CREATING THE BASE

The base for this sculpture was going to be fairly traditional in style. Firstly I started off by creating a cottle (the white plastic tube form in the images below). In the centre of this cottle was a metal spindle used for attaching plaster blanks to the lathe, making sure that the base of the spindle was covered in clay. Plaster was poured into the cottle to encapsulate the spindle within the plaster,

Once the plaster had set, the cottle and clay were removed revealing the plaster blank on the spindle (below). This was left to dry out for a couple of days to make turning easier.

 Once on the lathe, the blank could be turned. The three images below show the progression of the base.

 

The plaster base was  left on my radiator to dry out fully, then I had to seal the plaster with shellac which is a type of varnish. (see image below)

 

 The plan was to put foundry letters on the plaster with Rupert's name and rank. The problem that I faced was making sure that the letters were central and evenly spaced. The solution I came up with was to draw a circle the size of the base on my work table with a line through the centre, I placed the base within the circle and was able to use the pencil line as guide for marking the plaster. I used Photoshop to produce the text guide, making sure I had a centre line marked, which I could use to line up with the pen mark on the plaster.

Below: Using the print out as a guide I was able to glue on the plastic foundry letters with P.V.A glue, checking the allignment with a steel ruler.

Making the Base Mould Part 3

Above: Once the plaster has set he whole mould is turned around. In this image you can see where I have added an extra piece of clay up the back of the base. This will make an extra thick bit of rubber for me to cut later. Once again I added straws, and the scrim has been removed revealing the bare plaster. 

Below: Circular locks are cut into the plaster surface which will help to lock the two halves of the the jacket together. Clay slip is added to the bare plaster to prevent the next layers sticking. Straws and a retainer wall are also added. 

Below: The plaster steps mentioned previously are repeated to form this half of the mould jacket.

After drawing a circle around the base of the plaster jacket, I opened it up to clean out the clay from both sides (below), this clay is kept to one side so that I can use it to guess-timate the volume of rubber I will need.

The two halves of the plaster jacket are washed, towel dried,  and put back together. Below you can see the pour holes and airs that I made earlier using clay and straws.

The base pattern was unwrapped and given a slight coating of oil, this will act as a release agent for the rubber. it was then realigned  on the base board.

Above: Here I have included an image of half of the plaster jacket replaced, to show how the clay has left a cavity for the rubber. 

Below: The mould jacket is realigned on the board, clamped down, and clay is used to make pour funnels and to seal all of the seams to prevent rubber leaking out.

Base Mould Part 5 Rubber

Once the rubber had cured for at least 24 hours I removed the clay pour cups from the top of the plaster jacket. The excess rubber was cut back to the plaster level on both sides and it was ready to open.

Carefully prising the plaster halves apart revealed the rubber inside. Both halves of the jacket are removed to reveal the bare rubber. I trimmed off the rubber that had risen up the air holes and the flash of rubber from between the two plaster halves.

 

 

 Below: Excess rubber was trimmed from around the keys and once the rubber was taken of the base pattern I set about removing the letters that had become trapped in the rubber surface. The rubber around the letters was also  trimmed to remove any flashes .

Below: Here you can see the extra rubber that was created on the back to act as a location key, this is also the point that I wanted to split the rubber to allow for easier removal of the wax/plaster/casting material that will be in the mould later. It is important to cut this rubber in a zigzag fashion so that it locates in the right position when placed back in the plaster jacket. 

 

Below: The rubber is placed back into the jacket ready to receive the casting material.

 

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Continue Journey 

 

Base Mould 6 Plaster Cast

 

The first thing I needed to do was take a plaster cast from this rubber mould. This 'first pull' cleans the mould and allows me to see if there are any obvious probelms with my mould or how I lay in the casting material.

 

Above: To make sure I got all of the detail I used an old paint brush to paint plaster into all of the letters, without this there is an increased chance of bubbles being trapped in the detail.

Below: Once the plaster had been painted into the details I chose to fill the mould, normally two or three layers, backed up with scrim is used to save on weight and materials.

Below: This first pull revealed that there is still a chance of bubbles being trapped in the lettering as well as on the bottom edge. The following images show the beauty of using flexible rubber.

 

 

 

 

Body Mould 1

(image 1) Firstly I added a funnel to the neck portion of the body (the head had been removed during a previous stage). The next thing to establish was the seam line, as with any mould this is usually the widest point or points. I began by pushing metal shim into the plasticine at regular points around the figure.

 

Images 2,3,4 and 5: The shim formed anchor points for me to cellotape the sheets of shim to, this was continued around the edges of the figure getting as close to the plasticine without disrupting the detail. The figure was then loosely covered with cling film (Image 5).

 

Above: In the first 5 images above you can see where I have layed a 6mm thickness of clay around the figure. Then a blanket of clay was layed over the the whole figure smoothing out the surface as it progressed. Triangular keys were added around the perimeter (to hold the rubber in the jacket later) along with a cone of clay (to pour the rubber in) and a natch (to help hold the rubber too). This is all covered in plaster backed up with scrim for strength, exposing the top of the clay cone.

Above:In the next 6 images you can see where the mould was rotated to reveal the back. The shim was removed along with the aluminium support (the plaster jacket holds up the figure now). A protective layer of cling film was added again, circular keys were cut into the surface of the plaster and the clay steps were repeated for this second side.

Body Mould part 2

Once the jacket is complete, the mould is opened.

The clay is removed from the side that does not contain the figure and put to one side. (this can be used later to work out the rubber needed to fill the cavity).

The seam edge is worked up to the figure to make a water tight seal, smoothed off and location points can be pushed into the clay around the figure. (see below)

mould..continued

 The plaster jacket half that was removed initially, is cleaned and holes are drilled at the high points (when the right way up) to act as air holes for the rubber. The plaster is coated with a couple of layers of wax release and allowed to dry. This prevents the rubber from sticking to the plaster.

The open ends are worked so that they are water tight and to give the best results later.

The mould is strapped together and boards are placed at both ends and clipped in place. This is the perfect opportunity to prepare any other moulds that need rubber. In this case I put clay walls and wax release on the head, hands and gun moulds.