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Why It Goes Off Center?

throwing centering

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#1 glinum

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Posted 12 June 2014 - 06:39 AM

Hello!

I've been doing pottery for more than a year now, mainly with smaller forms. Now I'm learning to throw with bigger lumps of clay - 1.5kg to 2.2kg (3.3-4.8 lb).

 

The problem I'm facing is that the top of a pot goes off center when I'm widening the walls. So I center the clay, open it, pull up the walls to make a cylinder. Then I start to stretch the walls wide from the bottom and at this pointer the top of my pot begins to go off center and the more I widen the walls, the more off center it goes.

I just can't understand what am I doing wrong? The funny thing is doesn't happen all the time. Sometimes the top stays in place when I stretch the walls.

I would be very thankful if someone could watch my video and tell me what I'm doing wrong.

 

I think I have to mention that I'm a selftought potter, I just watched Simon Leach's videos and did what he did.



#2 bciskepottery

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Posted 12 June 2014 - 08:01 AM

Watching mostly from 8:30 on in the video where the wobble starts. Consider using your flexible metal rib to clean the slurry off the outside of the pot, not the rigid wood rib. You can bend the metal rib to the contour of the pot. You seem to do a lot of thinning of the walls on the bottom part of the pot, perhaps leaving the top part top-heavy and prone to wobbling. Also, it looks like you hand may have touched the upper part around 8:39 to 8:41.

#3 Benzine

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Posted 12 June 2014 - 08:41 AM

It also seems like there were a couple occasions, where you put pressure on the walls, from the outside, and quickly took your hands off. The uneven pressure all around, can lead to wobble. Always take any type of pressure off gradually, whether it be during centering, opening, pulling or forming.
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#4 JLowes

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Posted 12 June 2014 - 09:24 AM

It seems to me that the wobble developed in the base and was carried upwards with pulling the walls up.  You were good after centering and pulling out to get the clay ready for wall pulls.  it looked to me like the first pull was good, and when collaring some unevenness of the walls may have crept in.  Around 3:20 it starts to be noticeable and from there becomes more noticeable as the video progresses.  As you continue to expand the form the issue becomes more and more noticeable.  Once this develops it is hard to correct as the form starts to push the clay into more unevenness due to the wobbling. 

 

The continued use of water reduces the strength of the clay, and it would benefit you to learn to use the slip from centering for lubrication instead of more water as you pull the walls up.

 

I recommend getting all of the height of the cylinder before starting to form the walls.  As you gain the height, slow the wheel down progressively.  Clean off the slip before you start to change the shape. Once you start to change the shape, very slowly make changes from the vertical profile.  The clay consists of platelets that need time to move over and around each other, and making small changes helps this process.  Getting too greedy with pulls or shape changes leads to problems.

 

You have done a pretty good job of self training from videos.  Now the nuances need to be addressed.  Ask more questions, as this forum is a helpful bunch.  Good luck with your progression of skill.

 

John



#5 Min

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Posted 12 June 2014 - 10:32 AM

In addition to what has already been posted I would suggest working on getting the cylinder height done in 3 pulls. Clay gets waterlogged and tired when overworked. I get more height when the outside fingertips are actually orientated so they are pushing the clay up, rather than at right angles to the pot, couldn't really see if that is how you work.



#6 Biglou13

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Posted 12 June 2014 - 10:48 AM

(In my best yoda voice). It (clay) doesn't go off center , it is you that is off center....

Bat is off center to start, not a problem. Is batt equally off center at finish? , problem. Try all the above. And throw off the wheel head. There are a few times you remove hands too quickly, Not allowing full rotation. Let the next one dry a bit then cut in half.
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#7 schmism

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Posted 12 June 2014 - 01:18 PM

Being in the learning phase myself,  I found that if i wasn't consistent in bringing my pulls up, like i let up on the force to quickly etc,  that would lead to unevenness in the walls which would 1) start to pull things off center, 2) if i was able to correct it i would often wind up with a wobbly lip resulting in having to trim the lip, or live with the unevenness. 



#8 Rebekah Krieger

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Posted 12 June 2014 - 03:05 PM

Don't be afraid to touch the inner lip of the form when collaring in. I found it best to prevent warping by supporting on the inside what I am attempting to do on the outside.  Another tip that is unrelated is to be confident when touching the clay, be sure of where you want the clay to go and do it.  Not long ago I realized that i was touching the hell out of the piece and not doing much to the form. I am not a pottery expert whatsoever, so hopefully my advice will not screw you up. ;)


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#9 Colby Charpentier

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Posted 12 June 2014 - 06:44 PM

Assuming you're a hobbyist, you're doing great, don't worry about anything, just enjoy your time on the wheel. And don't put very much clay on that wheel. The first thing one notices is you slow the wheel down every time you bear down while centering. You could improve your technique a bit to not be so aggressive, but either way, that wheel doesn't have much torque at all.

 

Also take note you weren't cleanly centered when you moved onto opening, and you could really clean up a lot by keeping everything centered before moving onto the next move. This isn't required for a more experienced thrower that can adjust while throwing, but it's a lot easier to stay centered than it is to correct while learning. Think about having to make a full revolution to effect a full ring of the clay before moving removing your input. Every time you release, you're making partial moves and it's pushing the clay more and more off center.

 

As you work with larger amounts of clay, you amplify the issues you're having. Start with comfortable amounts of clay, and work up from there, if the wheel struggles at all, back down the amount of clay and the amount of pressure you're using.

 

And as suggested, only make the moves you need to. There's no need to pull, shape, and rib your walls multiple times. Pull your walls, shape your pot, rib your pot, be done.

 

But again, be happy with where you are, and enjoy it!



#10 Wyndham

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Posted 12 June 2014 - 08:30 PM

As others have mentioned, the clay is over worked. Study other youtube videos that show proper pulling and collaring. The shoulder of the pot has become fatigued and can't support the upper neck and rim.

You're doing fine, just work on the basics.

Wyndham 



#11 Babs

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Posted 13 June 2014 - 12:23 AM

CHeck out Neil Estrick in this post

 

http://www.youtube.c...h?v=7lllCkLbJFE

 

Just awesome,  Every movement required, no fussing movements. Lots to learn from this clean operator!



#12 glinum

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Posted 13 June 2014 - 06:13 AM

Wow! Thank you guys for all the advises. I will keep practicing and update this topic later, hopefully with better results  :)

 

My wheel is DIY wheel made by someone who has no clue about pottery. It used to have very very little torque. So I made new pulleys to increase the ratio and as a result it increased the torque, but still not enough. I just make the wheel to spin faster so when I center the clay it spins with adequate speed.

The bat is off center but it sits on pins and doen's move, so it's not a problem. I use bats so I don't have to squeze a bigger piece while removing it from wheel head.

 

Just to make it clear can someone explain what is collaring? (I'm not a native english-speaking)



#13 Biglou13

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Posted 13 June 2014 - 07:55 AM

Rib it. ( frog sound).

http://www.sheffield...-Ribs-s/130.htm

I tend to rib. Basically scrape, compress, and dry the clay, inside and out, after initial pull / cylinder Before shaping....and sometimes during and after,

It will strengthen clay

Then I tend to use same rib to shape form
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#14 Pres

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Posted 13 June 2014 - 08:21 AM

Okay, the full critique, from my personal perspective.

  • You have good skills at centering, but need to take just a bit more at the base of the donut to make certain this is centered well.
  • When opening up, you opened up as if throwing a wide canister, yet later you pushed the clay in for a narrow base-this is overworking this stage and setting up week points for later.
  • Your pulling skills are quite consistent, as are your shaping skills. However, when pulling, as the pot gets higher up try cutting down on the water and using smaller finger contact points. Also, you have a habit of what I call "chicken winging". Your elbows are far from your body making you use more muscle to stabilize than needed for the task, bring you elbows in closer to your body.
  • The big problem with your top offcenter comes from the lack of recentering the shoulder neck join on up the neck. I recenter this area everytime I make a shaping move. Oh by the way, you can shape going down or up, does not matter. Recentering the shoulder/neck will help to keep the neck in line. Make certain to use less water on shaping, the more water the more the clay will want to slump, especially with the bulbous form you are shaping that has to support the full neck on top. So do try to cut back on water.

These are my personal observations, they are not meant to be mean, and these are the things I would point out to my HS and adult students when working.

 

"Chicken winging" I have seen in a lot of potters, and often when they start throwing larger, they have problems with bigger amounts. Moving the arms in closer to the body is tough, but has a tendency to stabilize the hands for more even consistent pulls. I don't have a whole lot of arms strength, but find that I can throw 25-30# when needed. If I chicken winged I know I would not be able to.


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#15 Benzine

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Posted 13 June 2014 - 08:54 AM

Very good advice Pres, you should get into teaching!

I agree, tucking the arms, as well as bracing the elbows, is very important. I have my students start with 1-2 lbs, and I explain, even though they are way bigger than a pound of clay, the spinning clay pushes back more than you'd think. I also explain, that even though I know they are strong enough to push around a pound of clay. But keeping that pound in one spot, takes a lot of stabilization from the muscles. Whereas bracing your arms in close to the body, allows you to use body weight, far less arm strength and stabilization needed.
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#16 Rebekah Krieger

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Posted 13 June 2014 - 09:42 AM

Wow pres- your great advice makes me want to do a video and have you critique it.  


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#17 CarlCravens

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Posted 13 June 2014 - 10:00 AM

glinum,

 

"Collaring" or "collaring in" is when you wrap your hands or fingers around the pot and squeeze in (and usually up) to make the pot narrower.


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#18 Pres

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Posted 13 June 2014 - 05:10 PM

Rebekah, no big deal. I used to do this day and day out with lots of students, you learned what to look for, especially if you were confident with your own skills. Everyone throws differently, but there are inherent basics throughout the process-body posture, body bracing, extensions of the elbows and position of the hands and fingers in relation to the clay, depth perception by feel, measuring by feel whether in distance or pounds, equalization of pressures in all stages of throwing and shaping, stable slow motion movements when needed, graduated pressure as moving upward on the form, and so many others that off the top of my head, I can't think of. People may use different fingers to throw, positions, different wheel speeds, or even use other body parts, but those before are basic, intrinsic, and only learned through many hours of practice.  I learned more about my own throwing by evaluating throwing of others and helping them to correct their problems.


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#19 jrgpots

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Posted 13 June 2014 - 07:58 PM

I admire the guts of anyone who freely submits to open critique especially with a video.

 

Jed



#20 oldlady

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Posted 13 June 2014 - 08:32 PM

while watching the video, I noticed that you have a music video as well. I loved the haunting melody.

 

and as far as using English, not only is it a second language for you, but also a second alphabet!  it is amazing to me, I cannot say anything in any other language and admire anyone who can.


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