Saturday, 7 May 2011

Ultra Chic..........

No, I'm not talking about upping my sartorial game (currently wearing jeans, red vest top and rather dashing red and blue Hawaiian-style print shirt so admittedly I could legitimately be charged with crimes against fashion.....)

Rather, the Ultra Chic to which I refer is the casting slip successor to Seeley's, who are no longer trading.  I'm down to my last half gallon of the old Seeley's slip, which I've been using ever since I started working with porcelain over a quarter of a century ago.  I knew it inside out..... just how long to leave it in the moulds to set up, how to thin it to just the right consistency, exactly what firing schedule to use to guarantee the best results.

However, now that it's no longer available I've been forced to change to the new slip on the block.  My first two gallons arrived yesterday, and it's sitting on my casting bench awaiting its first use as soon as I'm done with the accounts.  

There's nothing like a good incentive to make the task in hand more palatable.

I'm also awaiting a new set of kiln elements, so once they arrive and I can replace the old ones, I can set about doing a test of the new slip.

Apparently, Ultra Chic is light years ahead of Seeley's slip.   According to the accompanying information sheet it de-airs very quickly, which means that any tiny air bubbles left by stirring the slip prior to use, will quickly rise to the surface and dissipate.  This is important as air bubbles left in slip can cause tiny pin holes in the casting, which invariably occur at the end of noses, or over an eye, where they are most visible, rendering the affected pieces unusable.

Apparently it does not separate, so mixing is always easy.  This is an advantage over Seeley's which if left for a period of time would separate so that the solids would fall to the bottom of the container and the liquid floated on the top.  When this happened the only way to thoroughly re-mix the slip was to sieve it thoroughly several times.

Apparently it is not weather sensitive and can be frozen or placed into extreme heat without affecting the qualities of the slip.  I used to store my gallon tubs of Seeley's slip in the garden shed, which is baking hot in summer, and freezing cold in winter, and yes, the slip did freeze occasionally and it was always a bugger to mix afterwards.

But best of all, apparently Ultra Chic can even be reclaimed, which is a major boon. During a casting session there are lots of offcuts of leather-hard greenware which up till now I've had to throw away as I couldn't reconstitute them without a pug-mill.  However, according to the makers of Ultra Chic, I can now collect all the spare bits from each casting session and simply toss them into an empty gallon container.  When it is full of dry porcelain, the container is filled with water and left to sit overnight. The excess water is then poured off and the resulting sludge stirred then sieved.  This reclaimed slip can be added to new slip at a ratio of 1 part reclaimed to 3 parts new.

Brilliant or what?

Not only that, if I need a piece to shrink more than the normal 17% range I can use pure reclaimed slip and the piece will shrink more in the firing!

I am both amazed and delighted!

Of course, the proof of the pudding and all that.......  It remains to be seen whether these claims can be substantiated in practice, and I'm going to have to do a test firing to see if my the firing schedule currently programmed into my kiln will produce perfect pieces.  However I'm quietly optimistic and looking forward to experimenting.



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