Help with Centering!

[ChloeElizabeth]

Hello there!

I am a beginner/medium level potter. I recently joined a membership to a local studio so that I could practice as much possible. Although, I probably should have signed up for a class for some one-on-one personal attention :)

My question is around the basics of centering clay. I know the basic motions, and usually can get my piece close to being centered. However, when I go to trim pieces, the piece never trims centered. For example, some observations: the flat bottom that I am trimming is uneven, the foot rings that I am creating are uneven (one side thin, the other side of the foot wider). Thus, I'm wondering if it's difficult to trim because my piece wasn't absolutely, completely centered before I started to pull. OR could it be a mix of other things? For example, when I pull my walls up, things can get unbalanced or when I center my piece upside down before trimming, maybe I'm not centering it completely. 

I'm sure it's probably hard to answer this question without really seeing my work, but I would love any suggestions/advice on just how I can get more consistent with my centering processes. 

Thank you!

[Hulk]

Hi ChloeElizabeth!

You might pick up some technique watching others, at your studio and online (You Tube).

Starting out, a fully mixed ("wedged") clay ball gives you a better chance - no dryer or wetter bits in there, which will definitely disrupt the flow of clay. From there, well stuck to the bat (or wheel head) such that the clay doesn't shift around ...there's more, of course, just mentioning two factors that don't seem to get much attention.

On to trimming, centering may be a compromise, as pieces may get out of round whilst drying, the lip may not be even, the bottom may have been cut off out of level, etc. Check your center with a pin tool, get as close as possible and reasonable. From there, cutting level and round isn't easy, as the tool will tend to follow the work. Once I've trimmed away the rind (dry-ish skin) and any bulk, I'll use the needle tool to establish a level foot ring and a round (vertical) edge to the foot ring, cutting away the uneven bit. The transition from the foot ring to the wall may take some fudging for a wonky piece, however. In short, use trimming tools such that they aren't following the contour of the work to establish round and level! Hope that helps - interested to see what others may offer...

[Min]

If the rim is uneven when you flip the pot over it won't sit level on the wheelhead and you'll get the issues you described. If you want the rim to be uneven then you need to trim the pot while it's supported on a chuck or chum. These are just humps or hourglass shaped cylinders to fit inside the pots upon which they rest on while you trim, usually made of clay, used unfired or bisque fired. Other solution would be to use a needle tool and trim the rim level when you are throwing it and have finished pulling the walls of the pot. Trim then smooth and round the edge.

Welcome to the forum!

[Bill Kielb]

I agree with @Hulk! There is a skill and the time it takes to throw things taller and thinner but just as important, we likely should stress rounder and more even in height which takes time and practice as well,. Often we stress the tall and thin part and even speed to do it, but rarely do we work on the precision until ................. our skills and observation powers advance.

So to me,  creating clay has slowed down enough for you to begin noticing minor defects  that cause other issues while trimming. This means you will now improve your trimming skills to cope with these issues. @Hulk is spot on with his methods for him. I personally take great care in wiring things off so the bottom of my pots are perfectly level otherwise I will need to trim them level first. Your trimming skills will improve  as well. Watch Hsinchuen Lin trim pots.. He uses the very edge of his tool in an extremely steady fashion to always even out and remove materials. His tool does not necessarily follow the surface, it evens things out. Impressive skill!

When  I finish a piece, the rim is always dead level and the pot as uniform in roundness as I can get it. I undercut the foot with a needle tool about 1/4” very evenly. Now I throw most of my stuff on the wheel head and often speed dry it just a bit with a torch so when I lift it off it remains very round. I set it on a ware board on top of a cheap old paper towel so I can let it dry pretty quickly knowing it will dry evenly and stay pretty round without catching on the bottom . At trim time, I can set the pot on its rim and check the bottom is level. If not, I will trim the bottom level first, then flip over and trim evenly.

Just stuff I do, you will find techniques you prefer that work for you in trimming and throwing. The good news is you have advanced a bunch to now be able to recognize it. 
https://www.google.com/url?sa=t&rct=j&q=&esrc=s&source=web&cd=13&ved=2ahUKEwj7mZbnicDoAhXYQc0KHTm7ACwQFjAMegQIBRAB&url=https%3A%2F%2Fwww.youtube.com%2Fchannel%2FUCgOv-bHeFHnbZE_2fs6YTdQ&usg=AOvVaw0D73pLYQuXx1dhviY9sHoW

 

[Callie Beller Diesel]

Welcome to the forum!

A couple of other things that haven’t been mentioned are that when you begin to lift the clay, make sure that you leave your hands in place for a full revolution of the wheel before you begin that first pull. If that first roll at the base is uneven, you’ll pull your pot off center from the get go. It’s common in folks upping their skill level: they start to be able to move more quickly and surely, but they speed up the wrong steps.

Second: if your foot ring is thicker in one spot than the other, your pot may have shifted slightly in the trimming. Be sure to trim while there is still a little flex to the clay, and it’s not too close to bone dry. Dampen the wheelhead slightly with a pass with a wrung put sponge. Once you have the piece centred on the wheel, make sure you press down the piece a little to vacuum it in place. I find if you rely solely on clay wads to hold the piece in place, things can shift, especially if the wads are soft. Using a chuck or chum as Min suggested also helps with this.

Lastly, to avoid trimming through the side of a piece, don’t center the piece to the rim of the pot, or even the cutoff. The rim will be slightly off center  from the foot even on the most precisely thrown pots. The cutoff, because you’re pulling the wire towards you, will distort the bottom somewhat. Centre it to a point just below where you’re putting the foot rim, and you won’t go through the sides. Or at least you’ll do it less. 

Now that you have a mass of information overload, try some things! Let us know how it goes. 

[liambesaw]

In addition to trimming chucks, another great trimming tool is a foam bat.  No need for clay lumps and uneven rims aren't as much of an issue.  Downside is it's only really useful for plates bowls and platters.

[Rae Reich]

If it hasn't been emphasized in your clay education, one essential part of centering for throwing and trimming is to have your elbows firmly stabilized on your body while you approach and move the clay and your tools. As @Hulk mentioned, the clay will tend to try to draw your motions to it, so you need to be steady. If you are not braced well, the clay will be moving you! 

[ChloeElizabeth]

Thank you everyone! Super helpful tips. Sounds like I need to be more cautious of when I cut the bottom from throwing to be very close to the wheel and maybe trim the rim after throwing as well. A few follow-up questions:

@CallieBellerDiesel Per your first comment, do you suggest I keep my hands (when pulling) to stay in place for a full rotation before continuing to pull them up in each spot? Why would the piece being bone dry affect the trimming? My last pieces were very dry and thus might have been why trimming was so wonky. I do feel like things shift when I just use the wads to keep it in place. Is a chuck or chum my solution? I've never used one...Lastly, can you clarify your last point about trimming to just below where I'm putting the foot rim? Thanks!

@RaeReich Yes! I've been practicing that. However, I still feel like the clay moves me - instead of the clay shaping to my firm hold. Any suggestions? 

[Pres]

ChloeElizabeth, I used to teach HS ceramics, and have seen a lot of beginning throwers over the years. A couple of thoughts about throwing.  If your wheel is moving in a counter clockwise direction, you need to be bracing very strongly with your left arm into you hip so that the motion of the wheel pushes the palm of you hand pushing you elbow into your hip. The movement here should not be at your fingers, they are too weak. It must be the palm right in front of your arm. At the same time, the motion of your right hand should be either bringing the clay into the left hand, or conversely pushing the clay down so that it expands to the left hand. One of the best ways to start the centering is to raise the clay up, and push it down; this actually wedges the clay on the wheel, and teaches you the amount of pressure you can apply without ripping off the clay. This process is often known as mastering.

Back to the centering process. . . once you have the clay centered, where there is no motion against a finger layed lightly at any part of the clay that is not moved when the wheel is moving, then it is time to open up. To open up, yo must still use the strength of both hands against the clay. It is essential to get the opening up where you have interior and exterior areas centered as well. If you're opening up process is not centered then the pot will still be off center with a thick wall on one side of the pot to a thinner wall on the other side. Most of the time to throw a pot for beginners should really be put into the centering and opening up process.

When pulling, it does not matter so much which fingers or part of the hand apply the pressure, everyone is different, what is important is the you have the outside fingers at the beginning of the pull below the inside fingers. This usually happens naturally as the inside of the pot has a bottom and the outside does not. Whenever possible touch the thumbs of the hands together to help you with placement, especially for a beginner as this helps you with judging the spacial positions of the the hands and their pressure points on the clay.  Think of your body and arms as a triangle with the clay being one corner. Always strive to keep the triangle and use the positions of the hands to brace when ever possible. Be certain that you don't rely on your elbows too much, when your elbows get bent, you have a tendency to lose strength, keep you arms close to your body and breath shallowly when pulling. Putting your elbows out away from you body is a weak position that I call chicken winging this habit  will not allow you to improve your throwing or alloy you to throw much larger. Try to keep the elbows close to the body, when throwing lean to the right to allow the left hand fingers to rest properly inside the pot. It takes a lot of practice, but the hours are worth it, especially when you throw that 5 or 6# vase that you struggled with so long.

 

 

best of luck, and welcome to the forum,

Pres 

[Rae Reich]

3 hours ago, ChloeElizabeth said:

Thank you everyone! Super helpful tips. Sounds like I need to be more cautious of when I cut the bottom from throwing to be very close to the wheel and maybe trim the rim after throwing as well. A few follow-up questions:

@CallieBellerDiesel Per your first comment, do you suggest I keep my hands (when pulling) to stay in place for a full rotation before continuing to pull them up in each spot?

@RaeReich Yes! I've been practicing that. However, I still feel like the clay moves me - instead of the clay shaping to my firm hold. Any suggestions? 

The advice  @Callie Beller Diesel gave is very important. Moving hands up before a full rotation will make the piece uneven. Each motion should affect your pot in the same way, all the way around. When you are doing this right, you will be matching your motions to the speed of the wheel. When you need to move slowly, slow down the wheel, don't let the accelerator pedal dictate your moves.

If you follow the suggestions of our @Pres, you'll see the results in your pots.

[Callie Beller Diesel]

@ChloeElizabeth

To clarify:

1) Rae used better words. If you pull the clay up faster than the wheel is turning or at an uneven rate, you'll have a pot with a slightly undulating rim and some variation in the wall thickness. It is easier to trim an even rimmed pot than an uneven pot.  The lower any variation begins in the pot, the more exaggerated it will be by the time you hit the rim. Think steady.

2) It sounds like you're inadvertently pushing your pot off centre while you're trimming it, which will lead to the holes in the side and the foot rim shape you describe. If you're trimming too dry, the piece won't vaccum down to the wheel head, so it's easier to push it off centre when you apply pressure with your tool on the side of the pot.  The harder the pot is, the more you have to put pressure on the side of the pot to cut away the clay, making the situation worse. Using a chuck or even a leather hard clay patty on the wheelhead can help with grip, but a better soloution is to trim while the piece is softer than what it sounds like you've been doing. It's easier on your tools and on your wrists. Aim to have the clay ribbons come off smoothly and just fall away. If they're trying to stick back to the pot, it's too wet. If they're shattering and turning into small crumbs, it's too dry. To get things like bowls to dry more evenly so the rim is a similar hardness to the foot, flip the pots onto a clean bat as soon as they'll support their own weight and let them set up like that.

3) Words not good. Picture better.

[Chilly]

Have you watched any videos?  The best I have seen are by Tim See, he is consistent in his descriptions, doesn't waffle and is clear.  

 

[ChloeElizabeth]

Thank you thank you, all!

@PresI think my opening up process might be a little lazy, resulting in off-centered pieces. Typically, I drill down with my right thumb and then start to pull out and then eventually up. But generally, I start to drill down with my thumb in what I think is the center of the piece. Any advice on keeping center when opening up? 

Also, I feel like I've heard of 2 main styles of centering. 1) Coning up and down and 2) Keeping left hand/meat of palm on outside of clay as a wall and right hand pressing down from the top. Is there pros/cons to either or should I just practice both and feel out which is working better for me? 

@Callie Beller DieselThank you for the visual! I know atmosphere and temperature of the studio alters how long a piece should sit and dry before trimming, but any ballpark days in numbers of how long a piece should sit so it is the perfect amount of dry before trimming? 

Question for anyone! When setting up the inside and outside lines for my foot (with the needle tool), I generally make a guess as to what seems centered. However, that could be off, resulting in a foot that is off-center from the circumference of the base. Any suggestions? Maybe that might not be as important as some of the other pieces mentioned above. 

[Pres]

I used to use my thumb years ago, but as I started throwing with larger pieces of clay I started using anything I felt like to open up. Sometimes even using my elbow when opening 10#+ bowls. That said, i ended up using my middle finger to open up, sometimes supported by the ring finger of my right hand. I use these in position next to my left hand to core down into the clay, or sometimes between the left hand and first finger. It is a matter of how I feel at the time. I core down, then open out so that I have a donut shape attached to the wheel. I make certain to compress the bottom of the clay well, and then make my first pull usually with the sponge in the right hand pushing in on the roll, and my left hand thumb outside pinching toward the middle finger on the inside. This allows me to make strong first pull toward setting up the entire pot.

 

best,

Pres

[Callie Beller Diesel]

@ChloeElizabeth That really is something that's going to be specific to your studio, your own work cycle, the size of the bowls in question, and what methods you use to slow down or speed up your drying. I do this for a full time job, my studio is in my basement and I live in a semi-arid climate and I measure my drying time in hours, not days. My weather app says the current humidity is about 51%. I can throw bowls at about 2 in the afternoon and the rims will be set up enough around 7 or 8 pm, or sometimes as late as 10.  I cut them off their bats and flip them before bed. Trimming happens the next morning (9 ish) if the bowls are in the 1-3 lb range, or as late as the following morning if they're in the 5-8 lb range.  If it's really dry, I might have to lightly cover any 1 lb bowls or mugs that get a foot. If I have a lot of work on the go, or there's a big slab of reclaim, it can slow things down by an hour or two because of the small room and the added ambient humidity.