There is an easier way to do this. Roll out a slab a bit larger than the mouth of the pot. Place a strip of very thin dry cleaners plastic over the rim of the pot. If the pot has a gallery skip that step and just dust with cornstarch/cornflour. Now take your slab and place in on the pot. Gently press down the slab in the middle and working outwards to make an upside down dome, sponge works well. Roughly cut the excess clay off the outside of the slab so the weight of it doesn't pull up the slab. Leave the slab on the pot until it stiffens up then remove it and finish the edge. There will be a mark on the lid from where the top of the pot or gallery was, use that as your line to work from. Also, make registration marks as the pot likely isn't symmetrical. I used to make oval pots / lids like this, it works.
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MinMember Since 31 Mar 2010
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Posted by Min on Yesterday, 11:48 AM
Posted by Min on 05 December 2016 - 08:51 PM
Re turquoise glaze, do you have Britt's Mid Range Glazes book? If you do have a look at the glaze combo on page 110 and again on page129. Autumn's Crystal Matte over Glossy Base 1 with 3% copper carb. It somewhat resembles the look of your turquoise. (maybe run some tests with that at the same time as the naked cylinders tests) If you are okay with a gloss liner then you could use the same Glossy Base 1 and add zircopax to make white.
If you don't have that book let me know and I'll email you recipes and pics if you are interested.
Edit: Do you have a pot with this batch of clay that you haven't used or tested? Could save some time with testing by thoroughly drying the pot out in your oven, weigh it really accurately, put it in a saucepan covered in water and simmer it all day, then let it cool in the water, towel dry it and reweigh then do the math for absorption figure. Obviously not as accurate as using an unglazed piece but should supply some info.
- Joseph F likes this
Posted by Min on 02 December 2016 - 12:29 PM
Yup, lazy susan bearings. It's for a cheese board / lazy susan bottom, nothing complex. I wasn't very clear in my description, I just meant the adhesive is sandwiched between the bottom of the pot and the bearing, not open to the air like tub caulking would be. I have a display rack that holds about 8 of them standing up so I really can't have the bearings slide down. I went ahead and used the silicone last night, I did that before seeing your post this am, fingers crossed. Thanks for the tip re Liquid Nails curing quickly and not to use Loctite.
It's just a bunch of these things that I was doing last minute,
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Posted by Min on 01 December 2016 - 02:11 PM
a few years ago, i read somewhere that i should add ball clay to the recycle because it gets stripped away when originally used. so, i tried adding ball clay while pugging. i think that was the clay that tore so nicely when i made slabs with some of it. i have since realized that the statement is true if the clay comes from a wheelthrowing potter not a handbuilder. so, i just use slurry.
might add some ball clay and make more slabs to get the tearing that sold so well. hmmmmmmmmmmm
Not sure I would do this for clay for functional pots. You are going to change the silica : alumina : fluxes ratios. A little bit of macaloid or bentonite (think ball clay on steroids) will do the same thing without changing the chemistry as much since you use far less of those.
Have a safe drive.
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Posted by Min on 30 November 2016 - 09:27 PM
that's a mess?
little tip, put the piece of foam that comes in the cone boxes under the nozzle end, the clay when leaving the pugger will slide along the board without leaving a streak of clay on the board.
Congrats on your new purchase!
- preeta likes this
Posted by Min on 30 November 2016 - 06:44 PM
The picture doesn't look like much but the neoprene disc works extremely well to hold pots down. Damp sponge on the wheelhead, put the neoprene disc on it then damp sponge on the top surface. It holds most forms except for tall skinny ones with no wads of clay. It also works to hold onto and grab wood batts with foam on top. Sometimes I have to burp the neoprene to get the pots off. The only drawback is you can't tap center as the pots won't slide easily. (I run my finger on the damp top to make a circle roughly the diameter of the pot rim that I will be sticking down to get it pretty close then adjust it if necessary) This one is about 20 years old, no adhesive on the back. For the past few years I've seen them at Seattle Pottery Supply with an adhesive backing to stick them onto batts. These came out long before Giffen Grips and are getting harder to find.
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Posted by Min on 28 November 2016 - 06:30 PM
Sorry to hear of your screw up.
I think the fast cool down is going to have an effect on how the iron red glaze turns out. If it's not too late I would enter a cool down ramp now to match what your previous successful ramp was. It's likely you will get more brown than red otherwise. If it's already thru that ramping down segments then you could try a strike firing after.
Since you only added 27 minutes to your test load hold time I would be optimistic that the glaze shouldn't have run much. No idea if you will get bloating with the clay but hopefully there is some allowance for overfiring.
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Posted by Min on 28 November 2016 - 12:48 PM
I should add in an extra complication to this... matt glazes.
Just speaking with a glaze supplier today and they reminded me that matt glazes also cannot be relied upon to be watertight, so add together a stoneware body that may not have vitrified (at cone 6 or so) with a matt glaze that is slightly porous and you haven't got the greatest of recipes for a watertight jug!
Ummm, misinformation there. For functional stoneware or porcelain pots the clay should not leak even with no glaze. Good way to test for that is to make some flat bottom pots, no glaze inside or out, fire them to whatever cone you will be firing real pots. Fill them with water and set them on a sheet of newsprint. Leave them alone for a week, any wrinkles in the paper and the clay leaks. Glossy glaze, matte glaze or anywhere in between, it can't be relied upon to make a clay watertight. (I learned that the hard way)
Posted by Min on 25 November 2016 - 12:06 PM
I know colours can be off when looking at pictures online but when I compare your raw clay colour to this image of that clay your clay looks quite overfired, I have found that when medium iron bodies get overfired they get that old dead meat colour your pot bottom has. Witness cones are super helpful in checking and monitoring the kilns actual firing.
- bciskepottery likes this
Posted by Min on 25 November 2016 - 11:57 AM
For those of us who spend a lot of time at the wheel, throwing while standing does seem like a better option healthwise. More and more evidence of prolonged sitting not being very good. I know most people who throw get up and move around but I don't think that adds up to the same as standing while throwing.
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Posted by Min on 21 November 2016 - 09:11 PM
I was curious about the lack of midrange rated clays over there so I did a little looking around online for some. In addition to the ones Joel and Sputty found I came up with these 2.
https://www.claymans...[email protected] 1100-1220°C (Cone 03-6) Earthenware/Mid-Range Stoneware, white clay.
https://www.claymans...[email protected] red groggy earthenware that is rated to ^6
Don't know anything about them other than what I read. Wonder if you could get some more detailed info from Clayman? Must be very frustrating have so few choices for this firing range. (they are in Chichester)
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Posted by Min on 20 November 2016 - 12:05 PM
What's the diff between the slip/vinegar/corn syrup mix and "magic water"? Is that a product one purchases?
Magic water recipe is
1 Gallon Water
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