boobyagga@juno.com on thu 3 nov 05
hey guys. so far everything that has been said previously is right on th=
e money. however they are leaving out the physics of clay...just a few t=
hings that i have found invaluable while throwing. i regularly throw obj=
ects 1-2 feet tall with a daimeter of about a hand width and a wall thic=
kness of anywhere from 1/8th of an inch to 1/2 inch....so i have seen th=
at anything is possible. you just need to know how to make the clay work=
for you...and ALOT of practice.
first off...clay particles are hexogonal shaped with water molecules sus=
pending the whole solution...this allows the clay particles to move arou=
nd freely while still retaining an electron attractment to keep all the =
particles together. =
problem 1: deflocculation. a deflocculant destroys the polarity of water=
...causing the electron attractment to decrease....this causes the clay =
to push away from itself and become more fluid than it really is. someti=
mes natural bacteria or impurities in some water you use (if you acciden=
tally get some glaze in water for example) can cause a whole barrel of c=
lay to slightly defloc. this would make it so that as you pull higher...=
the density of the walls go down because there is less resistance for th=
e clay to push against itself....so it reaches a maximim height regardle=
ss of technique....this is bad. you may need to clean your clay barrell.=
..hope not...thats not fun.
problem 2: water tabeling out: as i said clay particles are suspended in=
water...not the other way around. this means that as you go higher/ thi=
nner with your walls...the percent of clay particles to the percent of w=
ater particles actually decreases. they become spread out and line up in=
to flat platelets. how fast this happens depends on the water content of=
your clay body. for each clay body and water content there is a specifi=
c grey line where, once reached, the clay WILL NOT go any taller. as you=
pull up...the clay particles spread out...and then slither their way ba=
ck down due to gravity. often this will cause buckling in the pot. you w=
ill leave a pot you think is beautiful and come back to the pot buckled =
and warped on one side....thats because that side has water tabled out a=
nd has gone back to its maximum height. this is not something you can st=
op...just something you have to be aware of...and do some testing with d=
ifferent clay bodies...and work with more dry clay. in fact it is an exc=
elent idea to keep a hair dryer handy around the studio. i find mine in=
valuable for throwing thin and tall.
third problem...and the one i have found most helpful in throwing tall:
osmosis of water into the pot: for throwing, water =3D bad. nice litt=
le rule to live by. water causes clay to go soft and slump and warp into=
odd shapes. but water is a necessary evil. we have to have it to lubric=
ate the pot and throw with. =
so what happens when we put water on the pot....the water actually diffu=
ses into the pot...mostly the surface platelet...and turns that platelet=
into slip....which is more lubricated than water itself. this allows us=
to turn the pot without frictions. however...given time...that water di=
ffuses further into the pot...into the layers that our fingers dont reac=
h and need lubrication...this causes the whole pot to go soft instead of=
just the surface...and this then causes the pot to water table out alot=
faster. pure water diffuses into a pot very very fast. this is because =
of concentration differences. the outside of the pot has a high concentr=
ation of water...the inside has very little water...and a difference of =
concentration will allways and forever diffuse from a higher concentrati=
on to a lower one...and the higher the difference the faster the diffusi=
on. in other words...water leeches into a pot very fast. =
solve this by using slip as water. i know we all love a clean nice work =
station...but that dosent really agree with pottery in the first place. =
find yourself a very large nice container...something like a small trash=
can. use that to put your water in. fill it about half fulll...as you t=
hrow pots take the slurry that forms on the pot and on the wheel head an=
d put it in the water...dont just let it slosh out into the splash guard=
(if you use one...that is problem 4)...use a sponge and put it in the w=
ater. in a short time you will have the best slip you have ever used in =
your life. this slip has a very low concentration difference to the pot =
which means the pot stays drier all the way through. now when you are do=
ne throwing for the day dont throw it out. simply take the bucket and pl=
ace it on a shelf and cover it for use the next day. first time i tried =
this i though well in a day or so ill have wayy too much slip in my buck=
et and ill have to empty it....no you wont. when you throw the clay with=
slip..most of the clay particles actually bond to the surface of the po=
t...so you end up using the water and slip in the bucket...every day you=
will probably have to add a few cups of water depending on how prolific=
you are with throwing due to the depletion of clay in your bucket. =
this is by far the most helpful i have found. it instantly helped me mak=
e the walls thinner and taller....using less clay and improving efficien=
cy. and they look better too ;-)
so my last solution. =
ditch the splash guard. clay is a messy thing...youre going to have to c=
lean up a little anyways. instead use a large sponge....position the buc=
ket of slip close to the spinning wheel head and wedge the sponge in bet=
ween the wheel head and the bucket of slip...this is why you need a big =
bucket...it needs weight so that it dosent just throw your sponge every =
few seconds. this sponge catches all the throw off water and slury and w=
ill eventually fill up with junk. then just squeeze it into your bucket.=
simple. =
now the reason i do this...and i dont have any proof that it helps...jus=
t my feelings...is that most splash guards are taller than the wheelhead=
. this causes your forearm to go into the clay at a slight angle...this =
is especially annoying to me durring centering. i cant quite seem to get=
my arm in the perfect position to keep the base of the clay from moving=
around...so i removed the splash guard and now i have no problem. and a=
s you are doing your pulls it also allows me to get even with the very b=
ase of the clay....i use my pinky and whole hand alot of the time in th=
e first pulls...this somewhat gives it the nice lines of a thrown pot an=
d also performs a collaring motion all in one. i cant do this pull with =
the splash guard in place. again...this is only a suspicion for me. i h=
ave not tested it or anything close to a test. ive just noticed that as =
soon as i lost the splash guard i felt beter and more natural on the whe=
el....which in turn made me a better potter. mybe it will work for you.
on a rebuttle to previous statements...i have never found that trimming =
the buttress of a pot helps at all. ive tried it and noticed no differen=
ce in hieght or beauty of the pot. usually i just ened up with a funny l=
ooking base for those pots...usually ending back up in the clay barrel. =
maybe i am just doing it wrong. i am still learning and would actually l=
ike to hear other peoples ideas on how to do this...id love to add anoth=
er trick to my arsenal for throwing tall. =
so in recap the most important things to me are: dont use bad clay...mak=
e sure it is stiff and not deflocculated (to see if a clay is defloccula=
ted take a ball of clay that you know is fairly dry...hold it in your ha=
nd for a few minutes and just feel it as it slumps...if it is defloccula=
ted it will start to mold itself to your hand...not bad...just a little =
noticably to your hand. good clay shouldnt do this very much at all.)...=
use a hair dryer several times while you throw...they do help...or even =
a fan as the wheel spins...this give a much more even drying, use slip i=
nstead of water, and for me ditch the splash guard. and also...throw sta=
nding up...ive found that helps too..dont know why...it just does.
anyways. best regards and i hope everyones problems somehow get solved. =
i havent been doing this very long...but i have studied it relentlessly =
and this is what i have found to help. =
take care
jason palmer =
boobyagga@juno.com
beaumont, Texas
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