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Thursday, 9 July 2009

Just how specific is this darned specific gravity?

So, there I was remeasuring the specific gravity of my orange glaze, making sure it read as it should from a month ago. Good news, it read the same. Bad news, it looked so damn lumpy and so different from a month ago, I really couldn't believe what I was seeing.

To appreciate the amount of frustration I was feeling at that juncture, I must go back 2-3 months ago when I undertook the painful process of understanding my glazes more. With every kiln firing producing various results, I had undergone the necessary cone fire testings to ensure the right controls were in place and that I was firing evenly and consistantly. After cracking that issue (mind you, that took about 4 months....), I started reading up on how to get my glaze consistancy constant (say that over and over again really fast- I dare you).

I started with hyrdrometers and after reading bucket loads of info on, decided against persuing that angle. However, the good people on recommended using SPECIFIC GRAVITY as a reliable method for measuring the amount of water (the consistancy) in a batch of glaze so you can replicate it every time you make up a new batch.

So I eagerly and dutifully tested all my glazes at a thick, medium and thin consistancies to better decide which one was best for the glaze. Once confirmed, I made sure the batches were well mixed and measured the specific gravity accordingly. In fact, I did this three times to ensure little to no room for error.

This is why after re-measuring the batch recently and recording a same specific gravity as before, I was dumbfounded to see a thick muddy pool of glaze. Help!!! Does this mean I cannot even rely on this measurement either? I don't want to go back to sticking my finger in the batch and measuring thickness by just how much of my skin texture can be seen through the glaze film - too much room for error!

Anway, I will proceed. I am ready to dump these glazes once and for all and streamline to one reliable glaze - is there such a thing!?!

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