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This is a section of the ball chain from my roller blind. It seems to be a length of braided polymer cord with little thermoplastic spheres moulded around it. ball chain

It's one continuous loop and I cannot for the life of me find a join. I know connectors exist that clip around two of the balls, but this doesn't have one. I also know you can connect metal ball chains seamlessly by deforming one of the balls, but I can't see that working here.

A knot in the cord would be bigger than the balls. You could maybe bond the cord thermally and mould a new sphere to hide the join but I can't imagine the installer would go to that amount of trouble. Unless they just come that way out of the factory.

I need to make it shorter, and I know I could just get a connector but I have perfectionist issues regarding making things worse.

Spike
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4 Answers4

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Cut two of the balls in half, heat up the cut sides and fuse them together.

(probably you want a slight excess (over half) as there will be some ooze when you're smushing them together)

Alternatively join the line by fusing the ends together and then cover the join with epoxy formed into a ball - perhaps make a mould from silicone.

Jasen
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The pull cord is fused into a loop of that length at the factory. It's most likely done with heat, since plastic likes to melt, ooze, and form a single solid when heated. The pre-fuzed loop is installed at the factory over the gear in the head rail during the assembly process.

In order to install a shorter cord, you'd need to carefully disassemble the side of the head rail where the pull cord is (there may be springs and/or other little parts that will do their best to escape and run off to wherever it is that small parts go to die), then remove the too long cord and replace it with a Goldilocks-style "just right" pull cord, then reassemble.

You could, of course, attempt to cut and refuze the pull cord yourself. I'd suggest putting a small piece of tape on a ball when the blinds are all the way closed one way, then pull the cord to adjust the blinds to all the way closed the other way and see where that ball ends up. The goal is to find a ball that does not actually go through the gear mechanism if at all possible. Keep trying different balls until you find one that doesn't.

Once you've found this one, you know where to start your disassembly of the existing pull cord. Cut the cord or ball and attempt to reassemble. Both Solar Mike and Jasen have provided good suggestions on how to do that. By working at a point where the cord doesn't go through the mechanism, you'll minimize the risk of a "not quite right" fix jamming in the mechanism because it's too big.

If you find that doesn't work, or that it doesn't hold as hoped, you'll have to go with the replacement method.

FreeMan
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Other answers here are good, but the spectacularly lazy one is this:

Take up the slack in a loop (where it doesn’t want to run through pulleys in either direction) and zip tie the loop, top and bottom.

Have an adult beverage.

Aloysius Defenestrate
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You could open out the weave of the two ends, remove half the strands of the two ends and weave then the two ends together.

Once joined like that the joint is very strong - I have done it for tow ropes...

Only suggested removing half the strands to keep the overall diameter the same.

Solar Mike
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