Gonepotty Posted July 1 Report Share Posted July 1 Hello everyone, Seems to be having a few issues with rims warping inwards of large flat dishes during the drying stages (greenware). Just for reference to help with tips: dish is about 30cm wide and the rim height is 6cm. I cover as soon as its thrown and then flip over once the rim can support the weight, but even with covering the dish immediately I am finding the rim still pulls inwards a bit. I am using stoneware, don't throw with very much water and keeping even thickness across base and sides. I am wondering if there is a magic trick I am missing... Any tips greatly appreciated:) Thanks so much Quote Link to comment Share on other sites More sharing options...
Hulk Posted July 1 Report Share Posted July 1 Good question! When you form the rim, try moving it beyond your target - inward and upward - then ease it back to target. If you have (or can find) something to use as a "rounder," that might help. I have a tapered plastic tumbler for cylinder type forms, and a (close to round!) bowl for open type forms; when the clay is no longer tacky, but still damp, it responds to a gentle turn with the rounder. ...check back for suggestions from other Forum members, and please do update with your results. Rae Reich 1 Quote Link to comment Share on other sites More sharing options...
Min Posted July 1 Report Share Posted July 1 @Gonepotty, could you post a picture so we get a better idea of the problem? Quote Link to comment Share on other sites More sharing options...
Roberta12 Posted July 1 Report Share Posted July 1 Yes, a picture will help. Years ago I was throwing some wide shapes and every single one warped. Rather oval. Someone on the forum suggested that I look at how I was wiring the pieces off the bat. I realized I was pulling towards myself rather aggressively and since it was soft Bmix, I was actually warping it. I do seem to have that issue once in awhile if I am getting in a hurry. Especially with porcelain or softer, smooth clay. Rae Reich 1 Quote Link to comment Share on other sites More sharing options...
Gonepotty Posted July 2 Author Report Share Posted July 2 Unfortunately I have reclaimed all the distorted pieces but have tried to show the issue in a drawing... hope this is helpful Quote Link to comment Share on other sites More sharing options...
neilestrick Posted July 2 Report Share Posted July 2 The lip is going to dry much faster than the flat part, and it shrinks inward as it dries. Wrap the lip with a piece of plastic to slow down the drying. Leave the flat part uncovered until it has set up enough to flip. Caution tape works well for wrapping lips. Pres 1 Quote Link to comment Share on other sites More sharing options...
Gonepotty Posted July 3 Author Report Share Posted July 3 22 hours ago, neilestrick said: The lip is going to dry much faster than the flat part, and it shrinks inward as it dries. Wrap the lip with a piece of plastic to slow down the drying. Leave the flat part uncovered until it has set up enough to flip. Caution tape works well for wrapping lips. Thanks so much Neil. I will give that a try Quote Link to comment Share on other sites More sharing options...
Pres Posted July 3 Report Share Posted July 3 Unless the form requires that 90 sharp angle, try a curve that takes a little more space but evens out the stresses. best, Pres Babs and rox54 2 Quote Link to comment Share on other sites More sharing options...
Gonepotty Posted July 4 Author Report Share Posted July 4 10 hours ago, Pres said: Unless the form requires that 90 sharp angle, try a curve that takes a little more space but evens out the stresses. best, Pres great idea! thanks very much Quote Link to comment Share on other sites More sharing options...
Hulk Posted July 4 Report Share Posted July 4 Placing the ware on a plaster bat/slab should speed along drying of the bottom (I use plaster bats for drying more than for throwing!). Bill has mentioned placing damp ware on a piece of paper - similar principle? Quote Link to comment Share on other sites More sharing options...
Min Posted July 4 Report Share Posted July 4 Another thing to try would be to put the pots back on the wheel a few hours after throwing and press the wall back out again. When I make large platters I need to do this with the clay I use. Like many things in ceramics it sometimes takes different approaches to solve an issue. Great tip on using caution tape Neil! Pres 1 Quote Link to comment Share on other sites More sharing options...
Magnolia Mud Research Posted July 4 Report Share Posted July 4 I solved this "problem" by making the edge slightly leaning opposite of the way the drying moves the rim; the rim then will be straight up. my memory says I made three different pots each a little different from the others to find how much to move away from vertical. the idea is if the edge leans left when drying then make the edge lean right when you make it. LT Bill Kielb 1 Quote Link to comment Share on other sites More sharing options...
Bill Kielb Posted July 4 Report Share Posted July 4 The ware is going to shrink, the open end without constraint will almost always bend inward or decrease the initial angle. For plates often the finish firing and gravity will help them settle back a bit. @Magnolia Mud Research is spot on and in my experience and what I was always taught, potters need to learn how much to over-bend this during throwing to get a finished result for their clay, their ware shape…. Testing! Quote Link to comment Share on other sites More sharing options...
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