We just push both ends in, hold them in place for about 30 seconds and then it is done. To be safe we usually wait overnight and do not stretch them. I have never had one come apart.

Re: Polycord Problem

We are using the yellow 3/16 polycord from McCarr. We started with %10 stretch and back off a bit because we did not need that much tension.

Only a problem with one cord on a connector. The cutting edge of the barb is easily damaged. Do not hold it with a tool. We drilled a hole in a plastic block to hold the barb to get the cord started on one side of the barb. Then used pliers on the poly cord to push the other end on. Make sure the cord is cut square & the cords meet in the middle of the barb. Little details matter on this.