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Other Stuff => Workbench => Topic started by: whiffwaff on 27 September 2013, 06:30:51 PM

Title: Bendy Plastic
Post by: whiffwaff on 27 September 2013, 06:30:51 PM

I've been asked by a regular customer to explore the possibility of manufacturing some figures for him in that horrible bendy, soft plastic which 1:72 plastic soldiers come in. Not sure why, but he's a bit bonkers which is normally a good enough reason.

I've told him i think it will be mega money, but thought I'd see if anyone knows of cheap - ish casting techniques or companies that can do small runs in this material

Any guidance is appreciated.

Adam

Title: Re: Bendy Plastic
Post by: Cubs on 27 September 2013, 06:35:24 PM

I don't but I do know a good tip for stopping the paint flaking off thin bits like rifles and spears. You give them a brush over with pva between the painting and varnishing stage. It gives them a flexible coat that will help protect the paint.

Carry on.

Title: Re: Bendy Plastic
Post by: Svennn on 27 September 2013, 06:52:37 PM

Polythene is injection moulded so you will need steel/metal moulds which is where the costs rank up.  I have seen hard plastic centrifugally cast but never soft.  Its a good few years since I have been involved with anything like this so others will know better, perhaps there is a resin available with similar properties.  The Chinese factory I used to use was a lot cheaper than the often quoted costs of the likes of Renedra here in the UK but these vary so much I have always taken them with a pinch of salt. There is always the added shipping costs to factor in with Far Eastern manufacture too.

As a side note, I saw one of the most remarkable things ever when visiting the Chinese factory.  Instead of using a computer to pantograph the mould cutting they had guys doing it by hand with dremels.  That's removing a reverse image of the intended product by eye - amazing and bonkers.

Title: Re: Bendy Plastic
Post by: zizi666 on 28 September 2013, 02:08:00 AM

Quote from: Svennn on 27 September 2013, 06:52:37 PM

Polythene is injection moulded so you will need steel/metal moulds which is where the costs rank up.

Not really, where I work we have experimented with aluminium molds. PE can be processed at 140°C (altough we usualy go for 160 to 180° and in rare occassions even 200°C)
The biggest danger lies in the clamping force. Too high and you'll deform your mold (Yes, even a good steel mold gets pressed together a tiny bit from excessive force)
The closing speed is another thing to watch out for. In plastics manufacturing cycles make up the cost. (time is money)
Lousy technicians try to skim tenths of seconds off a cycle by augmenting the closing speeds. In the end they damage the parting lines and flatten the ventings of the mold  :?

The clamping force to be used depends on the projected surface that needs to be clamped (basic physics) so If there aren't too much figures in the mold, it could be kept low.
Nevertheless, keep in mind that the creation of a mold is rather pricey. We got (large) molds costing more than a high end Merc, Beamer or Audi...

Title: Re: Bendy Plastic
Post by: AndrewBeasley on 28 September 2013, 07:45:51 AM

Adam,

Try and get hold of Ken Krout (http://www.blogger.com/profile/15892687506810371341) the owner of Proxie Models - www.proxiemodels.com via http://www.proxiemodels.com/store2/index.php?route=information/contact

Here is his home set up:

http://www.youtube.com/watch?v=7-g-SJ-P9Wg

I know he normally works in hard plastic but he maybe able to help.
 

Title: Re: Bendy Plastic
Post by: Commander Vyper on 28 September 2013, 08:14:46 AM

Why not just use hard plastic and get renedra to do it?

Title: Re: Bendy Plastic
Post by: Cubs on 28 September 2013, 11:16:25 AM

There's a company called Drumlord, just down the road from me.

http://www.drumlord.co.uk/

They're primarily about making protoypes for industry, but their workshops are happy to dabble in just about anything. It's worth a quick phone call or email at the very least.

Title: Re: Bendy Plastic
Post by: whiffwaff on 28 September 2013, 07:48:25 PM

Quote from: Commander Vyper on 28 September 2013, 08:14:46 AM

Why not just use hard plastic and get renedra to do it?

He has a fondness for the figures he grew up with.

I wasnt sure if we'd have to go the route of hard plastic moulding and just use a softer metal or if there was a cheaper alternative.


Cheers for all the help so far guys.