Instructables

Very strong shopping bag rope - no tools needed

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I started thinking about rope recently after Mr. Balleng posted his rope making instructable.   I also remembered this old instructable in which they made a rope from shopping bags using a giant twisting device made out of bicycle parts.  Then I thought, why do you need to twist it?  I think twisting makes sense if you are using a very fibrous material so the fibers can kind of grab together and get intermeshed.  But plastic shopping bags aren't really fibrous, so maybe you don't need to bother with the twisting.

So I came up with this way to make a very strong rope.  The cool thing about it is you don't need *any* tools to make it.


 
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Step 1: Materials

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plastic grocery bags - lots of them.  You can get a lot by asking on freecycle.org.  I posted a message asking for them and got enough plastic bags to make 150 feet of rope!

Figure on approximately 2 bags per foot of rope

optional: scissors




Step 2: Flatten the bags

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Straighten out the bag and flatten it out as indicated in the photos.




Step 3: Tear through the middle

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As promised, no tools needed.....

You can use your fingers and tear them vertically from bottom to top very easily as demonstrated in the video.





Step 4: Optional tool: scissors

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okay, if you have some scissors around, you can just cut them en masse

Step 5: Make strands

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Chain each half section of bag together with the next as shown in the photos.

Tear a tiny hole in the side near the bottom seam.
Thread the handle of another section through the hole you just made.
Thread the body of the other section through it's own handle you just passed through.
Pull it tight.

Repeat until you have about 5 or 6 half bags connected together into a strand about 6 feet long.

Make at least 2 of these strands to get started. It helps if they are contrasting colors, but not especially necessary.







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SwordSlash30011 months ago
That is awesome! Now i can use all my grocery bags and I want to try and test its strength! Awesome idea! :)
I did this in a grocery store, when I was bored out of my mind. You sure brought it to a higher level. Nice 'ible
Captain44311 months ago
WTG --- Get Job.... For your weight testing I might suggest taking a 3 ft piece of threaded rod bending it over to from an eye on one end and then get a nut, a washer, and a piece of some material (Block of wood) big enough to hold everyday weights on the threaded rod... Then hang the rope from whatever you want, attach the eye hook and build up the weight's until it breaks.... Just a thought ... Good Luck....
foobear (author)  Captain44311 months ago
Thank you for the positive feedback! And yes, I do need to get a job - heehee
Captain443 foobear11 months ago
LOL...I am sorry I dont know where the word "GET" came from...
It was supposed to be "Great"....
Like in WTG --- Great Job....

Again I thought it was a Job Well Done and I am sorry for the type-o

Good Luck I hope the weight testting works out for you....
bob303012 months ago
I've always liked recycle/reuse projects. Thanks for posting.
foobear (author)  bob303011 months ago
thank you for the positive feedback
gerflash12 months ago
Wow! Good idea! Now I know what to do with that 5 year collection of poly bags that I just couldn't throw out! And yes, got to watch out for excess exposure to sunlite.
foobear (author)  gerflash11 months ago
glad to help
kyluddy11 months ago
This is a great idea! You did a great job and it's a perfect idea! Its a great way to recycle and it's just plain awesome. Really good job.
foobear (author)  kyluddy11 months ago
Thank you. Your comment is 100% positive and I really appreciate that.

I like it.

Woodlandboy4610 months ago

hello i Think is an amazing idea, i got exited and jumped the gun and didn't finish reading the instructable and started doing a three strand braid do you think it will be a problem

foobear (author)  Woodlandboy4610 months ago
that's cool that you were excited! I'm sure a three strand braid will be very strong as well
devinnov2810 months ago
i will try this now!
Light_Lab12 months ago
As many people have mentioned all plastics are degraded eventually by sunlight and/or oxygen. The degradation is usually limited by UV absorbers and antioxidants in plastics used outdoors. Plastic bags are expected to breakdown quickly in the environment so little or no protection is added. In fact we have in Australia some starch based bags that break down very quickly. Depending how you use the ropes and where you leave them tied in the environment it might not be a bad thing.
As this site has a global audience I should mention that the polymers used to make plastic bags varies considerably throughout the world and in different applications. HDPE, LLDPE, LDPE, starch etc etc each plastic has a different modulus (stretchiness). The plastic in the picture appears to be HDPE so it is quite rigid.
The reason the bags used tear easily in one direction indicates that the blow up ratio wasn't balanced when the bags were made. It is a manufacturing defect that might not be consistent with different bags.
foobear (author)  Light_Lab11 months ago
Thanks for this information I found that I was able to do the bag tearing trick with several different varieties of bags from different stores. So maybe it's a defect, but it is a common one.
Light_Lab foobear10 months ago
It is a common defect, even our older polymer banknotes here in Australia can develop linear splits in use. It is more difficult to perfectly balance the blow up ratio in rigid plastics. Ultimately the desire to maximize production wins out and the film ends up orientated in the machine (take off) direction. Therefore I would expect that the easiest way to tear is mostly from top to bottom (or bottom to top) but not across the bag.
Ezava211 months ago
melt rubber on it caution it will smell
spark master12 months ago
This very nice, but remember these bags do degrade in sunlight. can take years or months, don't depend on your life with one. A Hammock can fail and smack you head first on hard earth!

just a thought
foobear (author)  spark master11 months ago
sobering advice taken thanks
Your welcome! I just happen to notice the bags did that. Relatively fast depending on quality of plastic, type of plastic, color, biodegradability as per manufacturer.

They will degrade indoors as well, just much slower. The theory is in a land fill they break down, sad part is they really need sunlight to do it fast enough to be useful in a landfill.
HibbityDibbity12 months ago
To test if it will hold your weight, you can tie a loop in one end and tie a length to a rafter/tree branch/etc. so that the loop only hangs 6" or so off the ground, then stand in the loop. I suspect it would hold your weight with no problem, as the tensile strength of those bags is pretty impressive, though I agree that I certainly wouldn't use it in a situation where life and limb were at stake. I also would not use it outside for a long time, as UV light would degrade the material. could be really great for a lot of applications around the house though! Excellent re-use of materials, and very creative!
foobear (author)  HibbityDibbity11 months ago
this is a good suggestion thank you
It is a hard-learned suggestion. A couple good buttock bruises will make a fellow devise some solid risk-management skills.
This is cool
foobear (author)  danceworkshop_311 months ago
cool
kalpeshswani12 months ago
Hi Nice work !!
One Error , quote in your bio is by Mahatma Gandhi (not ghandi)
"Whatever you do will be insignificant, but it is very important that you do it." - Gandhi

foobear (author)  kalpeshswani11 months ago
thanks for noticing
Kevanf112 months ago
Try Freegle.org in the UK to get hold of loads of plastic bags. Freecycle is dead in the water over here but networks like Freegle and Freeworld-Recycling have filled the void and gone even better.

Excellent 'ible', well done. You could also use this rope as a bird scarer in a garden. Just snip some bit off the sides so that they flat around in the breeze and string it around your plants that you don't want the birds getting at...
foobear (author)  Kevanf111 months ago
good suggestions, thank you
Gadisha12 months ago
Cool idea, thanks for posting this! :)
foobear (author)  Gadisha11 months ago
yw thx
grapenut12 months ago
I always love a simple ible. The video clip was quick and effective. Had I been left to interpret the still photo I would have been lost...
foobear (author)  grapenut11 months ago
glad the video was clear!
Very impressive... Does it stretch much? Also, for testing, you could tie some milk gallon jugs and slowly pour in water till it breaks. Just a thought for you!
foobear (author)  assemblyrequired1 year ago
It does stretch to a point, but once stretched it tends to stay stretched out. That's an interesting idea. I'm thinking a 5 gallon bucket, attach the rope the handle, hang it high from a tree, add water till it fills up, see how long it can stay there. Good suggestion, I think I will try it.
ctdahle foobear12 months ago
Neat idea. I started braiding a rope this morning and the kids took over.

Not sure about your testing scheme...5 gallons of water is only about 43 pounds. I think we'll just tie the "rope" to the cross bar on the swing set and use it to suspend a plywood disc about a foot from the ground. I'll sit on the disc and then the kids will pile on too and if it breaks, we will all fall in the sand and have a good laugh.

Be aware that plastic grocery bags photo-degrade pretty quickly, so if you use them to weave the rigging of your desert island escape raft, be sure to collect spare bags for repairs!
foobear (author)  ctdahle11 months ago
well, I meant to imply multiples of 5 gallon buckets. We don't drink milk around here, so ... gallon jugs are hard to accumulate. cheers
ccronkhite foobear11 months ago
Use it to hang several buckets filled to the same weight in different locations. Hang one outside in direct sunlight, one or more in varying amounts of shade and then another as a control subject hung inside where it will get little or preferably no light. Then you just have to check them periodically to see how long it takes each to break.

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