Lesson #541

[Min]

Lesson #637

 - Don't make the outside of the pot smaller than the inside of the pot when trimming.

Lesson #638

 - Use the tools you have to help determine the thickness of the walls and bottoms of the pots.

 

For lesson #638, this little thing is super simple and it works. Stick a pin into a dowel or whatever then snip it to the depth you want the bottom of the pot or snip off one you already have. Faster than using a regular pin-tool and more accurate for getting an even depth across a wide base. 

 

edit: sorry should have added this would be used when throwing not trimming.

[Pres]

Old trick. . . put a needle in a drill, lightly score with an exacto every 1/4" or 1/8". Place needle in a handle, and you automatically know the depth of the pot when you needle through the bottom with the finger on the inside to feel it coming through.

 

Others have used a thumb tack inside of the pot to let them know when they are getting close. Remove the thumb tack and polish of the base.

 

I have come to the point where I can feel very closely the distance between my hands, when inside and outside of the pot. Trim carefully. Listen to sound of thump on bottom and side walls for thickness comparison.

 

best,

Pres

[Joseph Fireborn]

It just takes practice. I still trim through pots all the time, so don't feel so bad about it. I trim super aggressive. I dont like dilly dallying around. I peel out chunks pretty quick.  When I trim through a pot I just go, "Oh look a new test pot". Then put it in the section for rejects that get crazy test combinations on it. 

 

The best way to avoid it is to have no music or sound going when your trimming. Stop the wheel, tap the foot, listen for that thunk. Once you start doing this enough you can get the feel for it. Also taking it off the wheel and feeling the thickness is good too. Also the more you trim you just know how much you leave on a foot over time. Particularly once you start throwing the same shapes over and over. You just know when it is close.

[Guest]

I've used some woodturning tools I have to gauge thickness on clay pots, I'll take some photos of them and post them. I'll try the pin in a dowel tool and the thumb tack trick soon. Thanks. There are woodturners that do something very similar, I just never liked putting holes in wood since its harder to repair than a hole in clay.

 

While I typically turn wood to around 1/8" - 3/16", I've gone as thin as 1/16" and can't remember the last time I went through the sides of a wooden form. While clay and wood is different, trimming clay and turning wood are surprisingly similar in so many ways. I knew I was trimming too thin about 3 heart beats before it was to late. The sound I heard was exactly like I would hear when turning.

[Marcia Selsor]

First pot I threw in my new studio in March or Feb. flew to the floor after the bat stuck a bit as I was lifting it off the wheel.

[pmeredith]

I refired a awful green teapot I had made, the teapot was a cool shape but the kids at ULM fired it to cone 6 instead of o6 bisque. well I glazed it as a test but didn't like the color, ugly green, well I checked if it would pour nice it did, so I dried it out and took it back to my little studio and put some blue rutile on it. and refied to cone 10 with some glazed pieces, that teapot exploded into about a million pieces and this is my 3rd firing of my new kiln. the only part left that was recognizable was one inch or so of the spout and the green handle. live and learn. I will never refire anything.

[Mark C.]

I refired a awful green teapot I had made, the teapot was a cool shape but the kids at ULM fired it to cone 6 instead of o6 bisque. well I glazed it as a test but didn't like the color, ugly green, well I checked if it would pour nice it did, so I dried it out and took it back to my little studio and put some blue rutile on it. and refied to cone 10 with some glazed pieces, that teapot exploded into about a million pieces and this is my 3rd firing of my new kiln. the only part left that was recognizable was one inch or so of the spout and the green handle. live and learn. I will never refire anything.

Well I would not jump to never retire anything again

My guess is you had moisture still in it (since it exposed and just did not crack)

next time really dry out the piece and go way slow at the early stages since the clay body is already tight.

Live and Learn is the right attitude but never refire is not learning from this in my view.

I have 10 retire pots in men cone 10 kiln going right now . I never explode them-they have about a 50/50 success rate.

[Marcia Selsor]

I have re-fired a few things, sometimes to fix where a glaze didn't work or pinholes. I use a dry paste of the glaze or powder.

Marcia

[flowerdry]

The only refire I ever had explode was one that had had water in it.  It hadn't had water in it in a long time and I really thought it was dry.  I think if I ever seriously wanted to refire a piece like this, I would put it through a bisque fire first to make sure it was completely dry.  Probably I'd just make another.

[oldlady]

you "checked if it would pour nice".  with water, probably.  do not forget to vacuum the kiln for every tiny shard.