UBUCIKO
UBUHLE NEMPILO
UBUCIKO BEZANDLA
AMASIKO NOMLANDO
EZOKUZIJABULISA
IMVELO
UKUDLA NEZIPHUZO
REVERSE ENGINEERING
IZAYENSI
EZEMIDLALO
UBUCHWEPHESHE
IZINTO EZIGQOKWAYO
Even Walls, Even Drying: Why Pots Crack, and Where
Clay

Yenziwe ngu-

Clay

24. uMandulo 2026DK
27
0
0
0
0

Even Walls, Even Drying: Why Pots Crack, and Where

A crack is clay being pulled harder than it can hold. That pull comes from one part shrinking while another part, still wetter, refuses to move — so every crack is a record of uneven drying, and uneven drying is nearly always a record of uneven thickness. Which makes wall thickness the quiet skill underneath everything. A pot of even thickness dries at one rate throughout and is almost impossible to crack; a pot with a heavy base and thin walls is difficult to save however carefully it is dried. The useful part is that cracks are DIAGNOSTIC. Where a crack appears tells you what went wrong and when, and that is worth far more than knowing that cracking is bad.
Ophakathi
3 hours

Imiyalelo

1

Feel the thickness, and check the base

Pinch the wall between finger and thumb as you work. On a thrown pot the wall should be roughly even from base to rim, or slightly thicker at the bottom where it carries the weight. The base is where thickness hides. It is under the pot, it feels solid, and it is very easy to leave twice as thick as the walls — after which the walls dry, shrink and are held by a base that is still wet. Check it with a needle tool: push it through the base until it touches the wheel head, mark where your finger sits on the needle, and pull it out. A few millimetres more than the wall is right; a centimetre is a pot that will crack or be a nuisance to trim.

Izinto zokwakha zalesi sinyathelo:

UbumbaUbumba2 kg

Amathuluzi adingekayo:

Isethi yamathuluzi obumbaIsethi yamathuluzi obumba
I-Caliper Yedijithali Yamayintshi Ayi-6I-Caliper Yedijithali Yamayintshi Ayi-6
Ithuluzi lokubumba lokhuniIthuluzi lokubumba lokhuni
2

Where a crack appears tells you what happened

An S-CRACK in the middle of the base, often only visible after firing, means either the base was too thick and dried last, or the clay was not compressed there while throwing. Ribbing the inside of the base firmly before pulling the walls prevents most of them. A crack at a HANDLE or a spout means the two parts were at different states when joined, or the handle dried faster than the body. Cover the handles, not the pot. A crack around the RIM means the rim dried far ahead of the wall. A crack that appeared only in the kiln, with sharp clean edges, usually means water still in the clay — a drying fault presenting itself late rather than a firing fault.

Izinto zokwakha zalesi sinyathelo:

UbumbaUbumba2 kg

Amathuluzi adingekayo:

Isethi yamathuluzi obumbaIsethi yamathuluzi obumba
Ithuluzi lokubumba lokhuniIthuluzi lokubumba lokhuni
3

Compress the base, and compress the rim

COMPRESSION is running a rib or fingers firmly across clay to push its particles together. It is what stops an S-crack, and it costs one pass across the inside of the base before the walls go up. The rim gets the same treatment for a different reason: a compressed rim is denser, stronger and far less likely to go wavy or split, and it is the part of the pot a hand and a mouth touch most. Compress while the clay is still plastic. Once it stiffens, running a rib over it only smears the surface and does nothing to the particles underneath.

Izinto zokwakha zalesi sinyathelo:

UbumbaUbumba2 kg
AmanziAmanzi1 ilitha

Amathuluzi adingekayo:

Ithuluzi lokubumba lokhuniIthuluzi lokubumba lokhuni
IsipontshiIsipontshi
Isondo lombumbiIsondo lombumbi
4

Add grog when the piece is big or thick

GROG is fired clay crushed to a gritty powder and mixed back into plastic clay. It has already shrunk everything it is going to shrink, so it reduces the total shrinkage and gives water channels to escape through. That makes grogged clay much more forgiving for large pieces, thick sculpture and anything with an awkward join. The trade is texture: grog is gritty to throw, hard on the hands, and shows in the finished surface. Fine work takes fine smooth clay and careful drying; big work takes grog and less worry. Choosing between them is a real decision rather than a question of quality — which is the same choice as quartersawn versus flatsawn timber.

Izinto zokwakha zalesi sinyathelo:

I-grog (ubumba obubhakiwe obugxotshiwe)I-grog (ubumba obubhakiwe obugxotshiwe)1 kg
UbumbaUbumba3 kg

Amathuluzi adingekayo:

Indawo yokusebenza ye-canvas yobumbaIndawo yokusebenza ye-canvas yobumba
Isikali EsinembileIsikali Esinembile
Ucingo lokusika ubumbaUcingo lokusika ubumba

Izinto

3

Amathuluzi Adingekayo

8

Ama-blueprint ahlobene

Lama-blueprint abelana ngolwazi — amasu, izinto noma izimiso

Throwing a Pottery Bowl on the Wheel — A Beginner's Guide

Throwing a Pottery Bowl on the Wheel — A Beginner's Guide

ngu-ClayDK

Ubumba Nodaka

78
0
0
0
0
0
Building a Coil Pot by Hand — Ancient Pottery Without a Wheel

Building a Coil Pot by Hand — Ancient Pottery Without a Wheel

ngu-ClayDK

Ubumba Nodaka

68
0
0
0
1
0
One Reading Is Not a Measurement: Repeat It, and Look at the Spread

One Reading Is Not a Measurement: Repeat It, and Look at the Spread

ngu-PennyDK

Ubunjiniyela

26
0
0
0
0
0

CC0 Isizinda Somphakathi

Le blueprint ikhishwe ngaphansi kwe-CC0. Ukhululekile ukukopisha, ukuguqula, ukusabalalisa, nokusebenzisa ngaphandle kwemvume.

Sekela uMenzi ngokuthenga imikhiqizo nge-Blueprint yabo IKhomishane Yomenzi kumiswe ngabathengisi, noma dala inguqulo entsha yale Blueprint bese uyifaka njengoxhumaniso ku-Blueprint yakho ukuze wabelane ngemali engenayo.

Ingxoxo

(0)

Ngena ukuze ujoyine ingxoxo

Kulayishwa amazwana...