clay lover Posted March 6, 2011 Report Share Posted March 6, 2011 I am hoping for some help with getting better at this. I have finally conquered the habit cutting the bottoms out... I have gotten better about not leaving a big thick hunk of clay at the bottom. What I would really like to get to is being able to cut them off smoothly enough that I don't need to trim these little things, like bowls and little vases. Does anyone have some suggestions as to how to get really clean bottoms, so that it is a time effective process? Right now, I am using a steel spatula to cut with, lifting the little bowls off on the spatula and laying the spatula flat on the ware board, then slideing the pot off. Is there a better way? I'm having to go back when leather hard and clean their bottoms. Also, how big a pieces do you throw off the hump? Are there any good you tube videos on this? Thanks, all. Just one more thing to learn, because it never ends. One of my goals is to get more efficient, especially with the small, low dollar items. Link to comment Share on other sites More sharing options...
Mossyrock Posted March 6, 2011 Report Share Posted March 6, 2011 Found this You Tube video that seems to address your question specifically. Hope it helps. Link to comment Share on other sites More sharing options...
Idaho Potter Posted March 6, 2011 Report Share Posted March 6, 2011 I thiink that cutting off the hump leaves you with a bottom to trim just as cutting a pot off the wheelhead. That said, the most efficient way I've found is to make an indent where the bottom (this includes 1/4 to 1/2" foot) of the pot is, and use fine string as a cut-off device. I use crochet thread. Carefully place the thread into the indent leaving a short amount of the end sticking out so you can see where you started. Turn the wheel by hand until you have 1 1/2 turns (the starting end should now be at the back of the pot). With the wheel moving very slowly and the string in your hand as close to parallel as possible, pull the string towards your body. Gently lift pot off hump. It takes some practice, but this has worked better than anything else I've tried. I hope you are really compressing the base of the pots so you don't end up with S-cracks. Link to comment Share on other sites More sharing options...
clay lover Posted March 6, 2011 Author Report Share Posted March 6, 2011 I thiink that cutting off the hump leaves you with a bottom to trim just as cutting a pot off the wheelhead. That said, the most efficient way I've found is to make an indent where the bottom (this includes 1/4 to 1/2" foot) of the pot is, and use fine string as a cut-off device. I use crochet thread. Carefully place the thread into the indent leaving a short amount of the end sticking out so you can see where you started. Turn the wheel by hand until you have 1 1/2 turns (the starting end should now be at the back of the pot). With the wheel moving very slowly and the string in your hand as close to parallel as possible, pull the string towards your body. Gently lift pot off hump. It takes some practice, but this has worked better than anything else I've tried. I hope you are really compressing the base of the pots so you don't end up with S-cracks. Thanks for that tip. I watched the you tube video and others and sow several ways to address the cutting off question, all made for better bottoms that I'm getting. and Idid a search and saw others trimming the cut off hump pieces, so I guess not trimming is a pipe dream? A good 'nother question, Idaho. How do I compress the bottom without just making it deeper into the lower uncentered part of the hump? The pressure I would usu on the bottom of a bowl thrown on a bat just makes the hump thrown bottom deeper??? Link to comment Share on other sites More sharing options...
Chris Campbell Posted March 6, 2011 Report Share Posted March 6, 2011 What a timely question for me to answer! I have just returned from the North Carolina Potters Conference where we watched five Master Potters from Jingdezhen, China. The thrower went through 1,800 lbs of clay in two days. Yes, that is not a typo. They had to bring more in for this man to work with! We set out a challenge for him ... how many tea bowls could he throw off the hump in five minutes? He centered 50 lbs of clay and we started the timer. He threw the shape, tapered the clay about 2 inches below the bottom of the bowl until it was loose, lifted it off and smoothed it with the base of his palm in one movement to the ware board. Plunk. A bowl sitting on a two inch clay base. He did not care about the excess on the bottom as it can be easily trimmed away and kept the form steady on the ware board. He threw 18 identical tea bowls in five minutes, then a large bowl and a vase to use up the clay. This was only one feat in a weekend of mind boggling talent. What a thrilling weekend for us all and Potters Council is a proud sponsor of this event. Link to comment Share on other sites More sharing options...
Marcia Selsor Posted March 6, 2011 Report Share Posted March 6, 2011 I use a pointed end of a modeling stick to put a deep groove where I plan to cut off. I also eliminate clay by trimming with the stick as I do this. Then I use my cutoff wire pulling it through the groove. There is no need to trim unless I really want a foot on the piece. Marcia Link to comment Share on other sites More sharing options...
Idaho Potter Posted March 6, 2011 Report Share Posted March 6, 2011 When I'm working off the hump I use clay straight out of the bag so it's a little stiffer than what I normally throw. Try compressing the bottom from inside the pot and also squeezing from the outside the portion just below the pot's bottom. Then, practice, practice, practice. When I first attempted throwing off the hump, I lost 40% of my teacups to S-cracks. Good luck, you'll get it. Link to comment Share on other sites More sharing options...
gallagherpottery Posted March 13, 2011 Report Share Posted March 13, 2011 Bill van Gilder just made a really good video about this including how to cleanly cut off the pots from the hump of clay. Link to comment Share on other sites More sharing options...
clay lover Posted March 13, 2011 Author Report Share Posted March 13, 2011 Since I o posted the first thread , I have been practicing, using the thread and have gotten much improved bottoms. minimal trimming. Thanks, all, for the suggestions. I don't get how to compress the bottoms much, just using a strong pinch from outside befor cutting off. Is there any other way to compress these ' off the hump' pots?? Link to comment Share on other sites More sharing options...
Idaho Potter Posted March 13, 2011 Report Share Posted March 13, 2011 I hope you watched the Bill van Gilder video (excellent!), and when viewing it looked at some of his other short videos. He throws very quickly, but note that he compresses with his fingers to begin with, but also uses his rib for compression as well as shaping, Before notching the hump--prior to cutting off the bowl--try using the rib and gently applying pressure to the outside of the base at the same time. You'll get the hang of this in no time, and it is the most efficient way of throwing multiple bowls or cups. If you end up with S-cracks in some, use them for glaze testing. Nothing much goes to waste in a clay studio. Link to comment Share on other sites More sharing options...
clay lover Posted March 14, 2011 Author Report Share Posted March 14, 2011 Idaho, I did watch it, it's very good. I am a fan of BVG. I've watched several youtube's on 'off the hump'. But none of them directly address the s crack issue. I have this idea that whatever I do to compress the base will just move it deeper into the hump. Must be getting something right, tho, cause the last 20 had no cracks and needed little trimming. I may become a hump crack addict I made a gazillion little bowls before I had to go fix dinner. Link to comment Share on other sites More sharing options...
Diana Denman Posted March 16, 2011 Report Share Posted March 16, 2011 I am hoping for some help with getting better at this. I have finally conquered the habit cutting the bottoms out... I have gotten better about not leaving a big thick hunk of clay at the bottom. What I would really like to get to is being able to cut them off smoothly enough that I don't need to trim these little things, like bowls and little vases. Does anyone have some suggestions as to how to get really clean bottoms, so that it is a time effective process? Right now, I am using a steel spatula to cut with, lifting the little bowls off on the spatula and laying the spatula flat on the ware board, then slideing the pot off. Is there a better way? I'm having to go back when leather hard and clean their bottoms. Also, how big a pieces do you throw off the hump? Are there any good you tube videos on this? Thanks, all. Just one more thing to learn, because it never ends. One of my goals is to get more efficient, especially with the small, low dollar items. I throw off the hump but I keep my pieces smaller and to cut them off I lay a grove at the cut-off point and then lay a string/small cord into one point on the grove. This string has a bead or something likt that to hold onto and then I slowly turn the wheel and the string wraps around the piece and once it is completely around the grove, I pull the string through. That cuts it off rather cleanly. Link to comment Share on other sites More sharing options...
Marcia Selsor Posted March 21, 2011 Report Share Posted March 21, 2011 I have a jpg of how I use the pointed end of a modeling stick to do most of the trimming on the hump before cutting it off. This was from a throwing demo that preceded my large slab workshop in Roswell two weeks ago. One of the participants sent it to me. Link to comment Share on other sites More sharing options...
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