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Homemade Plastic

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Step 5: Mold!

At this point, you're ready to do whatever you want with the plastic.

It will take about two days to cure, but if you're using a mold where it cannot easily breathe, it will take longer.

One thing to watch out for is that the casein will warp when it's drying, especially if you have it rolled out into a sheet. It's best to put a weight on it. Watch out, though, because it will seep a milky-vinegary scented liquid into whatever is holding it in place. I used a heavy programming book...and it now has a funny smell to it. Awesome.

For my project, I just need to roll the casein out and let it dry.

Lay another sheet of wax paper over the casein. Use a rolling pin to spread it out. If you didn't dry it too much in the previous step, it should roll nicely, without many cracks or chunks.

Finally, I pressed it between two sheets of aluminum foil, and curved it across the bevel I'm using.

Give it a few days to dry, and it'll be ready to go. This is critical. Depending on how you wrap/mold your casein, you may find it takes more than a week to dry. Wrapping mine in foil took two weeks to get remotely dry. As is expected, the thicker it is, the longer it will take to dry.

I should also note that if you're making a flat piece like I am, the plastic will curl if you remove it from its mold before its dry. I made this mistake with this project, and ended up with a piece that was unusable because it curled.

The final product is quite rigid when it's thick (1/8 inch or thicker), moderately pliable when it's a little thinner, and brittle if it's paper thin. It's also sandable and paintable.

Go forth and have homemade plasticy fun!
 
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sudanione2 years ago
how can make it transparent
You can't.
fqian yan2 years ago
will mold grow on it in the process of drying?
billraymond2 years ago
Are you sure this is truly casein?? My understanding is that casein is precipitated from milk by rennet, not heat. Heating whey with vinegar or other acidifier creates ricotta, which is not a cheese, as it contains no casein, but is rather the precipitated albumin and other (not casein) proteins. Galalith is made from casein and must be fixed in a formaldehyde bath; it is not moldable.
dodo915 years ago
can you add food coloring to make diffrent color plastic? i want to make this for my little brother, but white would be BORING!
You sure can, just add it before you start the cooking process!
This is pretty cool and i think im going to make a few thin sheets for airsoft myself but im going to use them as targets hopefully if its as brittle as you say it will shatter nicely.
You should use Sugar Glass, heh - it's quicker to make. ;)
skooterv25 years ago
I play airsoft a lot and I play with some people with guns that hurt pretty bad...and this may sound weird but I was wondering if I made this thick enough do U think it could withstand some pretty hard blows like from guns shooting at 400+ fps... TYVM
Coffeebot (author)  skooterv25 years ago
It might work, if you make it thick enough. It's pretty brittle in thinner layers, and as such, wouldn't do well as body armor.

As for "making it stronger" (your note below), you could possibly add some fabric, of some sort to strengthen it.
btw is there anything I could add to make it stronger?? And if u could e-mail me back on this I would greatly appreciate it
yahoo235 years ago
How strong do you think this will be against drops, bumps, and scratches? I was thinking of maybe making a case out of this for my iPod or phone. Any ideas? Or would it be easier just to buy one from a store?
make the case then to toughen it up put a couple of coats of pva glue on it, itll stop scratches and give resistance to shock for your phone :) i like cheeze :)
Coffeebot (author)  yahoo235 years ago
I wouldn't recommend this for anything that will see frequent and potentially rough use. You would probably be better off just buying something from the store. I know there are some products available that you could buy to make your own case...but I wouldn't know where to start looking, honestly.
Good tutorial, but I cant find simmilar things. Can anyone put some links with simmilar sites or articles? I am intrested in home - made materials... Thanks
Coffeebot (author)  vedran_setka6 years ago
Unfortunately, I don't know of much else. I'd say just try googling for "homemade X", where X is whatever it is you're trying to make.

This plastic is actually featured in quite a few elementary science projects. <cheap plug>
I actually learned about it from a nifty book "Sneaky Uses for Everyday Items" (Buy it from ThinkGeek).
</cheap plug>

I was surprised that this hadn't been posted before on Instructables.
same here! it is better or instructables. that book has alook of kinda childish things it.
For the step where you strain it, and the step when you're pressing out the excess liquid, you probably should use cheesecloth. That's pretty much what it's designed for - it's pretty cheap and you can get it at many supermarkets in the section that sells kitchen utensils. Wrapping it up in a cheesecloth will also enable you to squeeze it harder and get more liquid out. For the stingy, since you're not planning to eat it, you could probably also use any old piece of cotton like an old T-shirt.
tonymaye5 years ago
brilliant, when you're done with using what you've made you can eat it, compost it, or give it to the dog!
quntmphscs5 years ago
Where is the final product? I wanted to see it actually made into something and hold stuff. This is EXACTLY how I made soft cottage cheese by the way, except for the pressing part. I let the "curds" drain in a cheese cloth (or similar cloth) set inside of a strainer and let it sit one hour. The stuff that drains out, the animals will drink it like crazy. The other stuff refrigerate and add whatever you want. Pepper, berries, olive oil & spiced. Eat like cottage cheese, but it's better. 1/2 gallon milk, when boiling on the sides (called scalding) add 1/4 C Apple cider vinegar and stir. Let it sit in the pot till it cools. Then strain.
xlioilx6 years ago
What kind of plastic is this? I think that it would biodegrade very fast as its not really a polymer this is more like making old style glue then plastic. I seriously doubt that it melts very well. The odor would be nasty like burnt fingernails. Most plastic smells sweet when its melted, or sometimes it smells like ammonia. It just depends on the type of plastic, blowing agent if any and coloring. Seriously though if you want some plastic for a project that will melt right, just find a clear container and grind it or cut it up. Then put it through your extruder that you have hooked up to the 480 volt transformer in your garage. That would work much better if you wanted to make something out of plastic. Trust me I work with injection molding machines every day. Still it is a nice harmless science project for the kids.
budsiskos6 years ago
can you melt it
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