Day 5 - Dollmaking basics - Preparing for casting

Last time I did a batch of casting was late summer last year, and it was hot, which made the job of working with moulds and casting slip marginally more pleasant.  There's not much pleasure to be gleaned from handling cold plaster moulds, and even colder porcelain slip during the winter months.

But first, because the tub of slip has been sitting in my casting cupboard, undisturbed for several months, I had to go through the tedious process of conditioning and resurrecting it.  Stored slip settles in its container, going thick and gungy at the bottom, with a layer of watery liquid on top.  It is unusable in this state, so it needs to be thoroughly sieved, several times, and stirred to within an inch of its life.

As my slip pot was only about a quarter full, I also decided to prepare a new batch to add to it, figuring that it was as well to be hung for a sheep as a lamb.

Preparing slip is a messy business.  

As previously mentioned, porcelain slip is incredibly slippy and gets absolutely everywhere.  It's cold and slimy and intractable and it takes a long time to make it workable.

The first step is to cover every surface with newspaper, including the floor.  A little slip goes a very l-o-n-g way. 

These days, it is supplied in boxes, which hold a heavy duty polythene bag containing 3 litres of slip.

Back in the good old days, slip was always supplied in large, wide-necked plastic tubs, which made the task of pouring and stirring so much easier, but progress has dictated that poly bags are the way forward so nowadays this is what you get......

Just as it would do if it were stored in a tub, the slip settles in the bag, going thick at the bottom and watery towards the top.  However, the bag does have one advantage over a tub as it can be kneaded and pummelled to mix the slip.  This takes some time and is roughly equivalent to a 1 hour upper body workout.  It's much harder work than kneading bread dough but is probably excellent for conditioning bingo wings and flabby bits.

When the bag has been suitably pummelled, its time for the first sieving......

Despite the thorough in-bag pummelling, there are still lots of lumps and gloopy bits that must be removed in order to produce a smooth, creamy slip.

Who would have thought that three and a quarter litres of porcelain slip would take up so much bowl space?  The old and new slip need to be very thoroughly mixed together as there is likely to be some difference in colour between the two different batches.  So there needs to be about an hour of sieving and mixing, mixing and sieving until every tiny lump is gone and the slip is one homogeneous colour.  It can then be transferred back into the plastic tub and marked with the date. 

Voila!

Tomorrow... the next stage, casting