How it's made....bisque firing

The next stage in the making of a microdoll is the most critical.... the bisque firing, during which the soft-fired, relatively fragile castings are vitrified into porcelain.


The vitrification process literally melts the molecules in the greenware so that they fuse together, forming a strong, impermeable material with the properties of porcelain.  

During this high-temperature firing, each piece shrinks by up to 10% so careful loading of the kiln is very important.  I  first place a thin layer of firing sand on each shelf.  This serves two purposes.  Firstly the pieces can be slightly embedded in the sand which stops them rolling around, and secondly, as the pieces shrink during firing, they may 'grab' onto the shelf. The sand acts like millions of tiny ball bearings, moving under the pieces to prevent them sticking.
Every single piece must be placed carefully on the sand, not touching its neighbours.

This can take some time!


When the kiln is fully loaded, I set the programmer for a high-temperature porcelain firing. The programme varies according to how full the kiln is, the type of porcelain being fired (different flesh tones require slightly different firing schedules), and the age of the kiln elements.  Over time the elements deteriorate and the firing time gradually lengthens.  Eventually they will struggle to reach the top temperature, taking longer and longer to achieve a full bisque firing.  At that point it's time to replace them.

I replaced the elements on my kiln just a few months ago, and this firing is only the second full bisque firing since then so I have had to adjust the schedule to take into account the speedier firing time.

As it reaches the top temperature (1200-1215 degrees Celsius) the firing chamber glows white hot.  It's possible to see this through the gap between lid and kiln chamber.

I keep a close eye on things as the kiln nears the end of the firing, checking every 15 minutes to see the final few degrees temperature rise then the soak time, where the top temperature is maintained for a set period to fully mature the porcelain.


This last bisque firing took 6 hours.  Before I changed the elements a bisque firing was lasting 10-12 hours.  Once the firing is complete the programmer displays 'END' and switches off.  The temperature falls slowly over many hours.  I usually leave the kiln for at least 12 hours, by which time the internal temperature should be low enough to open the lid and check the firing.  If the lid is opened too soon, cold air rushes in to come in contact with the hot porcelain causing thermal shock.  This has never happened to me (thank goodness) but I understand that it is quite spectacular, as the porcelain pieces shatter, scattering like shrapnel, and possibly causing serious injuries.  One of the main advantages of my kiln is that even when the kiln is off, the internal temperature shows on the controller, so I always know exactly how hot it is.

However that is not always the case.


An underfire happens when the top temperature required to vitrify and mature the porcelain hasn't been reached.  As a result the porcelain has a chalky look and feels rough to the touch.
This is disappointing but not disastrous, as it can be re-fired to maturity.


An overfire however, is irrevocably catastrophic.  The porcelain will look shiny, often with tiny bubbles all over the surface.  Any flesh tones will have fired out to leave a ghostly look.
In the worst cases, the castings will completely collapse.


In order to avoid both of the above scenarios I keep a careful record of each firing, adjusting and fine-tuning subsequent firings as necessary.


And so to the next stage...... china painting

 

How it's made.....soft cleaning

The third stage in miniature porcelain dollmaking is the most tedious, boring, monotonous task in the entire process.  

Soft-cleaning.

This follows on from soft-firing, and although it is my least favourite task, it is one of the most important, as it ensures a smooth surface, removing seamlines and any other marks and blemishes left over from the casting stage.

Here you can easily see the seamlines on a soft-fired casting.

I always approach soft cleaning sessions with a mixture of resignation and dread.  Although the soft firing strengthens the greenware castings, they are still very delicate and easily broken so must be handled very carefully to avoid damage.  As a result, after half an hour or so, I have to make a conscious effort to relax my shoulders down from my ears.  Then there's having to sit with my hands in water for hours at a stretch.  I start off with it as hot as I can stand it, but it soon cools and I don't notice until my fingers start to turn blue.

The upside of soft-cleaning is......... well to be honest I'm struggling to think of any, except perhaps that I get to put my brain in neutral and give myself over to Radio 4 for the whole day.

Before I start I assemble everything I need - towel, double basin, used scalpel blade, fine cleaning pads, natural sponge, china glaze and extra fine paintbrush.  I also use a magnifying lamp to help with cleaning the tiny faces.

Firstly the soft-fired castings are soaked in water, which must be no warmer than lukewarm. If they are immersed in water which is any hotter, air which may be trapped in cavities inside the bodies will expand, and the piece will explode.  This happens with quite a  startling, loud POP when you least expect it!  I use a double basin so I can have my hands in warm water for the cleaning, while the castings soak in cold water.

Soaking the castings in lukewarm water. 
Most air bubbles escape though pouring or stringing holes.

After soaking for 10 minutes or so, I can begin the cleaning process, as all of the castings will have fully absorbed the maximum amount of water.  Prominent seam lines must be fettled with a scalpel blade.  I prefer to use a blade with has been used to trim castings and which as a consequence will not be too sharp.  New blades have a tendency to cut into the castings.

Carefully removing seam lines with a bluntish blade

 
Then using a special very fine abrasive pad, the remainder of the seamlines are smoothed off, along with any blemishes on the surface of the greenware.  

 Smoothing lines and blemishes with abrasive pad

The 'dust' from the greenware is held in the water on the surface of the casting in the form of a fine paste, which acts like micro scouring powder to gently remove lines and marks.  I then add my initials to the back of the doll using the point of a scalpel.   

Incising my maker's mark

Each soft-cleaned casting is set aside on a towel to dry slightly, until the sheen of water has evaporated from the surface, making it easier to check the faces.  Any blemishes on the faces are removed by rubbing my thumb over the area. The ridges which make up my fingerprints are  just abrasive enough to smooth the surface without obliterating tiny details such as noses and lips.  Faces will be checked several times to ensure they are as perfect as possible.

I prefer to use a special underglaze for the whites of the eyes, which is added at this stage, when the castings are not too wet and not too dry.  Being left handed, the left eye (as I'm looking at the doll) is easy peasy, but painting in the right eye is not.  So  have to turn the doll at right angles to achieve an almond-shaped eye.  Obviously both eye whites must be the same size and shape, which is where the magnifying light comes in useful.  Even so, it sometimes takes several attempts..... if I make a mistake I wash off the glaze with a natural sponge, let the casting dry out slightly, and try again.

Glazing the eye whites

Bear in mind too, that the biggest doll heads are roughly the size of a pea, while the smallest are only marginally bigger than a peppercorn.

Mad or what?


The soft-cleaning process also applies to the tiny toy animals and nursery rhyme toys which I make in porcelain.  The most difficult of these are the little Humpty Dumpty toys, which have spindly little legs attached to the egg-shaped head/body, which can ping off unexpectedly despite the very gentlest cleaning.  Out of every 10 Humptys, perhaps only 2 will emerge unscathed from the soft-cleaning stage.

But it doesn't end there.

No by no nonny no.

For every little toy doll, there are two arms and two legs, which must also be cleaned to remove seam lines and blemishes.  That's 4 tiny limbs for every one of these.......

There's 92 different dolls, so that's 368 individual limbs to carefully clean.  From dainty ballerina arms and pointed toe legs and tiny 1" babies, to a brand new range of marionettes, with specially modified arms and legs.

It can take up to a week to soft-clean enough castings to fill my kiln by which time I have invariably lost the will to live and make a solemn vow NEVER to soft-clean EVER again.

How it's made..... soft firing

When I've cast enough tiny dolls and toys to (hopefully) fill the kiln, or lost the will to live, whichever comes sooner, they are set aside to air-dry completely. 

The dry greenware is very fragile and can crumble to dust so must be handled very carefully.  However, the casting process leaves seam lines where the liquid porcelain slip seeps slightly into the gap between the two halves of the plaster mould.  These seam lines must be removed, along with any blemishes on the surface of the casting.

It is possible to do this with a small piece of abrasive fabric (such as nylon net) but dry cleaning produces lots of dust, which contains silica, and is harmful to breathe in over a long period of time.  Also, as the greenware is so very fragile, it is extremely difficult to avoid breakages, especially when cleaning tiny pieces.

Years ago, I used to dry clean my castings, wearing a special mask to avoid breathing in the dust.  However the fine dust gets EVERYWHERE, so inevitably it is impossible to avoid inhaling it as it permeates clothing, fabrics, rugs etc.

Eventually, some bright spark discovered that if the greenware castings were fired to a very low temperature (approx 650 degrees, which is still much hotter than a domestic oven) any moisture remaining in the porcelain would be completely driven out, resulting in a casting which could be immersed in water without dissolving, but still be soft enough to be able to be cleaned.  And so the dust-free soft-cleaning procedure was born.

Soft firing does not vitrify the castings, so they can be loaded into the kiln with less precision than for a bisque firing.  They won't fuse together so the pieces can touch.  The castings will also become lighter and stronger, although they are still easy to break so require careful handling.

Here a selection of castings are placed on the bottom shelf in the kiln, with the shelf supports in place to support the second shelf.

After the soft-firing is complete, and the kiln has cooled down, the castings are removed and stored in boxes.   Soft-fired castings can be stored indefinitely with less possibility of damage than unfired greenware.  


They are now ready for the next stage - soft-cleaning

How it's made.....casting

I've decided that I might as well make a virtue of necessity and give you an inside look at how our microdolls are made.

The process is long and takes several weeks but it starts off with casting.  I'm currently casting tiny ballerina dolls and new marionettes, but a complete casting batch, completed over several weeks, will also contain toy porcelain animals, marotte heads, Punch & Judy puppets, nursery rhyme and fairy tale characters.... all the toys we create in porcelain.

All of our tiny porcelain dolls start out as a puddle of slip.  Porcelain slip for miniature dollmaking is specially formulated and available in a range of flesh tones as well as white and other colours, which we use for different toys.

It needs have just the right texture and the consistency of single cream.  It has to be stirred and sieved to remove any lumps before casting, whilst taking care not to introduce air bubbles which can leave tiny pin holes on the surface of faces and bodies.

Before I start, I prepare the work area, spreading newspaper to soak up any spills.  Because tiny doll moulds 'set up' so quickly, it is only possible to cast a few at a time.  From pouring the slip to releasing the mould takes around 10-15 minutes, depending on the air temperature, humidity, how dry the moulds are etc, so if I try to do too many at once, I will run out of time to get them all open in time.  For this reason I usually cast up to 5 at a time.

First, I always check inside each mould and remove any dust or dried porcelain slip with a soft brush.  The inside of the moulds are easily damaged and any marks will transfer to the casting.  The mould below is for one of our most popular toy dolls and it's possible to see the head/torso, arms and legs outlined in the plaster.

Once checked, the moulds are tightly re-banded to avoid any seepage of the liquid slip between the seams.

The pour holes are tiny, so the only way to ensure that the porcelain slip gets all the the way inside the mould without drying out halfway down, is to use a syringe.  I insert the tip of the syringe inside the mould and carefully fill each cavity

Just before I begin filling the first mould, I set a timer for the amount of time I judge will be required for the casting to set up.  This varies according to several factors and is where 20 years of experience comes into its own!  When all the moulds are poured they are left undisturbed until the timer goes off.  During this time, water is absorbed from the slip by the porous plaster and the slip changes from liquid to solid becoming leather-hard greenware.


Now I have to move quickly.  If I leave the greenware in the moulds for even a few minutes too long they will dry out and crumble when they're handled.  The castings must be just dry enough to easily release from the mould, but not too dry that they're unworkable.

Again, years of experience will tell me whether the mould will release and open easily.  Trying to open the mould too early will result in the casting ripping apart.  Perfect greenware will release smoothly with every piece intact.


Once open, I gently remove the castings, one at a time, starting with the smallest, most delicate pieces first, usually the arms. Using a scalpel blade, I trim off the excess formed by the pour holes, and make stringing holes with another of my favourite tools.  As soon as the greenware leaves the damp mould, both the air and the heat of my hands accelerate the drying process so I have to work quickly, while still handling the soft, malleable pieces very carefully.  If the greenware is compressed, distorted or otherwise damaged at this stage it will be ruined.  Porcelain has a 'memory' and will revert to its damaged state even when attempts are made to restore the original shape. 

 If I have misjudged the time, or there is any delay in opening the mould, this is the point at which the tops of tiny arms will break off, or cracks appear in bodies so this part of the proceedings is always a little tense.  If the phone or doorbell rings I can't abandon my task, which is why I always give an all-points warning to everyone in the house that I'm doing a casting session and can't be disturbed UNDER ANY CIRCUMSTANCES, short of a life and death situation.

Today's session involved making stringing holes in the limbs and the bodies but other dolls might require the excision of tiny eye sockets, provision for articulated heads or other modifications to the basic structure.  The prepared pieces are then placed on a board to air dry thoroughly.  

Each small batch of casting, comprising 5 dolls, takes at least 45 minutes to complete, from pouring to setting on the board to dry. Needless to say, it takes quite a lot of such tiny pieces to fill all three shelves of my kiln, so the casting process will be repeated two or three times a day, over several weeks, before the greenware can progress to the next stage...... soft firing.