PET ropes and filaments making (V4)
Hi guys !
Yann here, I already posted on “Finding a solution for PET” topic, but as the rope making takes a lot of experiement by itself, we decided to create a separate topic. So this part is a copy/paste from last one, and I will a some new imformation shortly !
First there is some parameters that are mandatory during the process :
– Keep equal tension in all fibers / yarns
– Equal rotation speed for all yarns
– Perfectly free rotation at the end of the rope
– Keep rotating all yarns while the strand start to appear but at lower speed
– Maintain reasonable pressure on the separator
Here are some parameters that have influences on the rope quality and that we had tested / will test :
– Bottle strip width and regularity
– Untouched strip or “pre-rotated” strip stabilised in this form with an air heater
– Flat bottle or grooved bottle (influence on regularity)
– Same bottle type or mixed bottle supply (influence on regularity)
– Fiber joining (knots, torsion…)
– Tension (at the end of the rope, by the rotation tour number…)
– Rope type : quantity of fibers per yarn, quantity of yarns per strand, quantity of strand per rope (currently making a 2 filaments per yard / 3 yarns per strand / single strand rope, a filament is corresponding to one bottle strip).
Some conclusion have already been found :
– Pre-rotating and heating the strip makes it look smoother and gives it a better reaction to torsion : the strip resistance being more homogeneous.
– The smaller the strip are, the better the rope appearance and smoothness is.
– There is no need to pre-rotate small strip (up to 3mm), but it is mandatory for bigger one to maintain a good appearance and a proper torsion reaction during the making.
– It is also mandatory to pre-rotate irregular strips for the same torsion reaction (risk of breaking in weaker spot before obtaining the right torsion).
=> Therefore the best material for rope making would be strips as small as possible, supplied from the same ungrooved bottle type.
And eventually we will continue working on the following point :
– finding the best cutting method to obtain small and regulare strip + automatised process
– if possible this cutting method works also on disparate and grooved bottles– finding a better connection method than knots
– when the process is mastered, experimenting on various filaments/yarns/strands quantity
A little bit more information on how the ropes are done.
First GIF :
Frist of all you must obtain some strip out of a PET bottle. As said on the post above, the thiner the strip is the better outcome you will get. Also using ungrooved bottle simplify the process. Out current cutting maching is a cutter blade placed on top of a calibrated cut on a metal beam. The depth cut shall be the strip width you want to obtain, and the cut shall be as thin as possible for the strip not to tilt during cutting. The bottle is maintained to the right angle with a metal guide.
We added a system that allow us to spool the strip autimatically in order to save time.
Further improvment have to be done on this machine :
– Better rigidity
– Easier and faster spool set up
– Better guiding system (this one is difficult to set up)
– Add a system to transform the flat strip into round filament
– Add a system for bottle preparation before strip cutting
Second and third GIF :
Then you can process a rope. Still with a drilling machine and a belt, three pins are rotating together. Then on the other side, the tention is maintained with a weight, but with free rotation possibility. You have to maintain your yarns separated until you get a satifying torsion in all yarns. Then the yarns are automatically turning arround themself making the rope.
You can vary the rope size by adding more filament, by using pre-made small rope to obtain a bigger one etc… Rope lenght is theorically unlimited as both system side are independent from each other.
Further improvement will also be done on this machine :
– Independant set up (instead of using a table)
– More versatility (more possibility in number of yarn & strand)
– Possibility to count rotation number (important rope caracterisation number : higher rotation number means denser rope, and denser rope means more tensilte resistant rope, but up to a certain limit, to dertermine for PET)
yeahh gifs! 👊
As I have some questions from time to time about what we would use the rope for. Basically everything you would use a normal rope !
Here some application already under testing : hanging clothes, lacet, bike luggage rack attachment, dog leash.
Also, we can use the strip directly to make various construction. Here an example on attaching a paddle on a wood handle. You can use the retraction propertie of PET to normally knot anything with a strip then heat it to really tight the attachment.
More example wil follow depending on our moment inspiration or needs. Some ideas that come to me immediatly :
– Stool woven seat
– Boat mooring…
Do not hesitate to give us ideas !!
I’ve seen some cool things folks have done like:
https://goo.gl/images/gY99CR that’s a thin copper strip threaded through wood like a shoelace.
Of course you could do something like knife or tool handle wraps: https://www.wikihow.com/Wrap-Paracord-Around-a-Knife-Handle
Or maybe seat weaving like:
Here’s someone who started doing a pretty decent looking hammock but gave up when he saw how long it took to make the rope.
I think a big thing is to just have some available to you all the time. Start thinking of how you could use it. Distinct colors will let you make things more interesting. How can you play with strength and texture? What’s it feel like in your hand? Would you want a few weaved together before you’d use it for a big lift? If a big dog gave you a big dog tug on it how would your hand fare. If it’s rough it’s not necessarily a bad thing. Maybe some sort of hand wrap or scrubby type thing like a louffa could be worked out.
One thing seems to come up is that each of these sorts of products is greatly enhanced by a familiarity with a relatively established set of skills. Like this rope product could probably benefit from the maker knowing about knitting, knot tying, weaving, or just a little sewing. Learning how to delicately apply heat to a wrapped object might even let you do a sort of molding with it.
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