Nancy Marenger on sat 26 nov 05
I'm new on this site, and want to undertake making some sinks. I have a
kiln and a Pacifica wheel. I'm concerned about the amount of warpage I've
experienced in making large bowl shapes, and I'm wondering if you have any
viable solutions. What can I do and still consider making handmade sinks?
pdp1@EARTHLINK.NET on sat 26 nov 05
Hi Nancy,
Well, three things come to mind to make sure of - but certainly better more
experienced advises will come your way, but for now...
Wedge very well and very thoroughly...
Do not permit differential drying...
Fire in some part of the kiln whose flow and heats are the most even for an
object that size, or, protect it in with baffles or muffles which will even
out it's exposure to the Kiln's internal temperature and flow vagueries.
Also...on a dofferent aspect -
Study well the gallery form needed for the Drain to affix so it is flush, so
a standard Drain may be used, and to allow for the shrinkage of the
aperature's diameter to the size it will be when fired, so the Drain fits
well and snug and flush into it's relieved gallery when all is done...
Sounds like fun to me...!
Phil
Las Vegas
----- Original Message -----
From: "Nancy Marenger"
> I'm new on this site, and want to undertake making some sinks. I have a
> kiln and a Pacifica wheel. I'm concerned about the amount of warpage I've
> experienced in making large bowl shapes, and I'm wondering if you have any
> viable solutions. What can I do and still consider making handmade sinks?
>
>
____________________________________________________________________________
__
> Send postings to clayart@lsv.ceramics.org
>
> You may look at the archives for the list or change your subscription
> settings from http://www.ceramics.org/clayart/
>
> Moderator of the list is Mel Jacobson who may be reached at
melpots@pclink.com.
darrell calhoun on sat 26 nov 05
I have struggled with this for a while now. What I have learned through many mistakes is to (1) use a stoneware with a medium ammount of filler (2) I have added five percent granular kyanite before and it really seemed to discourage warping but you will need to recalculate the shrinkage rate of the body (3) I use a hump mold after centering on the wheel, when the mold releases I have 2 of my students flip the mold slowly while I support the bowl. If done with constamt pressure the mold can lift out without distorting the form. (4) Before taking the mold off of the wheel (sorry I forgot) cut the drainhole (calculate the shrinkage to fit the fixture in question-usually I shoot for a 1.5" hole after the glaze firing). (5) Now re-center the bowl by throwing a chuck to sit the bowl in ( Ihave recently started using a flower pot that I attach to my Giffin Grip to sit the bowl in. This works very well with some practice.) (6) After doing this you are ready add and throw your rim,
clean and decorate the inside and very it's important to carve sharper angle for the drain area to make sure all the water exit when draining (7) When the finished bowl is leather-hard flip it over onto a sturdy ware-board cover with a soft towel. (8) Now drape the sink with plastic a let it dry completely upside down. By doing this you are using the clay's weight to discourage warping. I Have also successfully bisque-fired some sinks upside down on top of a bed of medium grog. This is a little risky but fires a very flat rimmed bowl.One more thing to remeber is that as a general rule the bowl's wall thickness must be proportional to it's diameter to depth ratio. Basically if the walls need to be thicker when the bowl's span puts alot stress on the walls. I hardly ever ever go less than 3/4". That may sound thick but I have had little warping lately. I hope this helps. Sorry about the messy grammar I'm in hurry. Good Luck!
Nancy Marenger wrote: I'm new on this site, and want to undertake making some sinks. I have a
kiln and a Pacifica wheel. I'm concerned about the amount of warpage I've
experienced in making large bowl shapes, and I'm wondering if you have any
viable solutions. What can I do and still consider making handmade sinks?
______________________________________________________________________________
Send postings to clayart@lsv.ceramics.org
You may look at the archives for the list or change your subscription
settings from http://www.ceramics.org/clayart/
Moderator of the list is Mel Jacobson who may be reached at melpots@pclink.com.
---------------------------------
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Kathi LeSueur on sat 26 nov 05
Nancy Marenger wrote:
>I'm new on this site, and want to undertake making some sinks. I have a
>kiln and a Pacifica wheel. I'm concerned about the amount of warpage I've
>experienced in making large bowl shapes, and I'm wondering if you have any
>viable solutions. What can I do and still consider making handmade sinks?>>
>
If you want to make sinks to sell to others, the first thing you have to
consider is the vitrification of your clay. Sinks can be considered
sanitary ware and may need to meet absorption standards. Other than
that, I've always thrown sinks upside down. It's easier to control the
clay and I can make a good strong rim. Make them thinker than you would
an average bowl.
Kathi
>
>
>
>
L. P. Skeen on sat 26 nov 05
You need to talk to Linda Blossom; she is the queen of handmade sinks.
L
----- Original Message -----
From: "Nancy Marenger"
> I'm new on this site, and want to undertake making some sinks. I have a
> kiln and a Pacifica wheel. I'm concerned about the amount of warpage I've
> experienced in making large bowl shapes, and I'm wondering if you have any
> viable solutions. What can I do and still consider making handmade sinks?
Michael Wendt on sun 27 nov 05
Ingeborg,
Centering 25 lbs is fairly easy if you remember not to try too hard. I use
the lowest part of my palm and take my time. Also, since the sink is fairly
thick, the clay can be a little softer.
I like smooth clay for sinks to avoid glaze defects so I use a clay I make
called 38 Special because it is only 38% clay and 62% non plastics
(Feldspar, Neph Sye, 125 mesh silica and 200 mesh silica) .
It takes a glaze like chun beautifully and throws easily too.
By all means, get a heavier guitar string. Ernie Ball makes guitar strings
in different diameters. I use 0.009 for my wheel head cut off wire but I use
0.020 or a little heavier for wedging. Get a few heavier wires and try them
too.
Also, if you are snagging the wire, Make a cardboard cover for it and use a
small spring clamp to hold it on. You might even want to decorate the
cardboard with bright colored stickers to make it more visible.
Regards,
Michael Wendt
Wendt Pottery
2729 Clearwater Ave
Lewiston, Idaho 83501
USA
wendtpot@lewiston.com
www.wendtpottery.com
Michael Wendt on sun 27 nov 05
Nancy,
No matter whether you are making large bowls or large sinks, the rules for
preventing warping are the same:
1. ) The clay must be very uniform in moisture before you start to throw.
Wire wedging works best for this step.
2. ) The centering and opening must be the very best since an uneven wall
shrinks unevenly and warps.
3. ) Dry the sink rim down under a sheet of cloth in a damp box to assure no
drafts cause it to warp.
4.) While firing, be sure the sink is :
a) sitting on a smooth, level shelf with alumina bedding
b) centered in the kiln
c) saggared to slower heating and cooling.
I charge $250-350 per sink and sell plenty. The yield is nearly 100% over
the last 32 years using these steps.
Yield (survival rate) makes or breaks you.
One of our mottos here is:
Do all the steps right the first time or do it over.
Regards,
Michael Wendt
Wendt Pottery
2729 Clearwater Ave
Lewiston, Idaho 83501
USA
wendtpot@lewiston.com
www.wendtpottery.com
Ingeborg Foco on sun 27 nov 05
Michael,
Since you make a lot of sinks, could you tell me what thickness you throw
your sinks. It's a timely discussion for me as all of a sudden I need to
make two!
Thank you,
Ingeborg
the Potter's Workshop & Gallery
P.O. Box 510
3058 Stringfellow Road
St. James City, Florida 33956
239-283-2775
Michael Wendt on sun 27 nov 05
Ingeborg,
The 20" w x 7" tall wet sink I make finishes about 18" w x 6" h at cone 10
and starts out as 25 lbs of clay. The wall is at least 1/2" and the rim is
3/4" thick. Once dry, I saggar them and candle overnight to avoid steam
explosions. I haven't blown one up since I started doing this over 25 years
ago... tap, tap, tap (me knocking on wood, you can never get too big headed
around clay or it slaps you back down to remind you, it is a partnership,
not a master-slave relationship) ;-)
Regards,
Michael Wendt
Wendt Pottery
2729 Clearwater Ave
Lewiston, Idaho 83501
USA
wendtpot@lewiston.com
www.wendtpottery.com
pdp1@EARTHLINK.NET on sun 27 nov 05
Hi Michael, Ingeborg, all...
Nice mentions...
Now, so far I seem to be the only one to have elaborated a little on the
'drain' and it's finesse.
Probably there are differing ways to deal with how the physical Metal Drain
piece shall sit, or what kind it shall be.
My own thought, having seen some 'bad' Sinks, and, some 'good' ones, is that
a correct anticipation of the diamater of the drain pipe itself, and, of
course, it's flange, and for it's flange to end up recessed to be flush,
which will show in the Sink's bottom when all is done...is important.
For the flange to be recessed and to have a thin fibre or rubber washer
under it, a stait, stop or 'gallery' needs to be there, and it must not be
too shallow or the flange will sit proud and embarass the maker or owner of
the Sink.
Anyway, maybe some better elaborations than mine could get discussed so that
others who are starting to make Sinks may find some good tips on that part
of the design.
Also, some people like Sinks which have an overflow feature, so if a stopper
is in place and the tap is left running, the Sink will drain from an
aperature of some kind which is just shy of the rim.
This of course adds to the complexity of the post-thrown tasks, to make and
fit such a 'tunnel' along one side for that feature to be there and to
function well...it also requires a different or longer 'end' at the Drain
portion, to recieve the overflow 'tunnel'...below the drain proper.
Anyway, since these aspects had not been mentioned so far as I noticed, I
just wanted to bring them up....
Best wishes...
Phil
Las Vegas
----- Original Message -----
From: "Michael Wendt"
> Ingeborg,
> The 20" w x 7" tall wet sink I make finishes about 18" w x 6" h at cone
10
> and starts out as 25 lbs of clay. The wall is at least 1/2" and the rim is
> 3/4" thick. Once dry, I saggar them and candle overnight to avoid steam
> explosions. I haven't blown one up since I started doing this over 25
years
> ago... tap, tap, tap (me knocking on wood, you can never get too big
headed
> around clay or it slaps you back down to remind you, it is a partnership,
> not a master-slave relationship) ;-)
> Regards,
> Michael Wendt
Ingeborg Foco on sun 27 nov 05
Michael,
Ouch my poor elbows, 25 lbs of clay.
I have been using your laminating/wedging system but have broken the guitar
string lets see, three times now I think. Right now it is broken! The guy
at the guitar shop must think I am a real lousy player. I think I need to
get something heavier that will hold up to my abuse. I usually don't wear
my glasses in the studio and end walking by the wire with something in my
hands and without seeing the wire swing something into it...twang, broken
again:).
Would you add a lot of grog to normal Cone 10 clay or is the laminating
sufficient?
Thanks for the info Michael.
Sincerely,
Ingeborg
the Potter's Workshop & Gallery
P.O. Box 510
3058 Stringfellow Road
St. James City, Florida 33956
239-283-2775
> Ingeborg,
> The 20" w x 7" tall wet sink I make finishes about 18" w x 6" h at cone
10
> and starts out as 25 lbs of clay. The wall is at least 1/2" and the rim is
> 3/4" thick.
Elizabeth Priddy on sun 27 nov 05
Have the guitar guy sell you a used bass string.
Very thick, extremely hard to break.
EP
lucky to have guitar strings galore round here.
--- Ingeborg Foco wrote:
> Michael,
>
> Ouch my poor elbows, 25 lbs of clay.
>
> I have been using your laminating/wedging system but have broken the
> guitar
> string lets see, three times now I think. Right now it is broken!
> The guy
> at the guitar shop must think I am a real lousy player. I think I
> need to
> get something heavier that will hold up to my abuse. I usually don't
> wear
> my glasses in the studio and end walking by the wire with something
> in my
> hands and without seeing the wire swing something into it...twang,
> broken
> again:).
>
> Would you add a lot of grog to normal Cone 10 clay or is the
> laminating
> sufficient?
>
> Thanks for the info Michael.
>
> Sincerely,
> Ingeborg
>
> the Potter's Workshop & Gallery
> P.O. Box 510
> 3058 Stringfellow Road
> St. James City, Florida 33956
>
> 239-283-2775
>
>
> > Ingeborg,
> > The 20" w x 7" tall wet sink I make finishes about 18" w x 6" h at
> cone
> 10
> > and starts out as 25 lbs of clay. The wall is at least 1/2" and the
> rim is
> > 3/4" thick.
>
>
______________________________________________________________________________
> Send postings to clayart@lsv.ceramics.org
>
> You may look at the archives for the list or change your subscription
> settings from http://www.ceramics.org/clayart/
>
> Moderator of the list is Mel Jacobson who may be reached at
> melpots@pclink.com.
>
Elizabeth Priddy
Beaufort, NC - USA
http://www.elizabethpriddy.com
__________________________________
Yahoo! Music Unlimited
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pdp1@EARTHLINK.NET on mon 28 nov 05
Hi Ingeborg,
Conventional braided-strand 'Picture Hanging Wire' may work well...
A single strand 'Guitar String', if Carbon Steel ( not Cat Gut or Nylon or
whatever they use now, ) will tend to work harden and become brittle and
break at some point if bent around repeatedly, far sooner than thinner
strands which are braided to stay together snugly as-a-team...
But if you do want a realy stout 'wire', get a lower register 'String' from
a Concert Grand Piano...
(Just kidding, it would be way WAY too thick and stout...Lol...)
Phil
el ve
> --- Ingeborg Foco wrote:
>
> > Michael,
> >
> > Ouch my poor elbows, 25 lbs of clay.
> >
> > I have been using your laminating/wedging system but have broken the
> > guitar
> > string lets see, three times now I think. Right now it is broken!
> > The guy
> > at the guitar shop must think I am a real lousy player. I think I
> > need to
> > get something heavier that will hold up to my abuse.
<<<<<<<<>>>>>>>>>
Michael Wendt on mon 28 nov 05
Phil,
You raise a good point. One way to model this problem is with "mock-up"
bowls which are small scale sinks made of the same clay and glaze. When a
customer wants a new, untested glaze pattern, I start with modest size bowls
as samples and thus gives them the chance to see the finish and choose from
what is possible with your process. Have the customer bring in the actual
drain pieces they plan to install and make sure the sink fits these properly
with the correct slopes and hole diameters.
There is no reason you can't tool the bottom hole in a small trial bowl and
install the drain features to permit you to test your drain characteristics
and give you the needed scaling factor for the hole.
Scaling factors are some number greater than one that you multiply the
desired finished size by. If I want a 10" bowl, I need to "scale" it this
way:
10" X 1.13 = 11.3". I got this by dividing countless finished bowl diameters
into their originally measured wet size and writing it down.
I use plumbers putty under the internal ring and test the design with water.
Regards,
Michael Wendt
Wendt Pottery
2729 Clearwater Ave
Lewiston, Idaho 83501
USA
wendtpot@lewiston.com
www.wendtpottery.com
Phil wrote:
My own thought, having seen some 'bad' Sinks, and, some 'good' ones, is that
a correct anticipation of the diameter of the drain pipe itself, and, of
course, it's flange, and for it's flange to end up recessed to be flush,
which will show in the Sink's bottom when all is done...is important.
For the flange to be recessed and to have a thin fiber or rubber washer
under it, a stop or 'gallery' needs to be there, and it must not be
too shallow or the flange will sit proud and embarrass the maker or owner of
the Sink.
Anyway, maybe some better elaborations than mine could get discussed so that
others who are starting to make Sinks may find some good tips on that part
of the design.
Also, some people like Sinks which have an overflow feature, so if a stopper
is in place and the tap is left running, the Sink will drain from an
aperture of some kind which is just shy of the rim.
This of course adds to the complexity of the post-thrown tasks, to make and
fit such a 'tunnel' along one side for that feature to be there and to
function well...it also requires a different or longer 'end' at the Drain
portion, to receive the overflow 'tunnel'...below the drain proper.
Anyway, since these aspects had not been mentioned so far as I noticed, I
just wanted to bring them up....
Best wishes...
Phil
Las Vegas
Bonnie Staffel on mon 28 nov 05
Hi Clayarters,
When I was about to make sinks, I went to the hardware store and bought
the metal drain part so that I would have those measurements. Then I
threw the bottom maybe three inches of the bowl and the clay tube that
is to fit the metal parts. I measured at every point during the final
throwing, bisque and stoneware temperature. I keep that piece with the
measurements written on them so I can duplicate.
After some sinks were installed, I checked with one customer's sink as
he said it was crazing. Well, I had never had any crazing problem with
my base glaze. On looking at the sink I saw the crazing was in one spot
about 6 inches in diameter. He said he had a super hot water appliance
for his shaving and that shot right at the spot on the sink.
Another post installation problem is that usually plumbers make the
drain hole in the wall at a certain height without considering the depth
of the hand made sink. I had made a rather deep bowl suitable for hand
washing so when the plumber installed and connected the parts, he didn't
alter the drain plug stick that opens and closes the drain. It is one
tight fitting. This one is in my daughter's powder room. I have tried
to adjust these things, but they are hard to manipulate on one's knees
and under the counter. But to review this, my own sink is a standard
one and that cover sure doesn't open very high either. Maybe I had a
novice plumber. You know they don't usually send their top plumbers to
the construction site much any more. They have the apprentices do the
work. Just in my circle of friends alone, I have seen some gross errors
in the installation of the plumbing. However, when it comes to
electrical work, I have the best and he personally installs the wiring
in the millionaire mansions that are popping up like puff balls in this
area.
I would suggest that you go to where they sell sinks of all kinds, below
and above counter sinks and take measurements, and look them over
carefully. I also looked at a Kohler catalog of hand decorated sinks so
that I could compare my prices with those, since mine are hand decorated
too.
Warm regards,
Bonnie Staffel
http://webpages.charter.net/bstaffel/
DVD Throwing with Coils and Slabs
DVD Beginning Processes
Charter Member Potters Council
Bonnie Staffel on mon 28 nov 05
Hi Clayarters,
I throw my sinks upside down using my Coil and Slab method. Two easy
coils and I have the sink made. No struggle, no muscles needed. If I
see I need a little more clay at the top to make the tube form, I then
add a small coil and continue throwing. Note my DVD that shows how to
throw with a coil.
Regards, Bonnie Staffel
http://webpages.charter.net/bstaffel/
DVD Throwing with Coils and Slabs
DVD Beginning Processes
Charter Member Potters Council
Nancy Marenger on wed 30 nov 05
On Sat, 26 Nov 2005 17:41:12 -0800, darrell calhoun
wrote:
>I have struggled with this for a while now. What I have learned through
many mistakes is to (1) use a stoneware with a medium ammount of filler
(2) I have added five percent granular kyanite before and it really
seemed to discourage warping but you will need to recalculate the
shrinkage rate of the body (3) I use a hump mold after centering on the
wheel, when the mold releases I have 2 of my students flip the mold slowly
while I support the bowl. If done with constamt pressure the mold can
lift out without distorting the form. (4) Before taking the mold off of
the wheel (sorry I forgot) cut the drainhole (calculate the shrinkage to
fit the fixture in question-usually I shoot for a 1.5" hole after the
glaze firing). (5) Now re-center the bowl by throwing a chuck to sit the
bowl in ( Ihave recently started using a flower pot that I attach to my
Giffin Grip to sit the bowl in. This works very well with some
practice.) (6) After doing this you are ready add and throw your rim,
> clean and decorate the inside and very it's important to carve sharper
angle for the drain area to make sure all the water exit when draining
(7) When the finished bowl is leather-hard flip it over onto a sturdy ware-
board cover with a soft towel. (8) Now drape the sink with plastic a let
it dry completely upside down. By doing this you are using the clay's
weight to discourage warping. I Have also successfully bisque-fired some
sinks upside down on top of a bed of medium grog. This is a little risky
but fires a very flat rimmed bowl.One more thing to remeber is that as a
general rule the bowl's wall thickness must be proportional to it's
diameter to depth ratio. Basically if the walls need to be thicker when
the bowl's span puts alot stress on the walls. I hardly ever ever go less
than 3/4". That may sound thick but I have had little warping lately. I
hope this helps. Sorry about the messy grammar I'm in hurry. Good Luck!
>
>Nancy Marenger wrote: I'm new on this site, and
want to undertake making some sinks. I have a
>kiln and a Pacifica wheel. I'm concerned about the amount of warpage I've
>experienced in making large bowl shapes, and I'm wondering if you have any
>viable solutions. What can I do and still consider making handmade sinks?
>
>__________________________________________________________________________
____
>Send postings to clayart@lsv.ceramics.org
>
>You may look at the archives for the list or change your subscription
>settings from http://www.ceramics.org/clayart/
>
>Moderator of the list is Mel Jacobson who may be reached at
melpots@pclink.com.
>
>
>
>
>---------------------------------
> Yahoo! Music Unlimited - Access over 1 million songs. Try it free.
>
>__________________________________________________________________________
____
>Send postings to clayart@lsv.ceramics.org
>
>You may look at the archives for the list or change your subscription
>settings from http://www.ceramics.org/clayart/
>
>Moderator of the list is Mel Jacobson who may be reached at
melpots@pclink.com.
Darryl,
Thank-you very much for the great advice. It sounds like you've made a
few,and know much from experience. What clay would you suggest if I use
cone 6 glazes? I've never used a hump mold. Do you roll out the clay and
lay it on the hump or what? I feel stupid asking some of these questions,
but I've only ever delt with a wheel and basically handbuilding. Someone
just informed me about how to throw upside down, and I'm totally amazed
and excited about the idea. What a newby!!!!!I guess this is what this
forum is for.
I'm keeping the info you gave me on file for future reference. Thanks
Nancy
Kathi LeSueur on wed 30 nov 05
Nancy Marenger wrote:
>Kathi,
>Thanks for replying. What clay would you suggest using for sinks? I've
>heard porcelain being used, but I find working with it difficult. Also,
>pardon my ignorance, but I have tried every way imaginable in my mind of
>how you can throw a bowl upside down9many are really funny!), but I can
>only think of using a hump mold that way. Did you mean you use a hump
>mold? If so, how do you combine it with a wheel? Oh boy, it's been a while
>since I've had my studio.........Thanks for your help.
>Nancy
>
>______________________________________________________________________________
>
>
>
I use a commercial body (Balcones) that I get from Armadillo clay in
Austin, TX. I usually add some grog to it when I wedge it.
To throw a sink upside down, center the clay as usual. Open the clay
right down to the bat and bring it out as wide as you want the top of
the sink to be. Then pull the clay up and in just as you would if you
were making the top half of a bottle form. I always make a rim right at
the beginning of pulling up the clay. Get the curve you want on the bowl
before you do the final collaring down of the neck.
My sinks are about 1/2 inch thick. When they are leather hard I turn
them over and trim the rim, the opening for the drain, and refine the
inside of the bowl. I have a chuck that I made specifically to set sinks
in for trimming. It's really not that hard. Takes lots of clay. If
centering is a problem, use the Mel Jacobsen method. Center about five
pounds of clay. Clean off slurry with a rib. Put another five pounds on
the centered clay. Center that. Continue until you have the amount of
clay you want centered. I use this method now with all of my big pieces.
Good luck,
Kathi
Nancy Marenger on wed 30 nov 05
Bonnie,
I like your approach. I went to your wb site but was unable to see where I
could get/order your DVD. What did I overlook?
On Mon, 28 Nov 2005 14:44:46 -0500, Bonnie Staffel
wrote:
>Hi Clayarters,
>
>I throw my sinks upside down using my Coil and Slab method. Two easy
>coils and I have the sink made. No struggle, no muscles needed. If I
>see I need a little more clay at the top to make the tube form, I then
>add a small coil and continue throwing. Note my DVD that shows how to
>throw with a coil.
>
>Regards, Bonnie Staffel
>
>http://webpages.charter.net/bstaffel/
>DVD Throwing with Coils and Slabs
>DVD Beginning Processes
>Charter Member Potters Council
>
>__________________________________________________________________________
____
>Send postings to clayart@lsv.ceramics.org
>
>You may look at the archives for the list or change your subscription
>settings from http://www.ceramics.org/clayart/
>
>Moderator of the list is Mel Jacobson who may be reached at
melpots@pclink.com.
Nancy Marenger on wed 30 nov 05
Kathi,
Thanks for replying. What clay would you suggest using for sinks? I've
heard porcelain being used, but I find working with it difficult. Also,
pardon my ignorance, but I have tried every way imaginable in my mind of
how you can throw a bowl upside down9many are really funny!), but I can
only think of using a hump mold that way. Did you mean you use a hump
mold? If so, how do you combine it with a wheel? Oh boy, it's been a while
since I've had my studio.........Thanks for your help.
Nancy
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