Wednesday, 18 January 2017

Day 18 - Bisque firing

I'm currently still mired in soft-cleaning hell, but in a week's time, when it's all done and dusted, it will be time for the next stage - bisque firing.

This is the most critical part of the dollmaking process, 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.

This can take some time!  Several hours is needed to place each tiny piece in place on the shelves as every single piece must be placed carefully on the sand, not touching its neighbours.

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 six months ago, and this firing will be 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.


My last few bisque firings 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.

As I said, I'm hoping that by next week I will be through the tunnel of soft-cleaning and able to bisque fire my latest batch of castings.

After that, it will be time for the next stage...... china painting.

Tuesday, 17 January 2017

Day 17 - My all-time favourite shop!

By chance, the following BBC News article popped up in my newsfeed this morning.....



My Shop: Kristin Baybars' toy shop in London
17 January 2017 Last updated at 00:19 GMT
Kristin Baybars has been making and selling toys for the past four decades from her self-named shop in Gospel Oak, London.
Money has never been her motive but with more people shopping online, times are getting harder - and a housing development next door is adding to her woes.
Video journalist Dougal Shaw went to visit her to find out what she makes of modern toys.

To view the short video, click HERE!

I have been to Kristin's wonderful shop several times and it never fails to amaze.  Many shops are labelled Alladin's caves, but hers takes it to the next level and beyond.

Tucked away in an unprepossessing part of Gospel Oak, in north west London, at first glance it may look closed for business.  This isn't a place to which you can just bowl up and expect to find open.  

No. You have to make an appointment.  In advance. 

But, trust me, if you love doll's houses and miniatures you'll be very, VERY glad you did.

It. Is. AMAZING! 

I still remember the very first miniature I ever bought there... over 30 years ago.  It was a little dressed doll in a hand-painted box.  Perfect and exquisite.

Kristin herself is a truly wonderful eccentric, and what she doesn't know about the doll's house hobby isn't worth knowing.  

It is so sad to hear that this wonderful shop may have to close, due to the rise of online shopping and the threat of development next door.

I would strongly urge anyone who has the chance, to visit this unique shop, which has a special place in doll's house history.

It can be found at 7 Mansfield Road, London NW3 2JD.... but don't forget to ring for to make an appointment first!  Tel 020 7267 0934


Monday, 16 January 2017

Day 16 - January Giveaway Competition

So.

Just over halfway through my 30 day blog challenge and it's time for the next part of my giveaway competition.

Here are two photos of my day nursery room box.  The top one is the original, the bottom one has a few things changed, removed or added.

All you have to do is post the number of differences.  I won't publish the comments so that everyone has a fair chance.

Simple!

If you click on the photos they will enlarge....





Good luck! 😉

Sunday, 15 January 2017

Day 15 - Soft cleaning....

Although I'm probably still a week or so away from being able to carry out a soft-firing, I'm mentally girding my loins for the next part of my dollmaking journey.

If you thought casting was bad, think again.  The third stage in miniature porcelain dollmaking is the most tedious, boring, monotonous, frustrating 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.......


As I'm still at the casting stage, this is photo of a batch of soft-cleaned dolls from last year. There are 92 different dolls, so that's 368 individual limbs to carefully clean.  From dainty ballerina arms and pointed toe legs and tiny 1" babies.

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. 

*sigh*

Saturday, 14 January 2017

Day 14 - My Frankendolls experiment.....

A few days ago I mentioned that I like to mix and match heads on bodies in a Dr. Frankenstein styley.  One of the comments that day was from Megan Wallace *waves hello* who provided a link to another blog, and a post on Frankendolls.

I'd been unaware of the controversy surrounding so-called Frankendolls, but I can absolutely see why, in the antique doll world, they are a complete no-no.

However, as I'm not trying to pass mine off as anything other than artistic craft creations I'm sure I'll escape the curse of Frankendolls.

Anyways... one of the photos in that post got me thinking....



What if I transplanted some of my toy animal heads onto doll bodies?


Sorry it's not a great photo... the light was fading, but you get the idea.  In the top row, from right to left, rabbit, cat, hare, mouse, mouse, duck, lamb, lamb.
Second row... bear, rabbit, hare, car, bear, bear, goose.

Each animal head has been grafted onto the relevant size of doll body.  I also cast matching arms and legs for each hybrid.

I'm thinking that I can dress them in suitable clothing and use them as toys.  I remember when I was a child, I had a doll that had a rabbit's head, and was dressed in clothes so I think it might work.

Can't wait to get the rest of this casting batch finished so that I can crack on with soft firing them.  

Mwahahahaha!

This channelling of my inner Dr. Frankenstein is strangely satisfying....

Friday, 13 January 2017

Day 13 - 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 will be set aside to air-dry completely for several days.  

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 or pinholes 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 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 safely 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. 😩

Thursday, 12 January 2017

Day 12 - Now for the science....

I use many different tools and pieces of equipment, but the one which is completely indispensable, and without which I simply couldn't carry on the business, is my electric kiln.  In simple terms, a kiln is a furnace, or oven for burning, baking or drying something, or more commonly for firing pottery.



This is the largest top-loading kiln I could find which would operate via a 13 amp standard UK electric plug and still reach a top temperature of 1260 degrees Celsius, the temperature required to vitrify porcelain.   The vitrification process uses heat to convert the chalky, fragile greenware into a glass-like substance - bisque porcelain. 
Although it isn't strictly speaking 'glass', if porcelain is held up to light, it should appear translucent.  



Inside you can see the thick, insulating kiln bricks, which help keep all the heat inside, and running in channels around the inside edge, the spiral, metal kiln elements, which glow white hot at their top temperature.  Within this firing chamber I can place up to four shelves, one on top of the other, separated by shelf props, in order to maximise the firing capacity.

This is only my second kiln in almost 30 years.   The first, which I had for 15 years, was a Cromartie Hobbytech 40, slightly smaller and a manual kiln.  When I decided that I wanted to upgrade to a computer controlled kiln, I was able to sell my old one for the same price as I bought it for. 

Cromartie kilns are THAT good.

Sadly, Cromartie, a UK firm based in the heart of the potteries district of Stoke-on-Trent are no longer making kilns, but due to their excellent build quality, existing Cromartie kilns will continue in use for many years to come.

My firing schedules consists of three different stages - soft firing, bisque firing and china paint firing, each of which has different ramp times, temperatures, soak times etc, which I have programmed into the computer controller.  Once it's set to fire, the computer takes over and regulates the whole process, which takes the guesswork out of things.  

However, skill and experience are required in order to get perfect firing results and I have  worked out my own set of firing programmes, gleaned from hundreds of firings over the past quarter of a century.  These programmes have to be adjusted according to the type of porcelain slip I'm using, the size of the castings and age of the kiln elements, among several other factors.

Having only recently replaced the kiln elements, I've been able to knock  several hours off a full bisque firing, as the new elements can reach the required top temperature much more quickly.  However this means that I have to reduce the soak times and adjust the top temperature to suit the tiny pieces I'm firing, otherwise I risk a catastrophic overfire.

It takes a LOT of dolls and toys to fill my kiln, which is why I have to spend several weeks casting so that I can hopefully fill at least three shelves with tiny doll parts.

Next up.... soft firing and cleaning.