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Roller machine to create pressure on and pull through ribbons of bark/fiber, similar to a pasta maker--ideas NEEDED. Answered

I'm working on a project in Nepal to remove the bark from the fiber growing in the stalk of a wild plant (bast fiber).

The "bark ribbons" are stripped off the plant, with the fiber adhering to the inner side of the bark. The plant grows back so it's all very environmentally sustainable.

We soak the long (1-2meters) bark ribbons for 24-48 hours and then, if beaten, can break the "glue" (pectin) that's holding the bark and fiber together. We've run them through an industrial  roller system and it worked very well, without damaging the fiber the way beating does. A local machine shop wants to build an expensive, heavy duty, roller system and we'll go for this eventually. However, in the meantime, we'd like to build a smaller, simpler machine, maybe a table top one rather than free-standing. We can hand crank it, or use a bicycle mechanism.

We need to be able to adjust the pressure--the distance between the two rollers--to make sure we are breaking the pectin bond between the two materials, fiber and bark.

We have access to steel pipe, PVC, cast iron makers, gears, etc. If anyone can help me with plans I'd really appreciate it, as would many impoverished Nepalis.

I've included photos of the industrial machine (the first 6) we tried and will eventually make, as well as a pasta maker and one other machine. The industrial machine had three rollers but they removed the outlying one, not above/below another, as it didn't work as intended.

Thanks so much in advance to all you wonderfully creative Instructable-ers.
Shanti Mama


The trouble appears to me to be the forces needed to do the actual breaking down.

Have you any idea what forces are used Shanti ?

If you make a small machine, it will only accept very thin ribbons of plant. Think of it as making a narrow machine, and you will be OK.


I'm not sure what you mean by "the forces." Pectin holds the bark and fiber together. We loosen it up with the 24-48 hour soaking. Then we can push the two components apart. Do you mean a small machine in terms of width of rollers? The bark ribbons are only about 2cm wide so it's not a problem. Thanks for thinking about this.

I dont' see what the action of the rollers is. Does one rotate in opposite direction to the other to shear the fibres out or what ? Does it take a lot of pressure on the bark to release the fibres after the soak ? Yes, I'm thinking of a narrow machine, being easier and cheaper to make.

Yes, it's the pressure that "pushes" them apart after the soaking has begun to decomposition of the pectin holding them together. The rollers don't move in opposite directions. If one roller is moving at a very slightly slower speed that would be good. But in the one we tested, the rollers moved at the same speed. In that machine, one of the rollers has grooves on it (the upper roller in the first picture), but I'm not sure this is necessary. I want to try it with flat rollers first. Imagine a PB&J sandwich and you're trying to separate the two pieces of bread so need to get the PB&J sliding apart. Not a great analogy, as the bread would just squish! Thanks for thinking about this. Shanti Mama

No. I had one but someone took it apart to clean it and wasn't able to put it back together again... But that's the idea. The industrial strength machine we tested is just like a giant pasta maker.

I wonder if you can use the light forces in a pasta maker to do this on a very small scale that's all.

Maybe you should post a question, and some pictures....How do I put this Pasta machine back together ;-)

I can't see how we can avoid you having to make a machine for this, but I would argue it doesn't need to be anything like as heavy as the one you are being persuaded to have made, since it can be very narrow.


It sounds as if you have the items you would need to make what your wanting. Use a section of pipe with a bearing so it spins as a base roller. Then add a pipe roller above or below it connected to gears for hand cranking. The adjustment could be as simple as a slot that the base roller sits in as it spins or add a weight to give more compression. The addition of possibly a third roller could also be adjustable to aid in compression. Just some random thoughts that came to me while reading your question.

Thanks, Redneck. Would you mind expanding on this a bit? I'm not very experienced with mechanical stuff. For example, "with a bearing" means? Thanks

Will try to comprehend this. I'm a pretty quick study, but am in way over my head these day with textiles, biochemistry, mechanical engineering, etc. Thanks for pointing out this resource. I'm thankful for any others, as well. Shanti Mama

We can't get a clothes wringer here, unfortunately. I'd thought of it, but... Not even a bucket with a mop wringer. Thanks, though.