pic: Polycord Welding

[codes02]

Any reason you guys are melting the polycord together instead of just tieing it?

My team has decided to go with tieing due to concerns about the melted together joint being weak and our inability to identify any benefit to melting it

[BrendanB]

Originally Posted by codes02

Any reason you guys are melting the polycord together instead of just tieing it?

My team has decided to go with tieing due to concerns about the melted together joint being weak and our inability to identify any benefit to melting it

Unless you are doing something wrong then your joints should not break. I'd be more concerned with my knot untying or messing up the movement of the ball/rollers.

The way we have done polycord welding was with a heat gun (or flame but you have to keep the cords in a magic spot so they don't burn and so that they aren't too far away, heat gun preferred). Once you see the two cords turn liquidy on the end we pushed them together and held them for a minute or two until they cooled. Once they have set for a while we would take a knife and shave off the loose ends. We did this in 2009 and I can't remember a single joint breaking it is wicked simple and so easy I don't know why you would consider tying them.

Take a small segment and trying melting them together as a test before resorting to tying. A little too sketchy with polycord for me and I have never seen that done before.

[Dad1279]

Originally Posted by codes02

Any reason you guys are melting the polycord together instead of just tieing it?

My team has decided to go with tieing due to concerns about the melted together joint being weak and our inability to identify any benefit to melting it

Teams are melting it because that is the proper method for joining/welding it.

Welded joint is as strong as the cord itself. We pull test every joint, and have never had a failure in competition.

If your team does not want to join it with heat, I suggest using the hollow polycord with connectors or find another belt system to use.

[V_Chip]

For out polycord welding we milled out a simple assembly like above.

Two 1" blocks of aluminum are attached to a rail system on a base. The tops are notched to cradle the polycord.

On one of the sliders there is a hole just large enough to put the polycord through. Each end of the cord is slid through and cut against the face of aluminum with a razor blade so that it's perfectly flat.

The hot knife is then held between the seated ends. Once hot the rail cradles are slid together and form a clean and even "weld"!

I can upload some photos upon request.