[Ren]

I noticed that most times when I'm throwing, I always end up with a lump at the rim, or some other kind of uneven quality, but mostly a lump. How does this happen? The rest of the body will be uniform, but my rim will have a problem. I pinch and level the rim every time I pull, but no matter how smooth it goes the whole time, by the end there's a lump in it. And then I end up having to spend extra time and effort cutting off that section, repulling, only to find another lump. I'm guessing it's my technique at the end of the pull. Maybe I'm doing something wrong at the very end right as I'm leaving the rim?


Also, I've played with the throwing stick tool, and have a 50/50 record with it. Sometimes it works awesome, but other times, all it does for me is scrape out tuns of clay on the inside, and making uneven lines inside. I'm assuming the stick should be wet? How fast should I use it on the inside? Any other tips?

[yedrow]

Without seeing what you are doing I can't really say. But, my guess is that your opening isn't in the center. If it is a little off this won't be noticeable until the end when the extra clay (the wide side of the elipse) gets to the top. This is fixed by practice and good technique. The hole can't be in the center if the clay isn't centered. I think Tom Turner has a video that has some good recommendations on centering. Here is a decent video. Though it doesn't address the early struggles of a beginning potter, it does demystify the problem of centering.

http://www.youtube.c...&feature=colike

[Mark C.]

This will be hard just to talk about
When pulling up the wall when at top use your 3 fingers to level off the top-Robin hopper has the tiger move mine is three fingers that smash the lip together as one. Do not let lumps appear so fix them before they appear.
Mark

[clay lover]

Been there, Done that

I will bet it's not at the end that you have a problem, but at the beginning. The opening has to be truely in the center of a truely centered ball, or there is more clay on one side of the ball than the other. No amount of leveling, cutting off will fix that, since it keeps coming from the ball of clay every pull.

More time at the wheel will address that. Has anyone centered a ball well and then let you FEEL it turning on the wheel? If it is well centered, it will seem to be still, while it is spinning. If you can feel it turning, it's not exact.


I am assuming you mean a high spot, feels sort of like a traffic bump? not a chunck of clay burried in the rim?

[Ren]

Yes, exactly. Maybe I have to take a step back and go back to basics. Maybe what I thought was right in centering, is wrong, and I've programmed myself to think it was right.

[GEP]

You said in another thread that your wheel is 10 years old .... it's possible your wheelhead is loose or unlevel. I recently had an issue where my wheelhead was loose, it was making a knocking sound, and I also had a single persistent lump appearing on my rims.

Mea

[Ren]

It seems to be turning evenly with no noise, or noticable wobble. But I'll take a closer look just in case. The wheel is 10 years old, but was barely used by the first owner, and never used by the second owner. I'm the third, and the belts looked practically new on it, but maybe a drop in its lifetime could set it off center, too.

[Dharsi]

While I find Simon very helpful, I sometimes fall asleep waiting for him to get to the point. Watching the wheel spin around always puts me to sleep. I found this vid very helpful as well. http://www.funkefire...eo/center.shtml

[Lucille Oka]

If you can, provide a picture of what you are talking about.

[Marcia Selsor]

When I teach beginning throwing I explain that unevenness in centering comes out at the bottom. Use a tool to even the uneven excess on the bat.
When opening , hold your hands steady for several rotations when you reach the low point inside the lump before pulling up.
When pulling up slowly, hold steady and have the finger marks more horizontal than vertical. Uneveness comes out at the top once you start pulling up and forming.
Use a rib to compress the walls into even thickness if you have uneven walls and trim the top with a pin tool. Repeat as you need to.
Marcia

[yedrow]

Marcia Selsor, on 15 July 2012 - 08:54 AM, said:

When pulling up slowly, hold steady and have the finger marks more horizontal than vertical. Uneveness comes out at the top once you start pulling up and forming.
Marcia

This is good advice. If you can brace your arms as much as possible, and your fingers/hands against each other, you can get a smoother lift. You can think of the wheel as being an electric screwdriver, and the throw-rings as being the fluting on a screw. If those rings are nice and even, and close together, the walls of your pot will be more even. I may be making a video of me making mugs this afternoon. If I do, look for me posting it. If I can remember I'll try to address your problem at least as I'm perceiving it.

[Heidi]

If centering is not your problem, it could also be air bubbles in the clay.