QotW: How do you finish the lips of you vertical pieces?

[Pres]

Last week we explored a little about feet on vertical forms, and alluded to the importance of lips on vertical forms, mugs, cups, pitchers, vases etc.

Which of the following profiles would you attribute to you forms? Do you use more than one profile, or do you have a profile that is not listed here as in 7.

I think most of us started out with something like 1 or 2, when beginning to throw, and often maybe felt that wasn't enough and went to 4 or 5. Just my thoughts.

QotW: How do you finish the lips of you vertical pieces? Please explain, and provide pictures if needed.

best,

Pres

[Chilly]

I don't throw, therefore make few vessel type pots, but when I do, I think about this:

However......  I have two favourite mugs.  One of them I can fill with hot drink, and carry it upstairs in total darkness and put it down without spilling a dropl  The other sloshes around and I have to put a light on and carry it with total concentration.  Mug 1 is shaped like #6 with a narrower neck than body, mug 2 is like #2 but more pronounced - it is a "gardener's mug and shaped like a plant pot.

Shape affects function as well as being pleasant to the eye.

Edited October 9, 2023 by Chilly

[Hulk]

I'm using several of the profiles depicted*!

For more vertical lidded jars, something like #1;
bowls, generally like 2 and 3;
for drinking - glasses, mugs, tumblers, cups, etc., something like #4,5,6, where the recurve is slighter, but perceptible when the eye is level with the rim

An elderly gentleman's son asked about designing a bowl that would assist his father in loading his spoon, so, the "helper bowl" - where the wall curves in somewhat at the top, which isn't particularly helpful when one tips the bowl up to drink from, but it does help with loading the spoon ...and guarding against spills.
Several variations of lidded forms have a more severe incurve, e.g. the teapot.

In general,
   trying "work" the rim only as much as necessary, this from trying to limit the bumpy/gritty feel that sanded/grogged clays exhibit when the finer particles have been worn/washed away;
   encourage accumulation of slip on the rim - leaving a bead of slip when ribbing off the outside, same when sponging out then smoothing up the inside;
   definitely distributing the slip evenly (somewhat) with the chamois as a final step on the rim proper**;
   smooth the rim of slip on the inside with a fingertip and move the pull-off mark down a centimeter or two;
   smooth and shape the outside just below and up to the rim with a frosting spatula;
   use the same spatula to reduce the rim of slip into a spiraled tool mark;
   post bisque, sand any burrs smooth***;
   after pour in/out of liner glaze, dip the rim to accumulate a thicker layer of glaze on and just below (on the inside) the rim****;
   wax, cut, and sponge the liner to outside glaze transition (per Tony Hansen's "Liner Glaze" article and video clip).

Raw wares:
 

The frosting spatula which is a favorite tool. It was used here to smooth and shape the outside wall just below the lip.
That's where the lip "parks" - a critical surface, imo.
In the case there's a ridge of slip at the bottom of the arc, I'll use the spatula to form a diminishing spiral down the side.
Wow, the camera "sees" more that I do! The rim treated thus will usually hold a nice bead of glaze.

Here there was a rim of slip below the rim band, hence the diminishing spiral ...which matches another bowl from yesterday's session.

*Currently; there's been some evolution - there may yet be more.
**A potter named Adam makes the point in one of his YouTube clips that the chamois merely distributes ("...dispersing that damp clay...") slip; to smooth, burnish, "compress" and/or tool the clay, he uses a strip of plastic bag, which removes the slip and smooths the rim. Perhaps leaving the slip does weaken the rim? idk
***outside, with shop vac and mask for me, buckets of rinse water, time, sun, and wind for the wares
****even the stiffest glazes seem to move down a bit, especially at the rim

Edited October 13, 2023 by Hulk
images and even more commentary

[Rae Reich]

+1 for using a strip of plastic bag to compress and smooth the rim

Edited October 12, 2023 by Rae Reich

[Callie Beller Diesel]

21 hours ago, Hulk said:

Perhaps leaving the slip does weaken the rim? idk

I think it depends on the clay body. If you’re working with a really fine toothed clay that’s prone to readsorbtion, I could see excess slip possibly creating some structural weaknesses. Scale might play into this too. If the potter was Adam Field and he was talking about his larger Onggi jars, rim cohesion is going to be a bigger structural integrity consideration on those pieces than on a mug.

Personally I use chamois to smooth out the rim, but I also shape everything with a metal rib. That doesn’t leave a lot of excess slip behind, so redistributing whatever remains is just hiding whatever coarse particles lurk.

I think an entire weekend workshop could be taught on feet and rims. What I use for a rim tends to be very piece specific, and what the pot is supposed to do. For bowls used in the kitchen, i like a rounded or otherwise beefed up rim that is chip resistant. For mugs, I make a round rim that I then create about a 30* angle on the inside that helps cut off liquid flow. Still chip resistant, but a nicer feel for the user. It also makes for a clean liner/outer glaze demarcation. Jars with lids have their own functional considerations as well. Those tend to be more vertical, because I don’t want the gallery warping inwards and trapping the lid in the firing. 

(I have to get into the studio, but I’ll try and get some pictures to upload later.)

[Pres]

Lately I have been using the web of my first two fingers to compress the lip, Used to use the chamois or a piece of folded paper towel, but would not be able to find the chamois all the time. At times would use a fishing float on the chamois to let it float in the water bucket. Over the years have used nearly everything possible to compress lips, just to see what I liked to use.

 

best,

Pres