Introduction: Useful & Durable 7 Strand Rope (cord) From Plastic Shopping Bags

About: Just your typical Evil Mad Scientist, constantly thinking of new inventions to subjugate the world with! I'm big on hydroponics, electronics, and small portable nuclear fusion power plants. I just go crazy o…

I basically combined two other instructables that I've read in the past. One was making plastic "yarn" out of plastic shopping bags.  I guess people here are calling it "plarn" now.   The other was braiding cordage/rope from smaller strands of string/thread/cord/rope. Both techniques I've found highly useful with a lot of my projects.

With this one I combined both and made a very useful cord/rope out of mere shopping bags that were going into the recycling bin anyway. The end product is pretty handy. It's very strong, it's waterproof, and it's practically free.

I'd be willing to bet that if I took 7 of these ropes (that I made here) and wove them into a larger rope, I could easily use it to tow a car!  No seriously.

Now a few people have made ropes from plastic bags here on instructables, but they twisted them.  This project makes a much more aesthetically pleasing braided 7 part rope. 

You could use it for pet leashes, fishing stringers, shoelaces, camping gear, jumping ropes, or even a rock sling.  The limits are practically endless. It would make a great boy-scout/girl-scout or school project too. For ideas with what you can do with the rope just search here at Instructables for "knot" or "decorative knot". My personal favorite is "Monkey Fist"... look it up!

So make your own and please let everyone know what you used yours for!  If you send me a picture I'll post it on this instructable!

Step 1: Materials List

1 or more plastic shopping bags
1 small piece of cardboard
1 pair of scissors

Step 2: Science (Math) Content

Ok, I have to admit that I'm really bad about converting the stupid English measurement system to the much easier to use Metric system.  So if you are reading ANY of my instructables and I forgot to convert, PLEASE DO NOT hesitate to point it out!

I want to give everyone an idea on what they can expect.  Your project will differ a bit depending upon how thick you cut your loops, how wide your bag is (which effects how long the loops are), and how many strands you decide to use in your braid.  So keep that in mind.

I wish more people who write instructables did this kind of thing!

So on to the Science/Math!! Or MATHS for you English people!  Let's run some numbers!

I cut my loops with a width of roughly 3/4 inch (roughly 20mm).  The length of the loops were roughly 18-19 inches long (45cm-48cm).  Using 7 strands (of 18-19 inches, 45-48 cm) in my weave I got approximately 8 inches of weaved rope (20cm), but this was un-stretched.  When I stretched it, it lengthened out to 13 inches (33cm).   In other words each set of 7 loops I get 70% of that length in weaved rope.

I am getting about about 20-22 loops per plastic shopping bag.  Divide that by the number of strands in your weave (in my case that is 7), and I get just about 3 sets of 7 per bag.   Now I multiply that by 13 inches (33cm) of weaved rope per set of 7 loops and I get 39 inches (3.25 feet or 99 cm, so approximately 1 meter) of rope per plastic bag.

Now you should have an estimate of how many plastic bags you will need for your project.

Step 3: Cut Your Plastic Loops From the Plastic Shopping Bag.

Start by taking a plastic shopping bag, flatten it, and fold in the sides (pic 1).  Then fold one side over (about 3 inches worth) toward the other side (pic 2).  Continue doing this until you have a plastic bag strip (pic 3 & 4).  

Starting from the bottom of the bag, cut a strip about an inch thick, discard this piece because it's the sealed bottom part of the bag.  What we want is loops so the next strips will be loops.  Now cut strips, I cut strips about 3/4 of an inch thick (about 20mm).  Continue cutting strips until you reach the top of the bag.  I got about 20-24 strips out of a bag.

Step 4: Expand Your Loops and Connect Them.

If you take your cut strips and expand them out, they should make a bunch of plastic loops.  Mine were about 18-19 inches long when expanded (or 45-49cm).

Take two loops and connect them together, as shown in the pictures.  Then pull the two loops tight and you've got a plastic "sring" which is roughly two loops long.

Now you need to make 7 more of these "strings".

Step 5: Tie Your Plastic Bag "strings" Together.

Take all the 7 ends of your 7 strings and tie them together in a simple half hitch knot as shown in the pictures.

Step 6: Make Your Circle Loom.

I cut one of the top panels of a cardboard box off with my scissors.  Then cut it in half to make a square.  Then I cut the corners of the square to make an octogon.   Cut slits into the flat size of the octogon about a half inch toward the center.  Then cut little triangles off the openings of these slits to make threading your strings easier into these slots.  Next using the point of the scissors poke a hole large enough for your seven strings to fit through.

Step 7: Set Up Your Circle Loom.

Now taking each seperate string, thread them each into one slot.  Notice you will have 1 slot empty, this is needed in order for us to begin weaving the braid.  If things look a little messy to start with, don't worry about it.  Once we start weaving the braid it will look better.

Step 8: Weave Your Strings Into a Rope or Cord.

Hold your circle loom as shown in the first picture, with the unused slit towards the top (but actually just a bit to the right.  Now clockwise from this open slit, skip 2 strings then pick up the third one, pull it out of it's slit, move it up to the open slit and secure it.

Now you just repeat this process over and over again to weave your rope.  Every so often slightly pull on the end of the weaved rope from the bottom.

Twisting the strings while doing this produces a neater final rope.

When you get low on what is left of your strings, add another loop worth of length to all 7 strings. Don't worry about all seven lengths ending up being the same when you add loops. The longer you do this the more off they will get.

Experiment with changing the color of plastic bags you are using.  Generally just having one of the 7 strings a different color, won't really produce a noticeable change.  So I'd suggest changing the color of 2-4 of the 7 strings.

Step 9: Advanced Weaving With the Circle Loom.

Now I found a slightly faster way to do this weaving.  Once you've got the simple method down (step 8), then you can try a slightly more advanced method.

Holding the open slit in the upper right.  Weave up (the 3rd string clockwise) with your right hand.  Then turn slightly clockwise so the open slit is in the lower left hand, and weave DOWN (the third string clockwise from the open slit) with the left hand.

Once you've got this down, it goes fairly quickly.  In an hour I was able weave 3 plastic loops worth of length.

Again when you get low on what is left of your strings, add another loop worth of length to all 7 strings.  Don't worry about all seven lengths ending up being the same when you add loops.  The longer you do this the more off they will get.

Step 10: Plastic Rope!

When your rope is long enough tie off the ends the same way we did when we first started.  Step 4.  

I'm still working on mine, because I'm thinking of weaving a belt out of it.  Which will be another instructable entirely.

Update:  I've got about 15 feet to date (4.5 meters) (10/20/2010)

Step 11: Things Made With This Plastic Rope (STAY TUNED)

Ok, I have a problem in that I get so excited in making things, that I don't take pictures while I'm making it.  So I have to make a second one to take pictures of the various steps from which I can write an Instructable on.  


Well it happened to me again!  I got inspired by this Instructable  and used my method of making plastic rope to make a rock sling.  I spent an entire weekend weaving the darn thing because the following weekend we were going camping and I'd have an opportunity to test it out.  I just wish I would have snapped a picture of it before we did.  

The sling worked great and looked pretty darn cool, if I do say so myself!  It just so happened that one of the people that we went camping with (and I didn't know that until we got there) was an experienced rock sling guy.  I had tried it myself (I've never used a rock sling before) and quickly realized that there was a skill that I'd need to develop in order to get any good at it.  Well the one gentleman that we went camping with asked to try it out and boy can I tell you he could whip those rocks further and faster than I could.  He could even hit near targets with it.  Unfortunately he was so good with it that one of the other guys that went camping with us wanted to try it out and learn it too.  Well we were near a lake and he was practicing slinging rocks out into the lake.   Quite to my disappointment he let go of both ends and I just got to see my nice new sling fly out into the lake and sink.  We even took the boat out to see if it might have floated but we were unable to recover it.

I knew I would have to make a second one in order to show here and to write another, separate instructable on.  So stay tuned and I'll have pictures of my second version of rock sling in another couple of weeks.

UPDATE:  I have about 1/2 of the Mark II done.  I should have the rest of it done in the next 2 weeks.


I'm also still working on weaving a belt out of my plastic braided rope as well, but it's just taking me a while to get enough of the rope made to weave the belt with!  I've got about 8 feet of it made so far.

BELT UPDATE :  As of 10/19/2010 I've got just over 15 feet of rope made.  Instead of watching the insipidly stupid reality television shows that my wife INSISTS on watching.  I just sit there and weave my rope.  All the while uttering a mechanical; "yeah", "oh", "ok", or "hmmm" so that she actually believes that I'm listening to the mindless drivel, even though I have my mp3 player playing an audio book to my earbuds.

If this Instructable inspires you to make something, please take a picture of it so that I can post it here!

BELT UPDATE 2: I have about 25 feet of this rope made