Plastic Molding With Grocery Bags




I hated seeing all these perfectly good plastic bags go to waste, so I decided I would figure out a way to reuse them. In this instructable I'll show you how to use old bags to mold plastic parts.

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Step 1: Gather Materials

All you need is:

Plastic bags

A mold to cast

A large open space

Step 2: Preparation

Twist up a plastic bag and hold it with the pliers

Light the bag on fire


Step 3: Molding

After a few second molten drops of plastic will drip off of the end. Let these drip over your mold. Continue until the mold is full. It may take more than one bag. Let the plastic and the mold cool for at least five minutes

Step 4: Done!

Thats it! After it has cooled take it out of your mold. You might want to use a knife or a torch to smooth out some of the edges.

Don't forget to rate and vote

If you have any questions feel free to comment.

Enjoy responsibly!

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    267 Discussions


    Tip 1 year ago

    Hi! Just a thought based on something I saw in another instructable I forget the name of: If you put the plastic in regular cooking oil you can raise it to the needed temperature without having to worry about gasses and fumes, just toss it all in the oil (making sure it's clean first) and heat to somewhere near 200 degrees celcius. It should be reduced to a gooey consistency that can easily be squished into a mould.


    3 years ago

    this plastic is really cool but from experience with molding plastic, there are a couple of different plastics that are out there the most common one being hdpe in fact the bags you just melted are hdpe. the good thing about this plastic is the least toxic and should not release fumes if you dont overheat it. also overheating the plastic will break apart the polymer molecules and drastically weaken the material and will. the way i melt it is with a toaster oven set to 330 - 340 degrees farenheit and i put in a lot of bags at least 40 because each bag only gives you about 5 grams of plastic. and keep in mind hdpe plastic which is the same as the bags will not become liquid when melted which is normal it will become a sort of dough like consistency so you simply take oven proof gloves knead the plastic like dough reheat and then clamp it down between two sheets of plywood in my case i had a more dedicated mold i made with a rectangular baking pan and a cover i made of plywood that you can clamp down after about an hour of cooling i unclamped the mold and had a solid sheet of plastic which was completely unbreakable and is even stronger than wood. in additition to plastic bags there are many more things that are made of hdpe including milk jugs, detergent bottles, 5 gallon buckets, water bottle caps all of these can be melted down. if you look up "melt hdpe" on google there are many tutorials explainining the process better than me.


    5 years ago

    Mine just burned up no molten plastic


    5 years ago

    Is the plastic very rigid?


    11 years ago on Step 4

    It would be green if u use an oven if your on an green powerplant grid. like solar power or nuclear power.

    15 replies

    Reply 11 years ago on Introduction

    Wind, PV, and other solar are the only 'real green'. Nukes just change the problem and push working out a solution for it back a few years. Sofar the good folks on NV still don't want the nuke waste site in their state where the feds have built a nice 'disposal site' in a mountain. Anyone else want it?


    Reply 10 years ago on Introduction

    the fact that natural resources are mined out of the earth to produce the nuclear energy is the part that is not green. Killing national parks, chopping down trees and mining are not green.


    No it ain't, You won't be thinking that when one of the reactors mysteriously go KA-BOOM and kill thousands of people

    Here's a question. How many nuclear power plants are there in the world? About 400, and plans to build more. How many times has one had an accident? Seven or less in fifty years. How many times have you turned on the news to see a nuclear power plant disaster? Probably never. They can have accidents, but it happens very rarely.

    liliamarCeiling cat

    Reply 6 years ago on Step 4

    But when they do, thousands are dying. so, not immidiatly but even today a very high ratio of malformed babys are borne in tschernobyl and hiroshima.
    And again: the plants have to be maintenanced for 70.000 years. How long will it take until the next warlord is seeking a good aim? How long until the next earthquake? Naive.


    Reply 5 years ago on Introduction

    Chernobyl was right without the additional ts prefix! LOL! 3yrs ago my Niece and I took a train journey. Looking up our return trip on a location was absent from the drop-down menu of Scottish stations; Glasgow. 2008 I could hear the sirens of but never saw any of lots of 999 vehicles going to/from the city centre. *Ive just been shown imagery which strongly suggests 2 warheads aimed at us*. 2011 Re-telling my story of how after a shopkeeper pointed out the Till Total of the preceding customer was $9.11 I'd gone to an auctionhouse to find myself registered, Seller #911, I turned round to find I was standing in front of a man from 911 Emergency Breakdown. "Twin Towers" beer bottles/collapsing building Tom/Natalie; The Syndicate2 The sea level low camera angles...the large canister mime-lifted by one of the Santander red outfitted Hospital Dancers... Truth hidden within fiction.

    twopussezCeiling cat

    Reply 5 years ago on Introduction

    or they just keep very quiet about it, like you would if you'd just caused the immediate or 30yr-delayed deaths of millions of people or caused their babies to be born with serious genetic defects or who are sterile as adults :)

    Actually I have heard of the Chernobyl Disaster, very much so. But that was one event of only seven. And it was the direct result of people making very bad decisions, not of a lack of the reactors safety. These accidents are possible, just not very probable.

    You even said it! These accidents are possible, just not very probable.

    Even if they aren't probable, They can still happen

    unseen wombatthermoelectric

    Reply 9 years ago on Step 4

    well i hope you don't ever go out in a car, because even though it isn't probable, traffic fatalities HAPPEN. Or fly in a plane, or go swimming, or use the shower, or walk downstairs, or cross the street, or...

    lotusduckunseen wombat

    Reply 8 years ago on Step 4

    I think traffic fatalities are pretty probable, add other casualties and it's a real concern. Drive long enough and you will at least witness such an injury. But the worst case scenario in driving a car is causing a pile-up and causing the death of 10-40 people and perhaps many more injuries, the worst case scenario for any given nuclear power plant is much worse, and not just on-site, but cancer for everyone six countries downwind of you sort of bad news. Plants on lakes are one thing--we have a lot of nuclear power plants on the Mississippi river, like this one
    Terrorists don't tend to think in those terms, attacking symbolic targets primarily, but if we had a nuclear meltdown near the start of the Mississippi, the environmental and agricultural impacts could be really, really bad.

    Of course there are dangers in everything, but that's not an argument against caution. I use the stairs, but I keep my hand on the railing.