Monday, 21 February 2011

Start the week with a wrong 'un.

I've been quite keen to get one of these larger jars that i've been making through the whole process.  So to help this, I put a couple of them on a radiator on Friday, to see if I could speed up the drying process.  Well, one of the pair - my favourite of the two - just ended up cracking on the base, but the other appeared unaffected.  So I bisque fired it.

The result.  A small s-crack in the base.  That's ok, I thought, I'll just glaze the pot all over.  So I did.  And here it is, fresh from the kiln this morning.

To be honest I'm not that pleased with it.  I like the decoration, and I like the fact that the slip was very wet when I did it.  But the glaze has no depth.  In fact, I put the glaze on really thick and all you can see is thousands of tiny bubbles.  So much so that, where they are most prevalent - at the base - the glaze is almost opaque.

Add to this that the glaze has shelled from the rim

And the base looks like the surface of a distant planet, and it boils down to not being good.

I largely wanted one through the process so that I could take photos, for a couple of fairs I'm going to apply to.  But I'm not even sure it'll do for that.  So it's back to the drawing board.

I have mixed up some more glaze using a lower-silica clay.  In fact, the glaze is 5Kg LBS, 1Kg Grolleg, 125g Hyplas, 100g Bentonite.  I included the hyplas because it is the slip clay.  The grolleg has much less silica than the hyplas clay so should help the glaze fit.  I haven't tested it - it's a complete punt really - and will probably end in disaster.  But... other recipes I've seen use china clay quite a lot, so we'll see.  The main ingredient is still LBS by a long shot, so it might not make any difference.  I might need a higher proportion of clay.

There were a couple of other pots in the firing.  Although I'm not sure about the shape of this bowl anymore (I've got seven others to fire - they're more rice bowl than anything) I like the patterning.

And these two cups came out pretty ok.

Of course, given what I know about the glaze shelling, I'm not sure whether to risk selling these, as you never quite know when the shelling will happen (so far, it's always been when the pots have come out of the kiln.)  So I think I'm not firing anymore functional ware until I know it's fixed.

In fact, my next project is cheap and cheerful terracotta flower pots to sell on the side of the road.  Thinking I might grow some veg plants to sell too - I can usually do growth to seedling level - it's after that that i have trouble.

1 comment:

  1. I quite like the cups andy, maybe just some more research on the work you want to make and sorry testing is crucial...