The chocolate forming device featured in this instructable is used to create strings of chocolate without the need for an external or internal heat source.
Now I here yourself thinking is such a thing possible? Well yes it is possible to shape normal milk chocolate without the need for heat. All you do need is a high pressured squeezing system.
Whats more you don't just need to stick to boring profiles like a circle, you can have the filament come out any number of different shapes, but generally the simpler the better.

When the string is first extruded it is malleable and thus workable, you can use it to do whatever your imagination gives you but if you have trouble, I have included a uses page at the end of the instructable. After a while it turns a bit brittle as though tempered which makes it really tasty.

Step 1: Choc Chamber

The chocolate chamber is where all the chocolate is stored and compressed in.
For my chamber I used a Ø60mm aluminium tube with wall thickness 10mm. the length I decided on is 150mm but could be anything from 50mm up.(Couldn't be much shorter because piston is large). I bought this peice of aluminium from ebay seller forward metals (http://www.ebay.co.uk/itm/Aluminium-Tube-60mm-Diam-x-10mm-Wall-x-250mm-Long?item=150337213831&cmd=ViewItem&_trksid=p5197.m7&_trkparms=algo%3DLVI%26itu%3DUCI%26otn%3D1%26po%3DLVI%26ps%3D63%26clkid%3D8273219770097453398)
As you can imagine, (not very clear in picture), this is quite a chunky piece of aluminium. It has to be so chunky so that holes can be drilled in the ends to hold the mounts and extrusion plates. Both sets of holes consist of 4 drilled and tapped M6 holes.
drilling these holes straight proved to be quite tricky for me, as the milling machine I had access too was a bit too small with the vise already on it which is why in the photo there are two vises on the bed(the old one is smaller).
Whenever doing low volume tapping operations after drilling on the milling machine, I start the thread off in the machine as to getit straight from the beggining. I think the photos show this operation clearly but do leave a comment if you have trouble understanding it.
AspireBlack3 years ago
Heads up, aluminum should never be used with food unless it has been anodized(electrically oxidized to form a hard outer layer). If not, the Al can be reactive with foods and toxic. machining certainly scraps away any existing oxidation. Always make food tools out of 304 or 316 stainless steel! I hope you read this ASAP. Well written DIY, but remake with stainless!
MR.Geo (author)  AspireBlack3 years ago
A bit sceptical about this comment (what about all those aluminium pots and pans used with heat thus increasing rate of reaction). Please could you post a link to any reputable sources that share this view or maybe a research paper.
Hysteria... While aluminum accumulates in the body over time and can become toxic, there are rules it must follow to do so. After machining, aluminum immediately forms an oxide layer, although not as hard as 'hard' anodizing (there are different types/methods of anodizing that provide various levels of protection). Aluminum is used in antacids, antiperspirants, and..... get this..... ALUMINUM FOIL!
Aluminum is reactive (as is copper, and iron), meaning it will form ions or salts in the presence of acidic or alkaline foods. These forms of aluminum are bad but toxic exposures are usually found in the workplace/industrial settings - not in the kitchen.
Chocolate is only slightly acidic so there may be very small amounts of aluminum absorbed but you are probably in more danger of contracting food poisoning from a dirty stainless steel container than toxic exposure to aluminum from kitchen utensils.
MR.Geo (author)  Old Nubbins3 years ago
Thank you for your input in this matter.
phenoptix3 years ago
Great instructable! I've been wanting to do this since I saw chocolate extruded on a trip to Trinity College Cambridge. I've not seen it since but recently tracked down the papers published by that group.

My only thoughts to improve the instructable would be some nice shots of you bending the extruded chocolate, perhaps a plait?

I see also you're from Beds, whereabouts? I grew up in Dunstable...
MR.Geo (author)  phenoptix3 years ago
I saw that extruder during a science week at school about 4 years ago but had completly forgotten the details except that it had a bottle jack in it somewhere.
Near Shefford
I searched for research materials to do with this but came up empty, could you post a link to where you found the documents please?
These were the guys I saw showing flexible chocolate: http://www.ceb.cam.ac.uk/pages/flexible-chocolate.html

I know a little of Shefford as I used to go to Henlow with cadets.

A paper by them explaining the phenomenon a little is available here
soul_eater3 years ago
Very Nice, i make somethig like that some years ago but i used a pneumatic cilincer and i aded a second cilinder around the one that have the chocolate with a resistance boiling water to help the chocolete to melt a little