Force of latex tubing

[sbell25]

sbell25, Killer 7's method is designed for stretching LRT over a barb. If we want to slide an entire tube underneath, things become more complicated. But the underlying concept is the same.

I thought that stretching LRT over a barb (namely 1/8" LRT over a 1/2" barb) was the goal here. Killer 7 did get 1/2" tubing onto a 3/4" hose barb with his 'ice cone' method. Although I admit that 1/8" tubing onto a 1/2" barb would be a lot more difficult, if not impossible, but it's the best method we have so far.

While writing this, I just had a thought about another method for stretching LRT over a hose barb. Anyone ever heard of Castration Ring Applicators? They're a form of pliers used to stretch castration rings. For those who don't know, castration rings are very thick rubber o-rings used for castration or tail docking on farms.

If you look at the picture, you'll see the 4 little hooks at the end. The o-ring goes on there, and then when you squeeze the handle they all move away from each other, stretching the o-ring. I remember we had one back in NZ a long time ago, and I'm pretty sure it'd stretch far enough for our purposes. However, I'm not sure whether it'd be powerful enough for LRT, although those o-rings are pretty thick.

I might have to do more research on this.

[Silence]

Nope, the goal is to layer rubber tubing over rubber tubing. The main problem that comes up is that you have to stretch the outer tube at all points along its length to prevent friction. An alternative would be to fold in the inner tube if it's thin enough.

Those...uh, applicators...use the right concept. The trick is implementing one to stretch a really long tube without taking up the space in the middle.

Perhaps a pressure-based system would work. If you could clamp the outer tube in each side of a piece of pipe, then create a suction inside the pipe, the bladder would expand enough to slide a smaller tube through. A conventional clamp wouldn't work though, because you can't directly access the barb from the outside.

[sbell25]

At McMaster, the 1/8"ID-3/4"OD-.3125"W tube has a maximum pressure of 85PSI.
If we could somehow get that onto a 1/4" or 1/2" hose-barb, you would have quite a powerful CPH right there.

If you find a way to stretch it, that might be a revolution, but in my experience, getting substantially larger diameter barbs into a smaller tube is impossible.

I was mainly talking about the difficulty of sticking a significantly larger barb onto a tube.

I'm pretty sure (for the later part of this discussion at least) we're talking about stretching LRT on a larger barb here. That's why I mentioned those applicators as a solution to the problem.

Besides, for actually layering LRT, Killer 7's method already seems to work quite well.

[Silence]

You're right...thanks. I thought WaterWolf wanted to layer LRT to get 85 PSI, not stretch small 85 PSI tubing over a larger barb. Thanks.

In that case, the ice cone method should work well.

[Ben]

I started looking at the relationship between wall, diameter, and pressure in LRT a few days ago.

First problem is that most tubes only have a precision of 5 PSI. This is making my attempts to model a function harder because I have to compensate each data point manually and that introduces errors.

The second problem is that sometimes pressure drops as wall thickness increases when keeping diameter constant. I don't know if those are typos or if pressure does really decrease.

While writing this, I just had a thought about another method for stretching LRT over a hose barb. Anyone ever heard of Castration Ring Applicators? They're a form of pliers used to stretch castration rings. For those who don't know, castration rings are very thick rubber o-rings used for castration or tail docking on farms.

Those look close to what we need. They might not be strong enough, so some further research or testing is necessary. Good idea.