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Is it me or the wheel?


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#1 DallasGypsy

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Posted 08 March 2013 - 05:16 PM

I seem to have a terrible time opening and pulling up walls on pots on the wheel after getting the clay centered. The pot twists around and then the top part breaks off.

Just for grins, I put a level on the wheel head and found that one side is about 1/8" lower than the other. Is this significant enough to worry about? Is this, perhaps, causing my problem with opening/pulling? Or do I just need to practice, practice, practice?

And, if I want to correct that 1/8" difference & level the wheel head ... how do I do that?


Thanks!

#2 Jess

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Posted 08 March 2013 - 05:42 PM

I seem to have a terrible time opening and pulling up walls on pots on the wheel after getting the clay centered. The pot twists around and then the top part breaks off.

Just for grins, I put a level on the wheel head and found that one side is about 1/8" lower than the other. Is this significant enough to worry about? Is this, perhaps, causing my problem with opening/pulling? Or do I just need to practice, practice, practice?

And, if I want to correct that 1/8" difference & level the wheel head ... how do I do that?


Thanks!


To level my wheel head I use shims under the legs, if your wheel has adjustable legs then you could lengthen/shorten then as needed. As for the pot twisting and breaking off, make sure you are using even constant pressure as you pull up and practice, practice, practice never hurt! :)




#3 Chris Campbell

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Posted 08 March 2013 - 06:07 PM

It sounds like you are using too much pressure as you pull up ... you might be pushing in more than lifting up. If you lift that roll of clay, you should not have to squeeze it that hard.
If you are in your first year of throwing, then it is a matter of practice ... if this has just started happening after years of happy throwing then you might want to get an experienced potter to watch you and correct whatever habit you have developed.
I don't really think that 1/8th of an inch is ripping apart your pots but it never hurts to level it.

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#4 neilestrick

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Posted 08 March 2013 - 06:17 PM

Level doesn't matter. But if the wheel is running out of balance on the shaft, that's a different story. I agree with Chris- it sounds to me like you're trying to pull up too much clay at a time.
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#5 Marcia Selsor

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Posted 08 March 2013 - 06:37 PM

First level the wheel with shims.
But, as Chris suggest, it sounds like you are using too much pressure. Try pulling up slower and leave your pull rings or lines so they are about 1/4" -1'8" as you come up.
Using a sponge or keep the surface slippery but not sloppy.
Go easy in the middle of the pot. That has a tendency to be where things can go thin quickly.
If you get a wobble, use a straight sided rib on the outside to correct it. And go slow. Don't go fast once you are centered.


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#6 DallasGypsy

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Posted 08 March 2013 - 07:46 PM

Thanks everyone. I really appreciate your input.

Sounds like it's mostly me (kinda what I thought all along). I'll have to go back to square 1 and check my posture, placement of my hands/fingers, the wheel speed, the amount of moisture ..... yadayadayada.

Today was really a test after having rotator cuff surgery last October. Shoulder doesn't hurt but other things might not be in proper alignment.

#7 Marcia Selsor

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Posted 09 March 2013 - 06:58 PM

I would say the car is probably balanced. A wobbly bat or wheel head is a problem.
So is an out of alignment tire.

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#8 bciskepottery

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Posted 09 March 2013 - 09:37 PM

Wonder how you would mount your Giffin Grip on that wheel head?



#9 pattial

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Posted 10 March 2013 - 12:04 AM

That's very cool

#10 Pres

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Posted 10 March 2013 - 12:44 AM

It sounds like you are using too much pressure as you pull up ... you might be pushing in more than lifting up. If you lift that roll of clay, you should not have to squeeze it that hard.
If you are in your first year of throwing, then it is a matter of practice ... if this has just started happening after years of happy throwing then you might want to get an experienced potter to watch you and correct whatever habit you have developed.
I don't really think that 1/8th of an inch is ripping apart your pots but it never hurts to level it.


Yes, I agree with Chris. It sounds like you are centering OK, maybe opening off center, and putting more drag with your pressure than needed and thus pulling the clay off center. I used to tell my students that pulling clay was more of a firm caress, with the beginning an attention getting touch to start the roll, and then lessening up on the pressure as you get higher. It takes immense amounts of practice, and you really don't have any prelearning to get where you want to be.

Simply retired teacher, not dead, living the dream. on and on and. . . . on. . . .                                                                                 http://picworkspottery.blogspot.com/


#11 nrsmdwf

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Posted 10 March 2013 - 05:30 PM

I'm not even a wheel potter, but the rotator cuff surgery comment was a red flag to my medical mind .... surely your upper arm and shoulder muscle strength were altered by that whole experience ....

#12 DallasGypsy

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Posted 11 March 2013 - 10:08 AM

Throwing a pot on the wheel of a car just shows that anything is possible. Well ... maybe. Anyone ever try to throw with the wheel upside down? LOL

Yes, the rotator cuff repair has altered things a bit. The range of motion & strength are coming back. What complicates matters more is the fact that I broke the wrist on that same arm about 15 years ago. It's healed fine and is strong but isn't at the "correct" angle. It's off a bit (i.e., can't throw a ball straight). But, I managed to adjust and made some decent things on the wheel. Then the rotator cuff ... aarrgghhh!!

Guess it's like you all say ... practice, practice, practice. And, I'll add ... patience, patience, patience.






#13 Guest_Big Electric Cat_*

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Posted 11 March 2013 - 03:27 PM

In 1954 , Sheldon Carey tried throwing pots upside down; it worked, and he could produce vessels that were taller and thinner than on the regular wheel.
Here's a picture I took OF a picture of Carey throwing. It is from page 170 of Ceramics, by Glenn C. Nelson, third edition. I couldn't find a credit for the original photographer, so I can't give them credit.

I bet he had a lot more problems with quartz inversion than usual. Haha! haha.... ha.

Posted Image

#14 OffCenter

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Posted 11 March 2013 - 03:38 PM

In 1954 , Sheldon Carey tried throwing pots upside down; it worked, and he could produce vessels that were taller and thinner than on the regular wheel.
Here's a picture I took OF a picture of Carey throwing. It is from page 170 of Ceramics, by Glenn C. Nelson, third edition. I couldn't find a credit for the original photographer, so I can't give them credit.

I bet he had a lot more problems with quartz inversion than usual. Haha! haha.... ha.

Posted Image


Thanks for posting this! A few months ago I was talking to another potter about thinking about buying one of those cheap little wheels to throw upside down and he said remembered seeing pics of that being done and that the guy had experimented with lots of different lubricants.

Jim
E pur si muove.

"But it does move," said Galileo under his breath.

#15 DallasGypsy

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Posted 11 March 2013 - 04:02 PM

That's wild! Wonder how much he had to "pull" and how much effect gravity had on the height of his pot. Thanks for posting.

#16 Guest_Big Electric Cat_*

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Posted 11 March 2013 - 04:32 PM

"Thanks for posting this! A few months ago I was talking to another potter about thinking about buying one of those cheap little wheels to throw upside down and he said remembered seeing pics of that being done and that the guy had experimented with lots of different lubricants.
Jim"

I remember reading elsewhere that he had experimented with anything he thought might lubricate - oils, soaps, glycerin, powders. He finally used a flocculant used in the mining industry, Separan 20 ,which is not made anymore. They now have more advanced formulations of Separan.
After I read this, I started my own search for a lubricant, and made some messes, only to settle on using slip instead of water to throw.

#17 Pres

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Posted 12 March 2013 - 09:16 AM

In 1954 , Sheldon Carey tried throwing pots upside down; it worked, and he could produce vessels that were taller and thinner than on the regular wheel.
Here's a picture I took OF a picture of Carey throwing. It is from page 170 of Ceramics, by Glenn C. Nelson, third edition. I couldn't find a credit for the original photographer, so I can't give them credit.

I bet he had a lot more problems with quartz inversion than usual. Haha! haha.... ha.

Posted Image


This was my first Ceramics textbook, and I often would turn to this page when the reading became boring. So impressive.

Simply retired teacher, not dead, living the dream. on and on and. . . . on. . . .                                                                                 http://picworkspottery.blogspot.com/


#18 yedrow

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Posted 14 March 2013 - 11:08 PM

If the top part of the pot is coming off as you pull then the pot is too thin in the section that is supporting the pressure you are applying. That can mean a few different things though. The big thing to keep in mind is that, as a rule, a thin bottom will not support the work necessary to shape a thicker top. That's a pretty good rule. I would recommend getting your pot started with one lift. If you must use two do so, but try to work to where it is just one. Then use a second lift to even up the walls with a slight taper towards the top. Then use your next lift to get height. When you even the piece you create a stable structure to work from.


It is very important to use as few lifts as possible. The best case would be to use just one. The more times you lift the more stress you put on the piece and the further it will drift from your original intent.

Umm, edit note: I only use one lift on smaller pieces and even then they aren't as tall as two lifts.


Joel.

#19 DallasGypsy

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Posted 15 March 2013 - 06:31 AM

Thanks for the reminder, Joel. I get so busy centering myself, remembering which hand goes where. It's good to go back to basics.

#20 Jo-Ann

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Posted 15 March 2013 - 04:50 PM

I had my daughter on the wheel last weekend and she had the same problem. Also, I noticed her hands were moving up the pot too fast, what ever speed your wheel is turning you have to try to adjust your pull to match that speed. Try to remember to anchor your arms if you aren't already. It helped my daughter to have her thumbs cross one another above the rim while she pulled up so they were anchored as well.




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