pic: (447) Is this legal?



This is 3/8 od, 1/4 inside flex hose. Is this a legal pneumatic? I seem to remember Carmel using something like this on their removable arm last year.

Don’t think so:

Q&A #1407
**Q:**Question ID 1179 did not answer the question. After much discussions there has not been a concensus as to whether 1/4" coiled hose can be used for expansion reasons? We would like to see a yes or no answer please.
**A:**No. It does not pass the 2005 Part Use Flowchart for a fitting or a valve.

But this is allowed:
Q&A ID#1616
**Q:**Can we coil the provided hose for the pneumatic system our selves?
**A:**Yes.

And that is what we did…

I made sure of the first answer so no that hose is not legal. Yes we made our own. It’s not quite as good as bought but that’s how it goes.

I also noticed that it is not the SMC blue hose so again not legal. By what I hear it has to be the blue hose as that is what was supplied in the kit.

Our hose was a Opaque black color. I just did our pneumatics today.

How do you coil it yourself? Do you heat it or something? Because I wouldnt think the judges would like to hear that you had heated the hose…

We coiled our hose by wrapping it around a piece of PVC pipe, taping it down on the ends, then hitting it with a heat gun set on low. It didn’t take very long at all, and coiled beautifully after that.

-Rc

There is no rule against heating the tubing, just modifying. It is still tube and it still has the same properties. If you heat it too much it will shrink and give less air flow, so be carefull.

Lets go through the 2005 Part Use Flowchart.

Is the part a pneumatic component? YES

Is it an Air Cylinder ordered from the Custom Cylinder Order Form? NO

Is it a purchased fitting or valve rated for 125psi
Or
A purchased cylinder or rotary actuator identical to those available on the Custom Cylinder Order Form? NO

Previous year’s pneumatic components
BUT ONLY
the cylinders and solenoid valves? NO it may not be used

I hope this helps in how to use the flowchart.

I’d be REALLY careful about this. “It still has the same properties” could be argued against strongly from a safety standpoint, for 2 reasons I can think of:

  1. If it remained coiled after you heated it, it permanently yielded. How do you know the plastically deformed material has the same properties (tensile/rupture strength, yield strength, elongation) that it had when it was qualified/certified to its pressure rating? If it hardened locally after heating the material may not redistribute stresses the same way.

  2. How do you know that the thickness remained the same after heating? If it shrinks and gives less air flow, it could just as easily expand under load and cause both thinning and a larger diameter. Diameter and thickness are the primary variables in hoop strength - how do you know it’s still qualified/certified to its pressure rating?

I think you’re pushing this one a little too much Steve. My $.02

We coiled our own air hose for use on our telescoping arm last year, and it passed inspection at a regional and then again at the championship. We used 1/8" airline though. We coiled it by wrapping it around a piece of wooden dowel and taking a heat gun to it very carefully and slowly.

Awsome, thank you guys very much!

Guess I will have to take the 10awg wires I ran around it off :frowning:

I have ours coiled with wiring also as I am feeding 2 Festos with one tube so I need wires to activate.

Gary, point taken. I am a stickler for safety so I have checked the tube with 125 lbs pressure after winding. There is also the safety that I have been harping about were coiled tube would be safer than straight. When designing the game they know that there will be issues with tube having to go distance safely. To be able to purchase the proper tube would be the proper thing for FIRST to allow. They allow so many other things when it comes to motors and gearboxes etc why not Pneumatics?

I understand their great concern over pneumatics: injuries from high pressure fluid systems are very common. It is just too easy to have a pressure vessel or hose or whatever burst and turn into a projectile. But, I think with the 60 psi restriction, they can be a bit more lax on the other pneumatics rules. Besides the fact that damaged pneumatics stuff will be a lot less dangerous at this pressure, I don’t think you can even find any pneumatics components rated for less than that pressure. You’d have to try to screw this one up.