# Polypropylene slingshots



## Rathunter (Feb 14, 2014)

I have access to a decent amount(more than a pound) of polypropylene chips(roughly 1x1")

Would it be worth melting them to make slingshots?


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## Sunchierefram (Nov 16, 2013)

I've heard that polypropylene's pretty strong. So I'd assume that if you were to somehow make a slingshot with it, that it would be strong enough.


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## parnell (May 20, 2012)

I know someone who knows plastics will be able to answer. One thing is polypropelene safe to melt?


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## Sunchierefram (Nov 16, 2013)

Well, I've done some online research. I think it melts at 320 degrees Fahrenheit, if I remember right. But I didn't really find much else about melting it. So you might be able to melt those down. But I would do it outside and keep a fire extinguisher handy just in case.


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## Sunchierefram (Nov 16, 2013)

And just wondering, where did you get that many polypropylene chips?


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## Rathunter (Feb 14, 2014)

well, you ever heard of Arnold Palmer Iced Tea(50-50 lemonade and tea)?

My family loves it.

We go through ~1 gallon a day.

it comes in these really thick walled jugs. They are polypropylene- it is stated on the bottle.

I like to use them as targets for various things. When I am done with one I smash it up with a sledge and put it in a trash bag.

I save them because I know I will eventually find a use for them.

And polypropylene is bloody expensive when bought new. I might be able to sell the chips if I get enough. I do wash them, else the bag would stink.

I wonder if is more dangerous than melting pine pitch to fill torches?

that stuff is incredibly flammable. Worse than gasoline when it is molten.


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## Imperial (Feb 9, 2011)

omg ! that half tea is awesome ! i like to take a couple drinks out of the jug and drop in some jack daniels :drinkup:


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## parnell (May 20, 2012)

I would be more concerned about it putting off toxic fumes than flammibility. That is why Hdpe is a good choice because it doesn't put off fumes.


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## flipgun (Nov 14, 2012)

According to Wiki, it degrades from heat and UV. So I am guessing not so much good. :twocents:


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## libel (Jul 1, 2013)

Usually there are other polymers in the pp mix to help it hold its shape when it's formed because its done at higher temps. They usually make pp harder but a bit weaker. They may also give off questionable byproducts as they are heated so do this outside. It's a bit trickier to melt because the temperature range in which it's usable is very narrow and different depending on it's composition. It's also stickier than pe.


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## Dr J (Apr 22, 2013)

Really nice!


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## BlackBob (Mar 8, 2013)

Only thing I'd be concerned about is the fumes, how toxic will they be.


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## Dark (Aug 24, 2015)

Why do you think that more toxic polypropylene than polyethylene?

In my country, polypropylene pipes used for plumbing. When welding them has a sharp smell, but I have not heard of cases of poisoning during the installation of pipes


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## funny1048 (Jul 21, 2015)

i tryed to work with polypropylene and it actually was a success some other bottles also are polypropylene such as translucent medicine bottles and some other containers make sure you use polypropylene thats only used for bottles and is not colored it should look translucent. i tryed melting caps that were made out of polypropylene and it had a bad smell probably because the polypropylene for caps uses a different grade of polypropylene that flows better but releases some fumes from additives or colorants. for my test with polypropylene i found an old electrolyte drink bottle and i cut the polypropylene into little pieces i put it in the mold and clamped it down then i put it on my lathe and it actually worked really good and it didnt have any kind of odor as long as you use polypropylene from bottles it also was extremely strong maybe even stronger than hdpe i will put a picture up when i get a chance


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## Northerner (Nov 9, 2010)

I have several frames made from polypropylene (recycle #5). Mine were all made from a 5/8" thick cutting board so I didn't need to melt. Some of the frames are a couple of years old and still working fine. It cuts easily with a jigsaw and makes a strong frame.


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## Slingshot Silas (Apr 4, 2013)

Rathunter said:


> I have access to a decent amount(more than a pound) of polypropylene chips(roughly 1x1")
> 
> Would it be worth melting them to make slingshots?


FUMES!!!

Bloody biggest Squirrel I have ever seen! He's-------round. Livin' the good life, and it's paying off big time!

FUMES!!! Melt outside and don't be smelling the fumes. Yeah, what they all said.

Large Squirrel!

Yep, he's a biggun!!!

View attachment 86720


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## Slingshot Silas (Apr 4, 2013)

Uh Oh,

Lost Picture!






*THAR SHE BLOWS!!!!!!!!!!!*

Better face, and body than my Girlfriend!!!

Giggity!

SSS

:woot: :woot:


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## Arnisador78 (Apr 10, 2013)

Slingshot Silas said:


> Uh Oh,
> 
> Lost Picture! Squirrelfriend.jpg *THAR SHE BLOWS!!!!!!!!!!!*
> 
> ...


wow! Lmao


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## brucered (Dec 30, 2015)

I picked up a couple decent sized cutting boards, 3/4" thick for $15 Canadian. I'll be able to get about 8 frames from each, so $2 a pop.

So far I've made Poly versions of some of my favorite frames that I already had in 5/8" Baltic Ply.

I took a hammer to the board first, before shooting, it seems rock solid and only leaves and impact imprint. A video is shown below, seems like it will take fork hits without damaging. I'm going to hang a couple scraps tomorrow and fire at them from 5m with some 3/8" steel, to see what happens.

So far, so good, no issues. Easy to cut and work with on my scroll saw, routing edges, drum sander and finishes smooth and easy. They take about 45 min from start to finish (laying out pattern to final buffing of edges and band grooves). If nothing else, they will allow me to explore frame styles before investing money or time making them out of other materials.

Should I be worried about this material for Slingshots?


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## brucered (Dec 30, 2015)

Here is my impact test results.

Braced target, 5m, full draw, 3/8 steel, 0.30 latex 3/4".

It held up nicely, left an indent but didn't crack, chip or break.

I'm happy and confident to shoot them now.


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## Quercusuber (Nov 10, 2011)

brucered said:


> I picked up a couple decent sized cutting boards, 3/4" thick for $15 Canadian. I'll be able to get about 8 frames from each, so $2 a pop.
> 
> So far I've made Poly versions of some of my favorite frames that I already had in 5/8" Baltic Ply.
> 
> ...


AWESOME designs!!!!

That should be hard as nails.

Cheers ...Q


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## twang (May 10, 2015)

how did you round the edges? with a router?


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## brucered (Dec 30, 2015)

twang said:


> how did you round the edges? with a router?


The first couple I did by hand with a file and then sanding pads. It was OK, but not rounded over enough and not clean and crisp.

Then I tried my router on its lowest setting with a round over bit and a sxesp piece and it worked like a charm.

Once I knew it worked, I redid the hand rounded ones as the router still had enogh material to work with and make them even.










Here is another shot showing the texture difference. The surface has a small amount of texture to it, so when rounder over it becomes mirror finish.


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## twang (May 10, 2015)

nice.


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