How can you make a belt out of tubing?

[Dave001w]

We have some FreelinWade plastic tubing and would like to belt a belt with it to run it off of a motor.... how would we make a belt out of this that is the perfect size to run between 2 pullies? we are mainly interested in how we would melt the ends together to make a strong enough bond.

We have seen this done before at some competition during Rebound Rumble.

[cmrnpizzo14]

We did this, but with pneumatic tubing. All you have to do is cut it (being a slanted cut instead of square helps so that you can get a larger contact area) then use an electrical heat gun to melt it together into a loop. Works very well and we machined simple pulleys for it.

http://igknighters.com/Robotics/Resources.php

We have video and CAD up on our website of this.

[Cmac3082]

In 2012 our team used the round frc orange pollycord to make belts. We used a butane torch to get the two ends hit to the point where they melted but a soldering iron with a wood burning tip would work too. When both ends of the cord stared to melt we would slide them together and hold them tightly until they hardened. At the joint the cord would mushroom out making it hard to use but we used a disk sander to sand it down. We made a pulley on a wood lathe and coated it in some unknown epoxy so the cord would not slip. Hope this helps

[AdamHeard]

You really don't want to do this with pneumatic tubing, what you likely saw in 2012 was urethane round belt (polycord).

Mcmaster has it.

[cmrnpizzo14]

Originally Posted by AdamHeard

You really don't want to do this with pneumatic tubing, what you likely saw in 2012 was urethane round belt (polycord).

Mcmaster has it.

I was on the team making them. We had a surplus of pneumatic tubing and began using that to make belts. It worked well and you could get lots of it very cheaply in many different colors.

[AdamHeard]

Originally Posted by cmrnpizzo14

I was on the team making them. We had a surplus of pneumatic tubing and began using that to make belts. It worked well and you could get lots of it very cheaply in many different colors.

There is no way it worked well in comparison to polycord. It's not grippy and it's far stiffer.

You'd achiever far, far better performance with polycord.

[cmrnpizzo14]

Originally Posted by AdamHeard

There is no way it worked well in comparison to polycord. It's not grippy and it's far stiffer.

You'd achiever far, far better performance with polycord.

I have never used polycord so I can't speak for the direct comparison but 3173 has in fact used pneumatic tubing as belts and been happy with the performance. Originally we saw 2056's robot in 2011 @ FLR (which I believe used polycord) and someone from our team went and talked to them and came back with the (mistaken) conclusion that they were using pneumatic tubing on their claw. We switched our claw to use pneumatic tubing in Boston for our second regional and were very happy with the switch.

In 2012 we used it as belts on our intake and elevation system. Before we really figured out how to make them we suffered from some of them breaking. We perfected the technique by the time we went to St. Louis and had no complaints during CMP.

I'm sure in many instances polycord is better and grippier but for a team that did not have any at the time (and still does not because we have not found a reason to switch) pneumatic tubing was a very successful alternative for us.

[Breadbocks]

How effective are tubing/polycord belts for transmissions? I'm working on an RC car, and was redoing the gearbox and want to replace a pair of gears with a belt, but I was worried it'd slip off at the RPM it spins at.

[Tmaxxrox97]

We have used polycord to make belts in the past two years and they worked very well for us. What we did to join them together was to take a soldering iron with a large flat tip and melt the two ends of the cord. Once they were molten we slid them off the tip and together until they hardened together. We then sanded off the excess material around the joint.
Hope this helps a little.

[Chowmaster4695]

I think you may be referring to orange polycord. I don't think pneumatic tubing would be good for this. We made the bands by cutting two opposite angle cuts and then holding them together while using a blowtorch to melt the ends. Fast and quick. After the polycord starts changing colors,we then dunk it in a bath of ice and use a grinder to grind of the excess spilled out (we only have a hand one, but bench grinder would work great). We usually make the polycord 30% shorter so we can stretch it nice and tight on the robot.

[cglrcng]

We used the round polycord during Rebound Rumble (thicker & much smaller hole and very stretchy unlike the pnumatic tubing), and used a small alum. 1/2" barbed nipple w/ a center outside diameter equal to the outside diameter of the cord, so it worked perfectly w/out jambing up our pulleys as the joints rotated through), that barbed joining nipple was nearly impossible to push into each end, especially when it was stretched on the pulleys installing in the bot, but very hard to pull back out (usually had to cut those barbed nipples back out w/ a razor knife to re-use them), to join both very straight cut w/ a razor knife ends.