Introduction: How to "make" Plastic

Picture of How to "make" Plastic

I have always searched for a quick and simple way to make plastic. I have tried many but the one in this instructable the best I have found. It uses materials that you probably already have in your house,
it is fun to do and can be completed within minutes. I hope you will enjoy doing this instructable and will be able to learn something at the same time.

Step 1: Materials

Picture of Materials

Acetone is commonly used as a paint thiner and can be found at your local hardware shop or at

glass container
This can be an empty pot of jam or a beaker.

expanded polystyrene (styrofoam)
You can buy styrofoam cups or use any other piece of styrofoam you have.

safety goglesYou might consider using these because acetone can cause permanent eye damage.

Step 2: Prepare the Acetone

Picture of Prepare the Acetone

Open the canister of acetone and pour some acetone into the glass container. You don't need much, 1 centimeter should be enough for a little batch of plastic. If theres not enough you can always add some more later.

Step 3: Melt the Styrofoam

Picture of Melt the Styrofoam
Start by breaking your block or blocks of Styrofoam in pieces that fit into your glass container. Then take the pieces and push them into the acetone. Continue pushing Styrofoam into the acetone until the blocks you put in don't melt anymore.

Then wait one to five minutes for some of the acetone to evaporate. Wait one minute if you want it to mold the plastic and five if you want to shape it. The more you let the acetone evaporate the more solid it will be. You might even want to mold it while its still "liquid".

Here's a video that demonstrates the melting process.

Step 4: Other Usefull Info

Picture of Other Usefull Info

If you do not use the plastic immediately cover the container in which you put the plastic.

If your plastic becomes to hard to work with dip it in some acetone to make it soft again.

The plastic fully cures in about 12 hours.

Step 5: Safety

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Acetone is a very dangerous chemical, read the safety instructions before using it. You should never drink or inhale it. Also, do not do this project near any kind of flames because acetone is very flammable. Wash your hands after touching the uncured plastic or the acetone and don't do anything stupid. Do this project in a well ventilated area, preferably outside.

Here's an extract of the MSDS safety sheet: "May be harmful by inhalation, ingestion or skin absorption. Irritant. Liquid may cause permanent eye damage (corneal clouding). Contact with skin may cause defatting, leading to irritation. Long-term exposure may cause liver damage." Wearing gloves is a good idea, but you'll have to use butyl rubber gloves or some other kind of acetone resistant glove. For more information on chemical resistant gloves follow this link.

Disclaimer: I am not responsible for any harm done to you by your negligence or misinterpretation of this project and by using this information you agree to defend and hold me harmless from any and all claims, demands, damages, costs and liabilities.

Step 6: The Science Behind It

Picture of The Science Behind It

Polystyrene is a polymer made from the monomer styrene, a liquid hydrocarbon that is commercially manufactured from petroleum by the chemical industry.

The chemical makeup of polystyrene is a long chain hydrocarbon with every other carbon connected to a Phenyl group.

Expanded polystyrene (Styrofoam) is produced from a mixture of about 90-95% polystyrene and 5-10% gaseous blowing agent, most commonly pentane or carbon dioxide.The solid plastic is expanded into a foam through the use of heat, usually steam.

Pure solid polystyrene is a colorless, hard plastic with limited flexibility. It can be cast into molds with fine detail. Polystyrene can be transparent or can be made to take on various colors. It is economical and is used for producing plastic model assembly kits, license plate frames, plastic cutlery, CD "jewel" cases, and many other objects where a fairly rigid, economical plastic of any of various colours is desired.

When Styrofoam is added to acetone (a common organic solvent) it very rapidly dissolves, making it look like it is disappearing. The melted plastic can be recovered from the acetone to make hard solid Styrofoam plastic (polystyrene). In other words, you don't actually make plastic you just transform an existing form of plastic. The acetone sort of serves as a molecular "lubricant" between the polymer chains, allowing them to slide around each other. The Styrofoam becomes soft, releasing the air bubbles trapped in the foam, and the polystyrene ends up as a soft blob in the acetone. When the blob is removed and the acetone is allowed to evaporate, it solidifies into a piece of hard plastic.

Their are two type of solvents, polar solvents and non polar solvents. Bio-plastics will dissolve in polar solvents like water, while polystyrene will dissolve in non-polar solvents like acetone.

Let's consider two solvents that are pretty different in their polarities in order to explore this topic. Water, which we said is a polar solvent, dissolves almost anything that is polar, such as salt and many other ionic compounds. Water can't dissolve everything, though. Try removing fingernail polish with water and you'll see what I mean. Acetone, a solvent with some non-polar properties, is commonly used to do that job. Acetone is an effective solvent for all sorts of non-polar substances.

The resin identification code symbol for polystyrene, developed by the Society of the Plastics Industry so that items can be labeled for easy recycling, is 6. However, the majority of polystyrene products are currently not recycled because of a lack of suitable recycling facilities.
Hence, even tough this is a petroleum based plastic, you probably are helping the environment since you reuse a plastic that would usually go to waste and that would take thousands of years to decompose.

source: wikipedia


MarkH180 (author)2017-10-08

Done this with gas-appreciate the reminder Acetone works, also appreciate the science behind it. I do lost wax jewelry and lost foam casting of metals. I wonder if this would burn out of a mold in a firnace cleanly like was as this would be easier to work with on small, detailed items.

yonatonc (author)2017-09-14


georgew93 (author)2016-12-09

i have a 5 lb. bag of styrofoam beads. how much plastic would it yield?

jʎɐɹ-ɾ (author)2016-07-21

Hi! This is an interesting project. It's been a while. Have you been able to make anything useful from this material?

munir A chughtai (author)2016-04-28


Very Good instructable, Its very nice would you pleas instruct me which chemical should i include in this for waterproof my shirt.


munir Ahmed Chughtai

nerd12 (author)2011-12-06

i made some of this stuff recently and filled a short length of PVC pipe with it as a mold. the next day i pick up the pvc to find that the plastic had not dried and also the PVC was going soft! i think that acetone is a solvent for PVC but won't dissolve it. i will experiment more and let you guys know.

PS. the pipe was standard 20mm plumbing PVC pipe

smoak (author)nerd122011-12-26

Acetone breaks down and reconstitutes almost all plastics. You could also use Acetone and Legos. Acetone and any ABS plastics will cause the plastics to melt essentially. That's why the PVC was going "soft". If you had more acetone there it would have melted it and could have caused a very large mess. I wouldn't recommend this type of "plastic" for injection molding.

nerd12 (author)smoak2011-12-31

it went only a little soft. i actually tried to shove this stuff(acetone + thermocol) into a paper mold but even though i had painted it with resin it tore. any suggestions as to mold it? also i want to make a look alike spartan spear for a costume out of 3/4 in CPVC piping but i do not know how to shape the blade into one. any ideas for molding this?
please respond.

paqrat (author)nerd122012-01-26

Could you line your paper mold with aluminum foil?

TheRoyalJester (author)paqrat2015-12-18

Just use a plaster mold, its much simpler.

nerd12 (author)paqrat2012-01-27

the mold tore, so i don't think it would make a big difference. this would work though if it was just sticking.

mary.andrade.7399 (author)nerd122015-03-22

Olá , li seu comentário e vim te dar uma ideia, que tal você usar argila para criar seu molde. Após pronto e seco o molde pode ir para queima, fica resistente.

Fredfly (author)nerd122014-06-01

the mealting works with most solvents eg terps petrol and PVC is also plastic so it would mealt

TheRoyalJester (author)2015-12-18

Good instructable, but I really want to stress the FACT that you should ALWAYS AVOID contact with acetone. That is not safe for contact with eyes, and accidents happen.

gabriele vargiu (author)2015-07-14

Thanks for this instructable, i found it quite accurate and wanna ask you if is it possible to add some dye.

Yes, but you would have to make sure it is safe to mix with acetone first.


I don't know whether you can add dye, but when I do it and I want to add color, I use colored styrofoam like the red ones and sometimes green or blue in meat and vegetable packages in plastic wrap.

orangecreamsiclecat (author)2015-09-04

Mine always take forever to harden, so I put it in the freezer for a couple days. I use it as a clay.

ok1987 (author)2015-09-02

MandalorianMaker (author)2015-04-16

This is how you can make napalm, you can also do it with gas.

MacMatthias (author)2014-04-04

Ccan you add black dye?
How long does it take to harden?
How hard does it get?

critopadolf (author)2014-02-17

I did this but the inside of my ball won't dry... How can I fix this?

kbarthoulemuen (author)2014-01-12

What does the MOHs rating look like on this?

LiftAndLove (author)2013-01-09

Umm, idk if anyone else noticed but he made 'napalm' along with his plastic *-*

InTheory (author)LiftAndLove2013-09-20

Yeah, don't keep that near an open flame...

JokerIsAwesome (author)2012-10-03

Can I use this kind of plastic for making "teeth" to hide my braces? And can I use clay for the mold of the teeth? Help would be gladly appreciated. :)

Lia76 (author)2012-09-03

I can make my own plastic products by using some recycle plastic in my home. I am using the step that just same like the "plastic injection mold machine". I can make any think with different colour and I can make it just a few minutes.

radznjason2011 (author)2012-08-30

Is there an instructible which shows actually making things from this kind of plastic? I made some as an experiment but it was so sticky it's hard for me to imagined making anything useful from it. I can't find a site anywhere showing how to use it.

Suspect_Bronies (author)2012-03-11

You mentioned how the Acetone could damage your eyes. I'm wanting to make a pair of cosplay glasses with this how-to, and I was wondering if wearing said glasses would damage my eyes at all?

I'd say that it's safe. After all all of the acetone has already been evaporated, but I'd wait a day before putting them on, just to make sure.

Tonyod (author)2012-06-09

You need to look up Material Safety Data Sheets for any chemical you use they are very practical, giving lots of information about the safety aspects of solvents and other chemicals. Acetone can remove some of the oils and fats from your skin . There is also flammability issues as you all know. All industrial chemicals have some issues it just depends how you use them. MSDS's are full of practical info, just google them

kwazai (author)2012-05-28

adding gasoline is do it yourself napalm.
wonder if the 'coffe cups' make a better plastic with acetone than the 'packing peanuts' do?

Nagarok (author)2011-08-27

Looking at the science behind it, you theoretically don't need to use acetone to make this react.

You just need a non-polar solvent that could be potentially less dangerous, but they may not be as readily available as acetone.

squiggy2 (author)Nagarok2012-02-08

I had this thought myself, but acetone is good because it evaporates quickly. I Made a test batch of this stuff about - 10-15 millilitres - using turpentine. It dissolved well enough, but 2 weeks later it's still squishy.

knoxarama (author)2012-01-27

Yeah, I was too lazy to find acetone so I just used gasoline

Landon Sullivan (author)2011-12-11

Congratulations, you now have a napalm-esque substitute.

nerd12 (author)2011-12-06

i tried to take a blob of hardened plastic(this stuff) and melt it to pour into my mold. i still can't get the smell out of my lab and the stuff didn't work out. took ages to even get gooey.

nerd12 (author)2011-12-06

i tried to force this stuff into a mold made from cardboard made with the help of pepakura. the paper completely tore. any one have any ideas on how i can make similar molds and perhaps inject the plastic into it?

de.das.dude (author)2011-11-28

how is this for moulding PC case parts for mods? is this stuff hard to paint? my thoughts are solvent based paints should work.

Slon (author)2011-11-27

Polystyrene solution in acetone. Polić doughy mass. Then. Add gradually, stirring with turpentine. Get a totally transparent thick liquid. How do I use? Think for yourself.

Slon (author)2011-11-27

Polystyrene solution in acetone. Polić doughy mass. Then. Add gradually, stirring with turpentine. Get a totally transparent thick liquid.

stu2theMax (author)2011-09-07

You do know this is how u make napalm right?

nerd12 (author)stu2theMax2011-10-26

you make napalm by adding aluminum soaps to petrol (gasoline)!
this would be flammable due to the acetone and the drying plastic would be like napalm (sticks 'n' burns) but not when dry. where did you get that idea from?

stu2theMax (author)nerd122011-10-26

I was just experimenting when I realized the common ingredients. There is an easier way to produce napalm tho. I believe someone even made an instructable how to do so. Which surprised me. Just be careful. Napalm can be very useful if not used for its original purpose.

nerd12 (author)stu2theMax2011-10-26

How are the ingredients common?
Napalm=Gas+Al Soap
weird plastic=Acetone+Styrofoam

i know that you could also use gas as the solvent but 2 things- gas is more flammable and it rather volatile as compared to acetone.
here acetone is used instead of gas

(PS- Textbook explainiation for 'volatile' means it evaporates easily, not explosive but often is.)

stu2theMax (author)nerd122011-10-26

A styrofoam does the same thing when acetone eats it. Stop questioning me and try it both ways if u don't believe me dubie. Then talk to me about what I don't know. :)

nerd12 (author)stu2theMax2011-10-27

i though this site had moderators on language. i am betting you are an American.
napalm, when lit almost explodes then starts to burn. do you really think i want to go to hell directly?
this 'might' be an explosive but it won't be napalm. it will be somthing else.

useraaaaa (author)nerd122011-11-17

"napalm" is sticky flamable goo

so acetone + styrofoam :-)

also you can sniff acetone :-)

Arano (author)useraaaaa2011-11-17

napalm contains by definition gasoline and a thickener...

nerd12 (author)Arano2011-11-17

Which is where the Al Soap comes in...

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