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#1
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A pugged clay problem
Hi all,
Yesterday I machine pugged some re-claimed clay (as usual), but noticed that the clay's properties werent smooth. The clay could be 'torn' and was ragged when done so. When I pug my clay - I put it through the machine several times to make sure its the same consistency throughout. Although I wedged it really well afterwards I just couldnt get it to feel right - almost as if it had lost its plasticity. The throwing wasnt good either - the clay sounded as if it were a fizzy soft drink, and when inspected, appeared to have very minute bubble holes in the surface; almost like it had fermented. I threw a bowl (almost to completion) and then the side actually tore apart when extending the diameter of the rim. I'm really careful over re-claiming clay and as far as I know - I've been really careful not to contaminate the re-claimed clay in my slop bucket. Anyone actually know whats going on here? I'm wondering if its going to be safe to fire otherwise I risk losing my other ware!! JM (sporting yet another cold - sniff - where's those tissues) |
#2
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A pugged clay problem
Is the pugmill a de-airing type? Could the vacum source be plugged?
-- Lee In Mashiko, Japan http://mashiko.org http://seisokuro.blogspot.com/ |
#3
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A pugged clay problem
No - its not a de-airing pugmill. On the whole, I've never had problems
before, with air trapping in the clay, with it. |
#4
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A pugged clay problem
This clay sounds monumentally tired!
Is this the same clay as you have used before or a very new batch? If it's old stock, how many times has this particular batch been pugged? A cheaper alternative to Yoghurt is Cider Vinegar; I buy a gallon of VERY cheap Cider and leave the lid off for a week, by which time it's turned to vinegar. One gallon lasts me a year. I add a cup-full of this to all my clay, both the re-claim and the new stuff; it does what Eddie says, makes it slipperyererer, 'cos it grows moulds in the clay. Incidentally the Cider Vinegar smells much nicer after a few weeks than the Yoghurt! In times past Potters used make up stocks of clay for the future and keep it under wet sacking in a dark corner of the workshop to allow it to *sour* or mature. They also used to pee on the clay to help the process. Nowadays the clay you get from the supplier is rarely more than a month old at the most, so a properly soured clay is almost un-heard of. A really matured clay is amazing to use; it feels quite different and you can almost throw it round corners! Steve Bath UK In article , JM writes No - its not a de-airing pugmill. On the whole, I've never had problems before, with air trapping in the clay, with it. -- Steve Mills Bath UK |
#5
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A pugged clay problem
Wow, this is both enlightnening and encouraging. I have some real old
clay sitting wrapped up and aging in storage and I was hesitant to even try using it. My shop is not heated and its real brutal to try to work clay in the cold, so I've got some 500 pounds just waiting for warmer days. Right now Spring is breaking here in Tennessee and although I was planning on buying fresh clay, I don't have pug mill money, I'm going give this old stuff a try. Everytime I visit here I learn something new, lol, about the second oldest profession. |
#6
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A pugged clay problem
There is a certain point where clay gets where it just isn't going to absorb
water easily. When it gets this dry I let it dry all the way, break it up (put it in a heavy burlap bag and use a sledge hammer), and drop the pieces (no bigger than a fist is the size I limit it to) int a plastic burlap or canvas bag and put this bag into a 5 gallon bucket with hot water that has had some vinegar added to it (.5-1 Cup?). Let this soak until all the clay is wet through and hang the bag so it releases the excess water and dries to the point of workability. I would be lost without a plaster board to wedge clay into a workable consistency. If I were to mix wet clay with drier clay (which I avoid because it is such hard work), I would only do it in small batches and I would ram wedge, cut and slam, wedge some more and keep on cutting and mixing until I could not detect separate bodies. I would put this in a really wet bag and let it set for a week. Just my 2 cents on how I like to work. Donna "Kees Kroozr" wrote in message ... Wow, this is both enlightnening and encouraging. I have some real old clay sitting wrapped up and aging in storage and I was hesitant to even try using it. My shop is not heated and its real brutal to try to work clay in the cold, so I've got some 500 pounds just waiting for warmer days. Right now Spring is breaking here in Tennessee and although I was planning on buying fresh clay, I don't have pug mill money, I'm going give this old stuff a try. Everytime I visit here I learn something new, lol, about the second oldest profession. |
#7
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A pugged clay problem
Stephen Mills wrote:
This clay sounds monumentally tired! Is this the same clay as you have used before or a very new batch? If it's old stock, how many times has this particular batch been pugged? A cheaper alternative to Yoghurt is Cider Vinegar; I buy a gallon of VERY cheap Cider and leave the lid off for a week, by which time it's turned to vinegar. One gallon lasts me a year. I add a cup-full of this to all my clay, both the re-claim and the new stuff; it does what Eddie says, makes it slipperyererer, 'cos it grows moulds in the clay. Incidentally the Cider Vinegar smells much nicer after a few weeks than the Yoghurt! In times past Potters used make up stocks of clay for the future and keep it under wet sacking in a dark corner of the workshop to allow it to *sour* or mature. They also used to pee on the clay to help the process. Nowadays the clay you get from the supplier is rarely more than a month old at the most, so a properly soured clay is almost un-heard of. A really matured clay is amazing to use; it feels quite different and you can almost throw it round corners! Steve Bath UK In article , JM writes No - its not a de-airing pugmill. On the whole, I've never had problems before, with air trapping in the clay, with it. now, of course, if you lived in Somerset Uncle Steve, you'd use a good scrumpy (cider for the international folks)cos it's likely cheaper than the stuff that folks buy if they don't (live in Zummerzet, that is...) Hugs Eddie |
#8
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A pugged clay problem
In article , Eddie
Daughton writes Stephen Mills wrote: This clay sounds monumentally tired! now, of course, if you lived in Somerset Uncle Steve, you'd use a good scrumpy (cider for the international folks)cos it's likely cheaper than the stuff that folks buy if they don't (live in Zummerzet, that is...) Hugs Eddie Arrr! Now lookee here Young-un I can get a gallon of Thatchers Good Screech (ANOTHER name for Cider) for 'bout a fiver, that'll do noicely! -- Steve Mills Bath UK |
#9
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A pugged clay problem
Lee In Mashiko, Japan wrote:
Is the pugmill a de-airing type? Could the vacum source be plugged? -- Lee In Mashiko, Japan http://mashiko.org http://seisokuro.blogspot.com/ could be the clay is "tired", needs a rest for a couple of months, possibly some (small amount)live yogurt added will help, needs to get some algal growth inbetween the clay platelets so's they is slipperyer, other possibility is that the clay was a bit wet when it went thru the pug, you'll know if this is the case 'cos it'll look "dog-eared" as it comes out of the machine.... Hugs Eddie |
#10
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A pugged clay problem
other possibility is that the clay was a bit wet when it went thru the
pug, you'll know if this is the case 'cos it'll look "dog-eared" as it comes out of the machine.... Hugs Eddie Hi Eddie, I think you may have hit the nail on the head there... some of the clay had gone a little too hard to work with, and so I compensated with very soft clay - which I mixed together to get a happy medium (so for every hard bit, a soft piece went in too). Yes, the result was a little 'dog eared', but I did put it through several times to work it thoroughly. I have gone back to the clay today and it has rested overnight; it's still not right, but not as bad as yesterday. Could this have been the cause of the clay going 'bubbly' too? Thanks for the input (and the hug - I need it at the moment - sniff) JM 'the learning never stops' |
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