Friday, 19 December 2008

Shivering - any Suggestions ?

We met another Earthenware potter the other week at a craft fair.
His name is Nicholas Hillyard, he made this cute little jug above.
We got chatting about glaze or slip coming off rims, it would appear that it is a problem both of us come up against from time to time. Unfortunately I did not have a definitive answer for Nicholas so I suggested I would put the question out to the bloggers.
My slip is 100% hapless ball clay, ( I had typed in Hyplas but spell check wanted to change it to hapless, which made me chuckle ). it only happens on a few pieces at random.
Any suggestions ?
Here is a close up of one of my jug handles
and below is the rim of the same pot !

On a slightly cheerier note I made the Wreath for the front door
of the cottage this morning, made from bits I cut from the Garden.
It's all in a desperate attempt to not do the glazing I have to do today
for my final Firing of the year.
I may even go and get my hair cut this afternoon for the first time since August.

5 comments:

doug fitch said...

It's a bit of a bore when that happens. I use hapless 71 too. It can happen if the bisc temp is too high, I fire to 900 and it seems fine. I've seen it happen if the pots are a little too dry when slipped.

doug fitch said...

thinner slip can help too, or a quick wipe around the rim immediately after dipping, with the thumb - gives a nice effect too.

Margaret Brampton said...

I still get this happening to my pots from time to time. To say it is annoying would be an under statement.
I use 60 ball clay, 40 china clay and some of the clay body I throw with. But I think it only happens when I slip things that are a little too leather hard and there is a difference in the rate of contraction and the body doesn't absorb the slip. Of course if you slip the pot when it's too wet the whole thing can just collapse because the water content is too great.
It's very dissappointing when it happens. If it's going to happen it goes as soon as I unpack the kiln so at least I know what's happening.I'll be very interested to see what other people say on this subject!!
All the best

Hannah said...

arghhhhhhh it's hellish. Touch wood not had it for a while. I find i get it on pots that get too hot, when my kiln was getting about 10 degrees hotter at the base all the things on the base would shimmer. I have changed my bisque to 1010 but no idea if it helps. Yes if they're too dry it seems to affect it too. someone suggested to me putting some lead in the slip, haven't done it but it might help. who knows. i certainly don't, i just make it up as i go along.

Christine H S said...

aargh! I found it happened either when the pots were a tad too dry, maybe in a slight draft, or when they just got that little bit overfired, but it seemed to be pretty random and is infuriating. Now I wipe slip off sharp edges like rims etc and even put my handles on afterwards - using the contrasting clay as a feature - which I have seen in some traditional Devonware.

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