Thursday, 20 January 2011

Glaze Test Results

So I've done a couple of quick glaze tests based on some recipes that were given or which I've pinched from elsewhere.  Simple stuff really.

The first is a clear glaze, 80% Lead Bisilicate (LBS) and 20% Hyplas ball clay.  It has a nice creamy colour to it - no crackling that I can see, despite already being filled with hot water.  There are a lot of bubbles in it - I added an extra-thick pour to the patterned areas.  I like the bubbles but I'm not sure if it's a hazard or not.  In the foot ring, there are more bubbles - a bit rougher but it's ok.  I like.

The second one is 80% LBS, 10% FFF feldspar, 10% Hyplas.  I've also added some cobalt to the previous glaze - just a smidgen - and splashed some on the top, to see what it's like.  As you can see, I didn't mix the cobalt in very well - I didn't sieve it.

Again, I like.  Many more bubbles, good colour, nice where thick.

Well, I'm not sure you'll be able to see it in the next picture, but... it's coming away from the rims.  Well, it isn't, but it looks like it is.  There are lines and I'm not sure if it's cracking in the glaze where it's starting to shimmer off, or just marks in the underlying slip.  I'm assuming the former, because the others look ok to me.  Shame.  This is, I think, Paul Young's recipe, there abouts - different clays and feldspars though, probably, so not at all the same in reality.

Lastly, my original glaze - in fact, from the bucket of glaze I used last time.  I like it still - funny yellow though - in the foot ring, went sort of a snotty green, though.  A few bubbles and just one bubble has burst and given me a blister.  But it was much better than before.

I managed to get cone 02 bent right over, and 01 was starting to go.

Not sure what the conclusion is - I like the first glaze - simple - and my original glaze.  But, the pots have a slightly flat feel to them.  Dunno what to do about that.  It felt less so when they were fired hotter and the decoration started to melt in to the glaze.

I think too that I need to consider my decoration a bit more, perhaps, as some of the marks weren't nice.  A black slip would be good too (I've been keeping scrap red clay - turnings and off bits - to slake in to a slip.)  Decoration isn't my forte, unfortunately.


  1. i like em!! like the pouring/loose quality of your deco and glazes....hard to tell without feeling them :P and lovely feet too..

  2. I think these look good Andy. Well done. Once you get a glaze or two that works then you can start moving on. I think you're ready to go. The white slip is a bit too white for me. I have some Mason stains in mine to make it more of a very subtle butter creame color. If you tint the glaze then that would help too.
    I don't mind the bubbles. And that clay has a nice color to it.

    As far as flat pots're right. It's what you get at low temp with these materials. Solution...all those hours you used to spend chopping wood and stoking your kiln, now you have to put that time into the pots BEFORE they ever go into the kiln. It's a trade off. These electric kilns and glazes give us Nothing, so we have to make it happen. Layering is a good idea, thin/thick slip. Leaving some bare clay or unslipped clay. Texture. Have fun, play around. I think you're on to something that is working technically, now you just have to make it yours.
    I'm really happy these came out so well.

  3. Thanks both. Yes, loose is what I do, I suppose.

    Ron, I wonder if the whiteness is colour balance on my camera. The effect is quite creamy and warm, not as harsh as the pictures give. I have to admit that I'd like it a bit whiter actually, for some of the pieces. I'd like to do the opposite of what everyone else has done over the past century and make stoneware type effects in earthenware (I was reading an article by Cardew yesterday which was about why they gave up earthenware and how he ended up doing slipware effects in stoneware.)

    Anyway, as you say, it's a base from which to move forward. Looking around me now, I have all this slipware and it's all layered or got fancy deco on it. I'll have to think of something.

  4. Looking great Andy,
    I do hope you haven't got any shimmering, it's a bloody swine and that's putting it politely. I tend to smash my pots that have that but I brought a couple home and some the glaze pinged right off quite quickly but a couple which have that wierd slightly shiny line on the rims are still fine after a lot of use. I wouldn't knowlingly sell them, too risky if it does come off.
    It's hard to see the glazes from pics, mine sometimes is quite stiff, it needs to melt a bit more but then the bugger shimmers more too.
    Make some more of each, they're looking good.

  5. Thanks H - it's only that one glaze that shimmered - it hasn't come off, just, as you say, those tell tale silver lines. Will go with the simple 80/20 glaze as it seems ok. Doug suggested bisc a bit lower, so I might try that. Got a bisc on at the moment, so more pots to do over the weekend.

  6. Right on Andy. Everything looks different here on this machine. Much better in person usually. Sounds like you have something in mind so go for it. Can't wait to see more.