Melting Citadel plastics

[ImperialReaper]

For some time I was wondering what kind of plastic Citadel is using exactly for our warhammer models. I was thinking about melting some of the frames down and fill them into a casting box to create some very unique parts for my army.

But as said, I am unshure which kind of plastics I am dealing with. If it is the wrong type it will probably just melt down to carbon and my ofen will stink for several weeks....

 

So does anyone know the exact kind of plastics we are having in our models?

[DarKHaZZ13]

it burns. its dosn't 'melt' very well.

[CarbonCopy]

GW uses pretty much the same kind of plastic you find in normal plastic model kits -- polystyrene. This kind of plastic can melt, just not very well when exposed to a naked flame.

 

During the molding process, the plastic is not heated directly. Polystyrene is fed into steel molds as tiny pellets, by way of a giant funnel-shaped corkscrew. Tremendous pressure and friction is generated, liquifying the pellets, forcing it to "squirt" into and fill the mold cavity. Sometimes the feader (the corkscrew part) is "preheated" (warmed) to near the plastic's melting temperature, while the molds are sometimes water cooled (they can get VERY hot).

 

This kind of plastic does not lend well to home-brew casting methods as it simply does not get very liquid before it burns. Nor does it stay soft for very long.

 

One method that is used to recycle polystyrene plastic is to use Milliput to make very small open-faced molds of details (like nut/bolt heads, flat skull details and the like -- anything 5mm or smaller in diameter). Once it is cured, it's relatively heat resistant, and takes basic mold release agents very well (vegetable oil and liquid dish soap work well for this). Soften and partially melt the cut end of a piece of sprue and quickly jam it into your small open-faced mold. In a few seconds, you have a "plastic" part you can slice off and glue where you want.

[Tanhausen]

Someone has worked with an extruder! :rolleyes: Very nice explanation of mold injection!

[Hemal]

I'd recommend RTV moulds and resin - plastic is nasty stuff to work with in the home, and I wouldn't suggest trying to make anything using it - I remember teh accidents I used to have with pretty masic vacuum moulding and an electric heater at school - in the home with less safety equipment.....

[Gurth]

The method proposed by ImperialReaper does work, if you want to make only small things and have a mould that the plastic won't stick to. For example, it is sometimes used to make bolt heads for scale models by using a steel die into which a negative of the bolts has been machined (or a hex socket head screw, if you're on the cheap ;)) — but I can't imagine it working well for anything much bigger than, say, the typical size of the skulls moulded into space marine power armour.

[Tanhausen]

Hemal makes a good point: beyond feasibility, safety!

 

The temperatures we're talking about are way to high to handle easily at home... unless you invest in proper equipment, which usually doesn't make sense.

 

Many of us use RTV Silicone and Polyurethane resin to cast our bases and bits. Its cheap (I get 1 Kg of silicone and 2 L of resin for something like 40 Euros) and once you get the hang of it, you can do pretty cool things ;)

[SquigBait]

Another consideration is that when styrene heats up it tends to gas, meaning release fumes, which can be harmful to your health. If you are insistant on doing this at home, get a dedicated toaster oven for this and do it in the garage, do not use the same oven that you use for cooking what you eat.

[Tanhausen]

Actually, I work at a plastic packaging company and when I visited one of our factories (we use huge sheets of polistyrene amongst others) heating doens't release fumes.

 

But I agree, melting is bound to be BAD! I'd strongly dis-advice doing such a thing specially when easy alternatives (resin) are available.

 

Listen to SquigBait, he's a master of the forge <_<

[SquigBait]

Ok, true, heated plastic is fine, such as getting it to temp for vacuum forming, it is when it has become overheated (which is easy to do if you do not have the appropriate equipment) that is gasses.