Trimming Issues

[clay lover]

Very cool.  I love when people think outside the box.  Often, when I'm trying to get some weird thingy invented, I wander through Lowe's sort of  in a trance, absorbing impressions of tools and materials.  some idea will come into my mind while I'm there.

[alabama]

I have been making long neck bottles and vases.  I have been unable to get them to stay put when trimming. The bottom of the vase is larger than the top, so they tend to not hold steady even if I use clay to hold it still.

 

Hey,

      It sounds to me that the vessel may be too dry to stick to the bat or your tools might be dull and you're compensating by pushing harder than you think.

I make 16th century copies of Bellarmine jars and 17th c. jugs which should be similiar in shape to your long neck bottles.  As soon as my vessels come off

the bats I palm in the bottom and cover with plastic.  I trim from the top down, while the clay is still "tacky".  I allow the weight of the jar to hold itself in place.  If by chance I need tabs of clay to hold the foot in place, its usually slip from my bucket wiped along the foot and bat.  You just need something to hold

the vessel in place temporarily.  I don't believe in Giffin Grips for a couple of reasons..

1. They cost money.  2. They only guarantee that the base is centered.  And since I trim everything right side up, that doesn't seem to work for me.

And if you turn the vessel over to trim a foot, then only the rim is centered.

I do have to re-center 2 - 4 times as I trim from top to bottom, but that is ok since otherwise, I'd trim one side thinner than the other.  I have used Giffin Grips and chucks in the past, but now see no use in them.

 

Also, check the dullness of your trimming tools.

Keep us posted,

Alabama

[Pres]

'bama, a little correction here when dealing with the GG. When using rods and pads the pot is centered at the point of the pads on the pot, not the rim.  At the same time, when trimming something like a bowl or a plate the pads at the base work well and quickly. To trim a stem and bowl and then assemble on the wheel the GG works very well and very quickly. I have trimmed chalice bowls using water or even clay chocks, then assembled the stems on(I  always trim stems first) and make certain they are centered and level in that way. However the amount of play at the top of the upside down chalice would often break the bottom chock hold or the water seal. GG holds firmer. But then, maybe it is only me. . . .

[hantremmer]

On 4/30/2014 at 2:56 PM, Marcia Selsor said:

You could improvise by making a chuck from a coffer can or bucket, center it secure it with clay, put a thick coil on the rim and trim it to evenly support you pots. Making chucks in the long run is a good idea and good to have the right tools when you nee them. Mea's trimming upright is also a good time saver.

 

 

Marcia

Has anyone tried doing this but filling the bucket with sand, or some other granular material, to hold the pot in place in the can?

[Mark C.]

spinning bucket of sand what could go wrong?

[hantremmer]

I think bucket was the wrong word  - I meant more of a coffee can or empty an empty paint tin.   I wonder if the clay around the bottom of the tin and the sand would be heavy enough to keep the tin rooted while trimming, assuming one doesn't trim too quickly.

The reason I thought of sand is because it would fit around the pot perfectly if it was packed in..  A sort of cross between a chuck and a giffin grip. 

[Callie Beller Diesel]

The sand would shift somewhat under the centrifugal force and not hold the pot steady, especially when you're applying lateral pressure from a trimming tool. The pot would wobble, kind of like when you use clay wads that are too soft.  Also, the sand would mark up the pot if it was still damp enough to trim. 

[oldlady]

giffin grip has many uses, i love my giffin grip.   had a face to face discussion with mr Giffin, the inventor of the grip at the tampa NCECA.  i was demonstrating the new Bailey quick trim tool which mr giffin was sure would replace or compete with his tool.  he was NOT happy.   the quick trim does not center, it just holds pots in place.

i only use the base pads also, pres.  and i use it several times for each highly decorated carved pot. after putting a foot ring on a bowl or thingy,  the next is to apply slip.  when all of them are slipped, i band the top and bottom to contain the design, and divide the pot into even spaces for the design.  it is a great tool for my purposes.   i never use the sticks.

another use for a bucket and giffin grip is to stir glaze.  if you think sand in a bucket whirling around is unstable, think what an almost full bucket of glaze could do if you were not carefully holding a stirring stick against the inside wall and running the wheel slowly.  does a great job of thoroughly mixing to a uniform consistency.

who uses tools for only their intended purposes, anyway?

[Stephen]

On 4/29/2014 at 9:53 PM, Mark C. said:

If you do it now it will be a crutch and you will never learn the right way.

I get what you are saying and agree BUT isn't it kind of like a calculator for math tests in college. They now let you use one because presumably you would always be able to in the real world 

But of course it could be embarrassing if you are forced to demo trimming  sometime without one available.

[hantremmer]

GOod

22 hours ago, Callie Beller Diesel said:

The sand would shift somewhat under the centrifugal force and not hold the pot steady, especially when you're applying lateral pressure from a trimming tool. The pot would wobble, kind of like when you use clay wads that are too soft.  Also, the sand would mark up the pot if it was still damp enough to trim. 

I see what you're saying, Callie.    I made a chuck today, but beforehand I had to trim a 7" vase using wads of clay around the base and stuck to the side vertically, like caterpillars crawling up a tree.

It was a pain the arse.  The vase kept shifting, the clay wasn't holding as firmly as I wanted.   It's made me think more seriously about getting a Giffin.   Reading about it, it seems more like its use is in being a multi-form chuck.

[hantremmer]

Here's a potter whose work I like using a Giffin Grip - to hold a chuck.

 

 

[Mark C.]

Chucks are easy to make-I used to use them a lot. Now I use my 3 giffen grips, set up various ways.

For non production work I recommend making chucks. Also tap centering will go a long ways on trimming faster.

Tap centering is a skill I think every potter need regardless of what they do with clay.Most do not spend the time learning it. Its worth it to learn .Its just like learning to ride a bike-later in life you need that skill at some point.

[hantremmer]

Centrening isn't he main issue I have; it's getting the pots fixed to to the wheel and having them stay where.  Too often they start to slide.  Using wads of clay seems to end up warping the pots or pulling bits of the rim away. 

[Mark C.]

1 hour ago, hantremmer said:

Centrening isn't he main issue I have; it's getting the pots fixed to to the wheel and having them stay where.  Too often they start to slide.  Using wads of clay seems to end up warping the pots or pulling bits of the rim away. 

This sounds like your pot is not yet firm(dry) enough. If your warping pots dry them more 1st .If the wads are tacking pieces of the rim away the rim is to wet or the wads are to wet.

These are the only two issues that speak to to wet -its one or the other.

[hantremmer]

Thanks Mark.   I did think the pots being a bit damp might have been an issue, but I've also wondered about the wisdom of trying to stick a pot with a very thin rim onto the wheel.

I'm thinking about ways to improve process in my studio, such as it is, so I have a better handle on drying pots and trimming them before they start to dry out *too* much.   I'm having work done on the studio, so everything is in flux so it's hard to seet down a system and test it.

[Mark C.]

Trimming pots well requires exact timing of when they are just right moisture wise to trim.Yes you can not pay attention and trim to dry or wet but each will have its own set of issues.