Re(Calibrator) Phase10 Part2

Now that I have one trial mould, I designated a studio area at home to start experimenting with different materials.

my home studio

Some observations about the materials to be used for moulding and glass casting, will help me narrow down the search.

Polystyrene

Polystyrene or the blue foam is an extremely lightweight; however it is also easily damaged and is very porous, which makes it less useful when high level of detail is required. It is compatible with 3D CNC Router Pacer, easily cut with handheld hacksaw and otherwise manipulated with various tools. The material is easily deformed when heat is applied, it does not have a melting point but burns instead, when the temperature reaches over 200 degrees Celsius. It is completely odourless and relatively cheap to obtain as a raw material. A sufficient amount of detail is achieved for smooth casting with silicon, wax, resin etc. My verdict was that I could not use this directly with glass, but rather create a negative for moulds.

Type B modelling wax (natural)

Type B natural wax is a dense, odourless material with medium softness. It responses instantly to heat source, including the body warmth, making it ideal for hand sculpting and shaping. It melts gradually and feels very “alive” with a distinct character. This particular wax can be melted and reused many times as it carries the mould impressions very accurately and has an almost instant hardening time, when the temperature is cool enough. It is relatively inexpensive,  considering the life span of the material, however the heat factor is prohibiting when it comes to slumping glass or even acrylics.

Lightweight modelling clay

Fimo air-  light professional modelling clay is incredibly lightweight, with 24 hour or less air drying time, depending on the complexity of the piece. It is odourless and easily manipulated by hands or other tools. When wet, it is non-sticky and when dried, it is non-reusable as  one would expect from a standard clay. A piece crafted with fimo air does not have a high temperature tolerance. It is overall a very flexible and consistent material and has from moderate to high impression detailing. The colour is slightly off white. It in unlikely that this can be used for slumping or casting, but it is a great aid for the cast making process.

RTV T30 Silicon rubber

RTV T30 Silicon Rubber is the ideal substance for almost any kind of casting and moulding purposes. It is of a medium weight and viscosity (depends on the type of silicon, the higher the number, the more durable and strong is the outcome) . This particular type is used with a solvent, and can be used with thousands of different materials, since it is non-sticky and has a wonderfully high level of detail impression. 

pouring the silicon into M80 block machined with the router

The hardening time may vary, it can take from 6 hour up to several days, or in some cases, when the liquid has not been mixed well enough, it may produce what I call a “half boiled” egg effect.

silicon cast out of the mould

It is an extremely flexible and durable material, and is resistant to high temperatures. The silicon positive mould was used for vacuum forming and it retained its qualities after the procedure. The mould making process is fairly straightforward and the only inhibitory factor is perhaps the cost; it is too expensive to be simply used as a waste mould.

Standard filler

Tetrion filler is simply one of the standard fillers used in construction. It is relatively heavy and does trap air bubbles after drying. The filler is easy to apply due to its hard cream like quality, and the air drying time is about 6 hours, depending on the depth and the positioning of the material. It proved to be durable to high temperatures. The surface of the dry filler piece is easily cracked and damaged where there is a weak point. It is odourless and has an off white colour. It does not have a sufficient level of details, so perhaps this could be a huge disadvantage for intricate models.  

Plaster

Lafarge plaster (prestia classic)is one of the best known materials in casting and mould making world, perhaps due to its “value for money” factor. It is of moderate weight and density and not very difficult to prepare. The tricky part, however, is to determine the right setting time to work with, as later this will characterise the success of the end piece. The impressions captured by plaster are of high quality, however even after full drying, the piece remains rather  fragile. In order to use this for glass moulds, it will be necessary to mix it with silica.

Fire cement

Sika fire cement  is indeed a very heavy weight alternative and perhaps  the air drying  is not a sufficient  option, a firing is needed, which  makes  this  substance time consuming to a certain extent. It is relatively soft and simple to shape, it is odourless and takes high temperatures very well. It has a warm grey colour and a very smooth, glossy finish  can be achieved. When making a big scale model, the weight can become a worrying issue.

Liquid colour resin

Pebeo colour resin is a precious material to work with  and the outcome is a beautiful surface that is amazingly light weight. The packaging warns that  this  is an extremely dangerous product for the environment, which instantly  makes one think twice before committing to a bigger project, even though it has no  smell or other external indication  of harmfulness.  When  poured, it traps millions of air bubbles, which make the structure weak perhaps plenty of air holes are needed. It responses to high temperatures and softens, might even melt, which suggest a possibility of reusing it. I was considering this as an equivalent to glass, but it is the wrong material perhaps for many reasons, like the cost and the artificial chemical consistency, the fact that it is not as translucent or reflective as glass.

3mm transparent acrylic 

There is a wide variety  of these products available, in all kinds of thicknesses and sizes, and  this along with the relatively  reasonable price,  make perspex so popular. It is lightweight, compared to  glass and has  a much  lower melting point than glass,  in fact it  can be manipulated by a heat gun (about 700 degree Celsius) . However, when heated, it produces unpleasant  fumes  and after cooling, a small number of air  bubbles appear on the surface, perhaps a gradual annealing might solve this. It has a high gloss even surface and is an attractive alternative to glass. This could potentially be used for slumping.

Polyester resin

Clear casting polyester resin is a relatively straightforward material to deal with, comes as a liquid with a hardener. The extremely prohibitive factor is the smell, which is very strong and toxic, if working in badly ventilated area.

Polyester resin drying in a chamber

It is quite a heavy and dense product. It is prone to trapping air bubbles and needs to be poured into a cavity with utmost care and attention.It is not suitable for use with foam materials, as it eats through the foam, which perhaps could be preventing by securely varnishing the surface before pouring the resin.

The dried polyester resin

When drying is complete, the resin looks really beautiful and has nice tactile feel to it, with beautiful reflections and translucency clear and magnificent like that of a glass. Unfortunately the dangerous smell of this resin makes it almost impossible for fabricating a big sculptural piece.

glass wax

Glass wax looks like a mineral and does not react to body heat like the natural wax. However it responds well to a heat gun and melts easily producing paraffin like smell.

melting glass wax with heat gun

On the other hand, when a blow torch is applied, it simply burns, while still melting.

Handheld torch applied to a glass wax

 It its original  form, it is has a frosted looking surface with sharp edges,but after melting it becomes clear and glossy and indeed does look like a glass. Despite this, it is still more of a wax than a glass, therefore it breaks easily and has very low durability in general.

Addition cure 13

 Addition Cure 13 is very similar to Silicon and comes in two parts A and B , which are mixed in equal volumes. It creates translucent human skin colour like soft but durable piece and has a high level of detail.

Addition cure mould for silicon casting

 It works really well with silicon as I was anticipating and is incredibly easy and pleasant to use. But, again, the cost is the major prohibitive factor for architectural applications. 

Polyurethane blocks

Sike produces a wide range of polyurethane blocks, which are the "Holy Grail" for CNC fabrication on 3 2, 3 and 5 axis milling machines and routers. Generally the series start with more lightweight materials like M80, then with higher the number, the surface gets harder and the piece gets more dense harder, for example M1260 is four times the weight and the density of the M80 and is extremely resilient.

The surface f M80 is fragile and easily damaged; it constantly covered in its own dust. The M80 works really well with the 3D router and makes a higher quality finish than polystyrene. Due to its soft structure, it is easily cut with other handheld tools. 
This exercise was targeted to test as many materials as possible and also to investigate into  the relationships of different substances.  Each material with its characteristics allows certain operation while in  the same  time hinders others. It is also interesting to compare those results with the digital materials generated with the help of the computer, of course the latter happens only with a click of a mouse.
Next I will  be experimenting with glass and "refractory" moulds, which are the so called waste moulds for warm glass  (p120 Helga Watkins-Baker, "Kiln Forming Glass", 2010).

Re(Calibrator) Phase10

Two possible methods to produce the desired geometry in glass remained slumping and casting.
Both require kiln or furnace and a pre fabricated shapes or mould to work with.
With the slumping, it is essentially quite simple, all that is required is a shape to slump the glass on it. In this case, the mould is made of either firing clay or plaster with silica mixture or any other suitable fireproof material.

a glass placed on top of the mould before firing

In this case a simple window glass is used and it is cut to size of the sculptural clay mould (page 224, The Complete Book of Creative Glass Art). The piece is then fired in a kiln to an appropriate temperature.

fired glass takes the shape of the mould

Here the edges of the end product are deformed in unpredictable pattern, or at least in this example it is difficult to say where the glass would go, so it is a slightly improvised technique.

Alternatively, we can bend the glass into the mould, which gives us more control over the end geometry. (page 54, Techniques of kiln-formed glass)

Bending glass into mould

Or in some cases, it is beneficial to bend the glass over the mould.

Bending glass over the mould

Most other techniques are more or less similar to those ones.

And another option is casting, which is really an ancient technique that has first been used by Egyptians. The molten solid glass, or frit, or any other crushed glass is heated and as it solidifies, it takes the shape of the mould.

Casting by crushed glass and topping up during firing

There are millions of ways of making a cast glass, in the example above, a crushed glass is filled in the reservoir and more of it is added during the firing. This gives an opportunity for creating unprecedented combinations if desired, but more care must be taken in return. (page 82, Techniques of kiln-formed glass)   

All these techniques have one thing in common, the necessity of having an initial moulds to work with. To be able to manufacturing these moulds, it was time to start  experimenting with real materials and fabricate some full size mould pieces. As a test, I started with a fraction of the geometry, by cropping the piece in 3Ds Max.

Cutting the mould piece in 3Ds Max

I wanted to produce this mould with the help of the three dimensional 3 axis CNC(computer numerical control) router. The router uses a software of its own, called MasterCAM. This program allows to create a G Code for the Pacer 3D router, which is a universal language for CNC programming and is widely used in the industry.  MasterCAM is a complex and sophisticated piece of software that also enables so called cutting simulations to take place, so that the chosen cutter can be tested and monitored. 

Milling simulation in MasterCAM

MasterCAM is a significant software in its direct relation with CNC milling machine. The setup is not extremely complex, but it requires  a thorough understanding of the process, of how the Router works. I started by preparing my tools and adjusting the parameters and running few simulations on screen, to check  the approximate surfaces achieved.

Cutting simulation completed

There are number of different cutting combination and vast amount of cutters, with which I experimented quite a lot.

Library of straight cutter

And each cutter in its turn, has various parameters to be altered and adjusted in accordance to the particular material stock and depth of the cutting.

Cutter Parameters

Apart from choosing the right cutter,it is important to set up the most time effective cutting method for first roughing and then finishing. Same cutting can take much longer if more complex technique is selected, for example in the same simulation for the same cavity a radial cutting  mode is almost 10 times slower than the parallel cutting (the image of the first simulation), although the result is a slightly smoother surface with the radial cutting.

Radial cutting simulation (takes 10 times more time)

Once the setup is complete, the MasterCam produces the G Code, for the Pacer. This code is then  transfered to another software which works directly with  the Router and  in the  image below we can see this  relationship.

Pacer router performing the milling action

On this above image, what we see on the screen is the setup and positioning of the extruded polystyrene (or most commonly referred as blue foam stock on the machine bed. Below is the close up of what is on the computer screen.

The material representation on the cutting bed

Now  that the code has been implemented and the  job has been uploaded, the cutters have been all set up, the router starts cutting. The big bed of the machine is vacuumed, to secure those materials on the bed safely and the extractor  is working  with the cutters.

The milling of the polystyrene

As programmed, the pacer performs the first rouging, afterwards it carefully places down the first cutter and picks up the second, in this case finishing tool, and resumes the work. On the image below, we can see the rough cut area being reworked with a smaller cutter for finishing on M80 Sika block. 

Router performing the finishing with the smaller ball cutter

Consequently, depending on the cutters and cutting techniques, a wide range of outcomes can be achieved.

different cutter and techniques

1. 12mm straight cutter roughing with 6mm staight cutter roughing again with 45 degree angel.
2. 6mm ball cutter  finishing at 90 degree  angel.
3. 6mm straight cutter used for finishing at 0 degree angel.
4. 6mm ball cutter tested at 45 degree angel.

The radial roughing or finishing has not been shown here,since it  was proven to  be unnecessarliy time consuming and perhaps only suitable for rear cases,when the other  methods fail.
After generating these moulds I am ready to go into experimenting  with  various materials.
The 3D router experience is indeed very valuable, in terms of understanding  how the  computer works with  a code,  very similar to how we humans read a book.
When observing  the  machine  work on a delicate piece of geometry  with the smallest of the cutter, I felt a certain admiration and wonder. It is incredible how this big  mechanism of  several tons,works in such a subtle manner, almost like a jeweller. This had a prrofound  effect on me and I found  myself more and more often  drawn to  this machine, experimenting and observing its work.
Until now, the idea  of a code  was an alien concept to me, however,I started studying the G code, very curious to "understand" the machine. The endless pages of numbers and letters started to speak  to me, I found out that when the machine reads G31, it knows that now its time to skip a function, and most importantly I realised that I am the one who told the machine to skip the function in  the first place. In his "The pattern on the stone" William Daniel Hillis, the great American  inventor  describes "I etch a pattern of geometric shapes onto a stone. To the uninitiated, the shapes look mysterious and complex, but I  know that when arranged correctly they will give the stone  a special power, enabling it to respond to incantations in a language no human being has ever spoken." (preface, The Pattern on the stone: The simple ideas that make computers work, 1998). This is a magnificent description of a computer  programming and human-machine "conversation".

Re(Calibrator) Phase9 Part2

After having a session on cold glass  shaping, I went to London Glass Blowing Workshop/Gallery of Peter Layton. http://www.londonglassblowing.co.uk/
There, I had a productive discussion with the glass artists about my project and the techniques that could have been  applied to produce the desired shapes. They kindly  suggested for me to stay in the workshop and find out  how the process flows.

London Glass Blowing workshop/gallery

London Glass Blowing gallery pieces

The glass blowing technique is very traditional and it has not changed much since it has been first discovered in about 50 BC. It has been since then a common practice to use long metal sticks to manipulate the heated glass.

Hot glass dipped in a glass frit

A certain amount of glass is applied on  the end of the metal stick, afterwards, gradually, more  glass powder, broken glass and other variety of matter is added, depending on the desired outcome.

Initial forming of the hot glass

Further shaping with tools

The hot glass is then  shaped and manipulated, by constantly  adding  heat, blowing and forming, while rotating non-stop to avoid the deformation of the piece due to gravity. The water is used throughout for lubrication and cooling.

Heating the glass in the furnace

Once the shape is achieved, a small foot is added, to  put the piece in the kiln, this is removed later on. The heated piece is then put in a kiln for a certain period, depending on the size.This method is called annealing. In the kiln, the object is cooled gradually and this is done to prevent the glass from cracking. When the glass is heated, much stress and  tension is beeing built into  it,  and if it is cooled too quickly,  then the  piece might  break or even  explode.  The heated glass is of course bright red/orange colour and the true colors maybe observed only after it has cooled down.

Glass annealing

After reflecting upon this process, I think  there is a great potential to explore this technique, however I will hesitate for one reason- its very unpredictable nature and its consequent outcome is always an approximation. What interests me more, is the body movement and the gestures while making the glass.

This stimulated to have a look at an existing research in the field of capturing the gestures or human movement and software link.
Of course the graphic tablet which I used to produce the geometry in Z-Brush is an example of this, where the movement of ones hand is registered and further enhanced by the output software.

Touch sensitive graphic tablet

There is a 3 dimensional equivalent of the graphic tablet, it is called interactive Haptic device with 3D virtual brushes/tools. This tool is suppose to recreate the unique touch and feel of the creative process of sculpting, carving, painting etc.

3D modelling with Haptic brush

In essence, the Haptic system was designed to eliminate the need of fabricating a prototype model, it is used with holographic screen (ideally) where the artist can not only see, but also touch the object with the set of tools. It is similar to remote surgery techniques, the same sensation of having something sold in front to work with. When used with a certain material, the stock of the material creates a natural resistance as one would expect from a real material, meaning you can not just push your brush inside it as if it was a hollow weightless mass. This is of course the case with any other 3D modelling software; the virtual 3D objects are weightless and do not show resistance when penetrated with the mouse. Thus with Haptic brush, one can feel as a real artist working with a real material. Even thought this sounds really fascinating, I found the technique to be in its rudimentary stage as I decided to carve my geometry with the use of this system. I got really tired after half an hour, because the clay material I have chosen, behaves as something really sold and it takes a lot of strength to carve into it. My hand simply got tired after trying to push and cut through the material and I did not dare trying something even harder like wood or metal. 
Next I came across Tavs Jorgensen, a Danish born artist and a visiting lecturer at RCA,who is doing an interesting research related to gesture and glass making. Jorgensen came up  with a data glove " the movement data recorded by the data-glove is not used for special effects but imported into a CAD program where it forms the basis for 'solid' shapes that can be realized by a computer controlled milling machine." http://www.autonomatic.org.uk/team/tj/conducting-form.html#/

Data Glove by T. Jorgensen

However, this is not the first concept of the data glove, the idea has been around for few decades, under the names wired glove, power glove, etc.

Data Glove by VPL Research

Above is the data glove by VPL Research designed in 1970s, which conveys the fingers position to the computer via its magnetically coupled 3D tracker mounted on it. (page 303, Mazes for the Mind : Computers and the unexpected ). This concept has taken a very curious turn in the hands of the performing artist Stelarc, who declared that "technology has greatly expanded our senses and made our natural abilities obsolete" (http://www.nextnature.net/2012/03/is-the-human-body-redundant/) 

Stelarc Third Hand

In this image, Stelarc is using an artificial hand attached to his body that is activated by EMG muscle signals. He uses equipment designed for medical purposes, to monitor his physiological factors like brain activity, blood pressure etc, to create a visual performance using gesture and internal control. (http://stelarc.org/?catID=20265)

Drawing with a robotic hand

The hand is quite sophisticated with its pinch release , 270 wrist rotation and a tactile feedback system that creates a sense of touch. It is designed to add to the man's capabilities.

This thinking can enhance our capabilities in everyday tasks if applied skilfully and in good time. Can a third hand be used to support the labour-intensive process of glass blowing? or even touching the hot glass? 

Re(Calibrator) Phase9

In pursue of the right glass technique for the execution of the final design, I paid a visit to various cold glass workshops.

Cold glass workshop

The common cold glass technique is  fairly straight forward; the 3D shape is formed by  layering  flat glass sheets.

Glass sculture by Peter Newsome 

This method is like the manual equivalent of Rapid Prototyping, only instead of powder, the pre-cut glass pieces are placed and glued to form the 3D object. In fact, the material layering technique is quite often employed by architects and planners in their scale models.

London Residential Density model by R. Burdett (LSE)

Each layer  is designed and developed individually. First a decision is made about the thickness of the  glass, since this inevitably  creates  steps,  then each layer is cut, sanded and cleaned with solvent. Afterwards the pieces are glued together with UV glue, sometimes a heat gun is used to get rid of air bubbles. This method  provides a great ability to control the process,which is something that  is perhaps less possible with hot glass. However this technique  is immensely time consuming  and if I decide to go with the cold forming technique, then would look into potentially digitalizing some of  the manual part of the process.
Meanwhile, here  are the basics of this method.

The common way of cutting glass is with  the use of  a glass cutter; the area is lubricated with oils before the cut, to protect  the blade.

"cutting the glass" with a knife

Even though the process is called glass cutting, we dont actually cut the  glass, but scratch and brake it.  (page33, The Glass Artist's Studio Handbook, Cecilia Cohen, 2011).
An automatic glass saws are  also available, there is a constant water lubrication going on with  this cutting process,to protect  the glass from overheating and breaking.

The automatic glass cutter

The water lubrication process applies to a big bench saw too,  when sanding the corners of the piece.

Glass polishing

In glass grinders and drills, normally the heads are made of diamond.

The diamond heads

After these workshops, I was tempted to simulate the cold glass making process for the geometry I am intending to fabricate and to see what it will look like if I was to go with this method.
For this purposes, I First dissected a portion of the geometry and separated it from the rest. 

Selecting a piece of geometry

Afterwards I measured and spaced the sheets of glass that I will be needing for the cutting.

The glass layers created in 3Ds Max

 Then I cut into each layer of glass, assuming that I will be doing the same with the real glass and then reassembled them together.

Layers of glass with different shapes

The results are looking like these.

The projected view of the layered glass object

This is of course not the real representation of the sculpture generated with cold technique, as here I could not achieve the "stepped" effect, but this gives a hint on what this may look like.

Different colour glass with various opacities

Since the geometry that I am trying to achieve is very flowing and organic, this technique seems to contradict to the fluidity of the shape, with its orthodox linearity. I feel that the cold glass layering method, although relatively easy to achieve, perhaps is not right for this particular shape. There are other disadvantages too ; its does not allow for an interior space as the glass is filled through the whole volume of the shape, thus making it extremely heavy and "inhabitable". There is of course a great potential in this technique, but I believe this needs to be combined with another method to achieve more complete and richer structure.