Plastic Moulding

[qwerty123]

Hey,

 

I'm wondering if it is possible to safely mould plastics. I know the problems are that it gives of toxic fumes and often chards before it melts. But companies do it using some sort of powder ? Then they simply melt it and mould it and allow it to chill. Does anyone know what the plastic it is that I can use ? It needs to be strong when it solidifies . Also I need a material I can mould it in which can easily be shaped etc ? Can anyone help me ?

 

Thanks a lot !

[akcapr]

i saw a discovery channel show about plastic moulding

[YT2095]

LDPP or LDPE are idea thermo setting plastics for experimenting with, a low MP and no toxic fumes if you accidently overheat it.

of course you`ll need some way to deliver this liquid, it`s usualy done by injection moulding at high pressure.

there were many plastic that we used to recycle by sticking them into a Huge shredder and then mixing this material with virgin plastic and re used.

[qwerty123]

thanks for the advice i will look into them 2. What meterial could i use for the moulds. It needs to be something that can withstand the heats from the melted plastics but it also needs to be easy to craft. Any1 know of nefing ?

 

Cheers

[YT2095]

how about plaster casting, make a model from wood, put a light coat of oil on it, then half fill a pot with plaster then sink your wooden model in it half way.

allow the plaster to set, and then coat the top surface of the plaster around the model with petroleum jelly, then pour on the remaining plaster enough to totaly cover the model.

allow it to set, and with a bit of luck it should all come appart quite nicely leaving you your negative.

drill an input hole to pour the plastic and have a vent for displaced air to escape.

put the 2 halves together with elastic bands and you`re all set

 

if you use the right plaster, you can even mold in lead!

[qwerty123]

can you use old mouse cases and melt them .I got plenty of old mice. These mice were probably made using injection moulding so could I melt these down? I know you probably will not know unless you knew what material it was .

 

Also can you get colorants for the melted plastics ? just so i can make it a nicer colour ?

 

Cheers

 

P.S I only want to melt the case of the old mice

[YT2095]

mouse cases are usualy ABS. ABS Can be reused but the material has to be 100% dry and the melting temp is critical too.

it`s Not the ideal material to use.

[gcol]

Am I misunderstanding something here?

 

As far as I know, there are no household ware plastics that can be liquefied by heat without destroying them. The process is to heat them just enough, below degradation temperature, until they are just soft enough to be injected into a mould using high pressure.

 

The only one I have come accross that is liquid at room temp is called, I think, something like 'plastisol', used in the printing trade and for cold dip coating/moulding (similar to making candles). This material actually hardens/cures when heat is applied.

 

I have also heard of a "hobby" resin used for encapsulating flowers, insects, whatever for things like pendant jewellery.

 

I speak from both distant memory and recent practical experience in dealing with the plastic moulding industry.

 

If I am wrong, someone please put me right.

[YT2095]

LDPE and LDPP can be "liquified" (it`s still honey like viscosity though) and re-set without problems

 

think the plastic rings that hold the beer cans together )

[qwerty123]

It would be quite simple a air tight container with a whole to put in the solid plastic then when its air tight using pressure on the lid compress it through a whole at the bottom into the mould. With some sort of corkscrew shape mixer in the middle. Should be easy enough I only want to do this as a tester and if all goes well i may do it more often .

 

Cheers

 

Can you get colorants for the plastic to add once its melted ?

[YT2095]

coolants, yes, Water

 

what i Would say though is that make sure the plastic heats Evenly and slowly, avoid local heating at all costs!

 

a double boiler may be helpful with this.

[qwerty123]

http://www.goodfellow.com/scripts/web.wl?MGWLPN=MNT&PROG=SEARTOW&LAN=A&HEAD=ET31&SPAGE=ET31&FORM=63

 

Look at that link LDPE looks very expensive.

[qwerty123]

is there colorants ? not coolants

 

Cheers

[YT2095]

there are colorants (sorry about misreading), we had a whole set of draws full of them, sadly I had no idea what they were, there was only Numbers on them and that had to match the specific job we were doing, I don`t think I can help there too much.

 

I do Rem that Titanium Dioxide powder was brought in by the sackfull to make the White color though.

 

surely you can re-cycle the LDP E/P ?

it`s quite safe to work with (other than the heat) and quite a few things are made from it

[qwerty123]

no problem I always miss read stuff ! lol. I will take a look at what’s about on the internet I am sure I will be able to find something. If you come across anything please let me know

 

Thanks for your help

[qwerty123]

Hey,

 

I have been looking around for colorant pigments for plastics . I really cant find anything lol ! I have found loads to do with yellows and reds. But really i want black ! Does anyone know anywere !?

 

Thanks I might start a new thread to look into this