WE are attempting to cut and attach poly cords together to be used on some intake rollers. Any advice on how to. I search the internet and you tube with not a lot of luck.
I am hoping to heat it with a lighter. Any advice or suggestions are welcome
Thanks
https://www.chiefdelphi.com/forums/search.php?searchid=7795543
Those are the search results from simply searching “polycord.”
We use a soldering iron with a flat blade and heat press both sides to it till they are nice and melty, then pull the blade out while still pressing the ends together then wait for the cord to cool before applying tension. We have a homemade jig that keeps the cord inline so no offsets in the weld happen.
Thanks and I will give that a try. I did the same search for “polcord” the link don’t really have how to. Does it help to cool it with water at all?
IMO, don’t even bother with melt-connecting polycord, go with hollow-core round belting and use connectors to link ends together. It’s 1000x easier than fighting with a soldering iron and trying to get the tension just right, and it works exactly the same. The only tools required are a pair of scissors.
Hollow-core belting with connectors isn’t permanent, whereas welding solid-core belting is. 423 used hollow-cord belting for our intake last year and we would pop cords a number of times each competition. At one point a ref (or someone official I don’t remember) told us we need to fix the problem or we would start getting fouls. We replaced all the belts and that corrected the problem temporarily, but it came back after a number of matches. This isn’t to say that hollow-core belting doesn’t work (it does), just that IMO the time you save from tracking down popped belts from field staff and re-connecting them outweighs the slight increase in complexity of assembly. YMMV
We used a lighter and just held the ends above it until they were melted. It worked decently enough, but is slightly dangerous in terms of drips.
Our team creates a jig to put together the two ends. We then cut the cord diagonally in order to create a larger connection surface. Heating is provided by a harbor freight heat gun. We’ve done this successfully in 3 out of the last 5 robots. The Bronc Botz have used polycord since 2012.
We bit the bullet a number of years ago and bought a Fenner Belt welding kit.
It is pricey but it has served us well for 10 years…
The mini clamp is pretty nice and even if you just bought that… and adapted a soldering iron to use it… it might be worth looking at
We have never had a failure of a belt due to the joint. It is also pretty quick to use.
kit
http://www.fennerdrives.com/welding-kits-and-components/_/Welding-Kit-115v-w/-Mini-Clamp/
clamp:
http://www.fennerdrives.com/welding-kits-and-components/_/Mini-Butt-Welding-Clamp/
Their heating tool
http://www.fennerdrives.com/welding-kits-and-components/_/Fenner-Heating-Tool-115v-60w/
i am not saying there are not plenty of alternatives to this but for less experienced teams, its good to see that a solution exists from the belt maker. You might look at the mini-clamp and design your own.
If we are ever in an event with you we will have it in our pit.
thanks
good luck on the field
I am making a tutorial video about this and other stuff tonight.
My team is also using poly cord for our intake. What we’ve discovered works best for us is using a heat gun to melt each end, pushing them together, and then rolling it between two pieces of wood to make it flat. It also works best to have flat edges.
Last year, we used a piece of aluminum angle as a sort of jig and used my SMD rework station with a narrow nozzle to melt the polycord.
We made a jig out of a chunk of 2" diameter aluminum. Drilled a .25" hole through it then cut it in half on the band saw straight down the hole. Heat the cord, stick together in the jig and clamp it. The aluminum does a good job of pulling the heat out of the belt and it cures in under 5 minutes.
Since we made two of those we haven’t had a failed belt. Prior to that we had one fail every four or five times. With the two pucks we made, we can weld one and while that cures set the next one up.