Clay Extrude Use

7/30/2019 Clay Extrude Use

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www.ceramicartsdaily.org | Copyright 2010, Ceramic Publications Company | Clay Extruder Users Guide | i

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clay extruderusers guide

tips, techniques, and projects

for getting the most outof your ceramic extruder

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www.ceramicartsdaily.org | Copyright 2010, Ceramic Publications Company | Clay Extruder Users Guide | 1

20 Tips That Will Increase YourExtruder Experience

by Daryl BairdHere are 20 tips that are sure to improve your success with extruders no matter what. From advice onhow to prepare and load the clay to techniques or keeping extrusions straight and ree rom faws, thesetips are sure to help.

Credit Card Clay Extruder Diesby Daryl BairdNothing helps you learn aster than taking on a simple, yet challenging project. Daryl shows you how totake your old credit cards and make simple extruder dies, then shows you how to make ceramic house

numbers with your extrusions.

Twisted Lotion Dispensersby David HendleyExtruders can do things not possible with the wheel or handbuilding and heres a good example. Daviddemonstrates how to make his unique lotion bottles. The trick? Careully twisting the clay extrusion as itexits the extruder.

Rope-top Bucketby David HendleyVeteran extruder user David Hendley oers another project thats really simple to do although it lookscomplicated. He makes a clay rope decoration or his wheel-thrown buckets and adds a wire bale or ahandle. To make rope with a ceramic extruder, all you need is a simple die with three holes drilled into it.Youll want to make many sizes because the rope is easy to create once you have the extruder die.

Clay Extruder Users Guide

Tips, Techniques, and Projects for

Getting the Most Out of Your Ceramic Extruder

The ceramic extruder is now commonly seen in a majority o schools and community ceramic centers as well as thou-sands o private studios. This versatile tool was relatively unknown back in the 1970s, but thats history. Because o its

versatility, the clay extruder has embedded itsel as an indispensable tool or thousands o potters and ceramic artists.


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1Assemble it correctly. Make sure your extruder isassembled correctly, according to the manuacturersinstructions. I you bought a used or custom-madeextruder, ask the person who sold it to you to cover theoperation basics, i possible.

2Use moist clay that has been wedged well.This cant beoverstated. Just about any clay can be pushed throughan extruder, but the results will vary enormously, depend-ing on the characteristics o each. Clearly some clay bod-ies are better suited to extruder work than others. As ageneral rule, any clay in a condition that is well suited oruse on a potters wheel will work well in your extruder.This is not to say that you cant use resh clay right out othe bag. But i it has been around awhile and it seems alittle sti, it will be more dicult to use in your extruder.You shouldnt have to exert superhuman orce to get theclay to move through the die.

3Practice, practice, and more practice. Just about everytool or instrument requires some practice i youre go-ing to master it. I youre new to extruding, give yourseland the extruder a chance.

4Working alone? Use the chest press method. Underllthe barrel so the handle is lower and closer to the bar-rel when you start. Now, standing directly in ront o theextruder, square up your stance and press the handle withthe center o your chest. This rees both o your hands toguide the clay as it extrudes.

20 Tips to Increase YourExtruder Experience

by Daryl Baird

5Cut off the first few inches. The rst part o an extru-sion never seems to come out straight. Cut it osquarely, then nish your extrusion. I youre making ahollow extrusion, you can help it to come out straighterby pressing your fattened hand with slight upward pres-sure against the bottom o the extrusion as you pull on

the handle with your other hand.

6Make a one-handed cut-off wire.Mount one end o acutting wire or a piece o shing line on the wall nextto the bottom edge o the extruder. Let the other endhang ree. Ater making an extrusion, support it rom thebottom with one hand, then grasp the ree end o yourcutting wire and draw it through the clay along the bot-tom o your extruder.

7Center the die.I you want straight extrusions, theopening in the die has to be centered in the barreldirectly under the plunger. In a hollow-orm die, the internal die pieces have to be centered relative to the perimeterwalls o the die.

8Install dies off-center for curved extrusions. This wontwork with some extruders because their dies are xedin one place, but i you can move yours rom side to sideor ront to back, you might do some experimenting.

9Use a padded miter box. Use a padded miter box tomake clean 90 cuts on the ends o your hollow extru-sions. Wait until the extrusion has rmed up to a sot


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leather-hard, then lay it in the miter box. Use a cuttingwire to cut through the clay using the notches as a guide.Line the bottom o your miter box with a piece o oampadding, which allows you to push your cutting wire allthe way through the clay.

10Slice open a cylinder to make a slab. Cylinders madewith an extruder can be cut down one side andlaid fat to make a slab. I you have a cylinder die with adiameter o 3 inches, it will yield a slab approximately 9inches wide. Recalling your high school geometry, the cir-cumerence o a circle equals the diameter times 3.14. Tominimize warping, turn the slab over, curled edge down,beore rolling it fat.

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Use paddles to help square up things. Square extru-sions can be straightened by using two one-by-

our-inch boards, each about a oot long. I the insidewall width is smaller than three inches, cut anotherboard to t inside the extrusion. With your extrusionresting on the table, slide the board inside and apply lightdownward pressure to fatten the extrusion wall. Holdone o the other boards in each hand and straighten theextrusion rom the outside by squeezing the extrusionbetween the boards. Do this on all sides until the extru-sion is square.

12True up cylinders from the inside out. Truing upcylindrical extrusions can be a little tougher.Look or a tube that ts snugly inside the extrusion aterthe clay has been allowed to rm up some. I necessary,wrap a tube with some paper to get the correct diameterand secure it with tape. Slide the tube into the extrusionwith a twisting motion. I youre making a vessel romthe tube, do the straightening beore adding the bottom.Otherwise air will get trapped, making it dicult toremove the tube.

13Save those inner tubes. I the clay leaks outside yourscrew- or twist-on type die holder, you can makea gasket that rests on the die rom an old piece o car

inner tube, or rom gasket material you can buy at a carparts store.

14Unlike potters wheels, which seem to thrive onneglect, extruders need regular cleaning to do theirjob eciently. The cleaning requirement can be one o thebiggest turnos to extruder use, but it doesnt have to bethe drudgery some make it.

15Protect your dies and extend their lives. Spray a light,even coat o a silicone spray like WD-40, or anonstick pan coating like Pam, over the parts that will bein contact with clay beore loading the barrel. Use it spar-ingly each time youre preparing to use your extruder.

16Remove clay before it dries. Do not let clay dry onthe plunger plate or in the barrel. Dry clay is dou-bly hard to remove, and pushing the plunger through abarrel encrusted with dry clay can lead to excess wear onthe plunger plate. Dried-on clay should be sotened witha spray o plain water or a soap solution. It can then bescraped ree with a rubber rib.

17Use cloth scraps to clean your barrel. Placing a pieceo dampened denim cloth over the plunger andpushing it through the barrel helps clean the inside walls.

I this doesnt move well through the barrel, try a lighter-weight material.

18Apply more leverage for small-opening dies. I yourextruder comes equipped with a short handle and alonger handle, the longer handle will give you more lever-age when trying to push clay through a die with a smallopening. Having to resort to extra leverage may, howeverindicate the need or moister clay. Clay that may seemtoo moist to handle at rst may prove to be ideal whensubjected to the extra compression o passing through asmall die opening.

19Make a gang die to make coils more easily. Extrud-ing a single, small-diameter coil can be very di-cult i your extruder has a large barrel. Too much orceis required to push the clay through the small opening.To make the job easier, use a our-place coil die, which isreerred to as a gang die.

20Extrude some test tubes. Small-diameter, hol-low tubes cut into short lengths make excellentpieces or testing glazes. Any o the common orms willwork, but the hexagonal tube is especially useul. It can

be set on end or laid on its side in the kiln to test glazefow characteristics. Draw a pattern o lines down oneside with a ork or a serrated rib. These will help you seehow a glaze breaks over edges. Scratch code letters andnumbers into the leather-hard test tube or identication.Hang these tubes on the wall or tie them to the handle oyour glaze bucket with a piece o wire.


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by Daryl Baird

Credit Card Extruder Dies

For several years, I hadthe opportunity to workalongside Jim Robison onthe commercial exhibit

foor at the annual National Coun-cil on Education or the CeramicArts (NCECA) conerence. Weworked the booth like a couple otraveling medicine men. First, Jimwould draw the townsolk inby demonstrating his considerable

skill with a slab roller and an ex-truder, then I would sell them onthe idea o personally owning oneor both o these wonderul pieceso equipment.

I always enjoyed seeing how Jimcould easily seize the attention opassers-by while he added beauti-ul touches to the vases and plat-ters he built in just minutes, usingsimple tools he ound in kitchenshops and paint stores. A pie crust

ventilator made subtle scored lines

TIPClean the credit card with soap

and water beore starting to

draw on it.

A ew simple tools are needed to create dies.

in the clay while a tiny paint rollerand a piece o lace trim gave itexquisite texture.

In addition to demonstrating atNCECA, Jim conducts workshops

in Europe and North America.Among the most intriguing itemshe takes with him are the extruderdies he has ashioned rom creditcards, membership cards, and co-ee cards.

Recently, a riend asked meto make an address sign or hernew home. As a devoted extrud-ist, I wanted to make the sign,at least partly, with my avoritestudio tool. None o the stock diesI had on hand seemed suitable,so I decided to make the shapes Ineeded using Jims credit card dieconstruction techniques.

Making a DieYoull need a ew simple tools ormaking a credit card extruder die(above)a no. 2 pencil, an indel-


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ible marker with a ne point, a

Dremel tool and assorted bits, anX-Acto knie and several No. 11blades, emory cloth or 150-gritsandpaper, rubbing alcohol, and asmall rag. Saety glasses are essen-tial when using the Dremel tool.Optional tools include a hand drilland bits, a scroll saw, a jewelerssaw, and a small vise.

To begin, use a No. 2 pencilwith a good eraser to lay out theshape o the die opening. Dull the

nish o the card with ne sand-paper i the pencil marks are toolight. Go over the pencil drawingwith a ne-point, indelible marker,like a Sharpie (fgure 1). I you

make a mistake, these lines can be

removed by wiping the card with arag dipped in rubbing alcohol.

To cut out the shape youvedrawn, a hand-held rotary tool,like the type made by Dremel,works ast (fgure 2) and is airlyeasy to control. These come witha variety o drill bits, along withgrinding and sanding bits thatcan be used to rene the shape othe opening. In addition to us-ing a Dremel tool, I tried cutting

out the die shapes with a scrollsaw. It worked well, but settingup the saw or this was tediousand time-consuming. I also gave acoping saw and a jewelers saw a

Cut out the opening, working inside the line.Outline your design rst in pencil, then use a marker.

1 2

TIPAs you clean up the die

opening, hold the credit

card die up to a bright

light. This makes it eas-ier to gauge where more

trimming needs to be

done.

Trim burrs with an X-Acto knie. Sand the die smooth.

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try. Even with a ne-toothed blade

installed, the coping saw was nextto impossible to use. The jewelerssaw cut more smoothly but it wasslower than using a Dremel tool.

Once the opening has been cut

out with the Dremel tool, itll berough, so youll need to clean itup. I like using an X-Acto kniewith a No. 11 blade to clean upthe opening and square-up thecorners (fgure 3). The bladesdull quickly when cutting plastic.

Have several on hand and changeblades oten.

Once the die shape is done,

use a small piece o sandpaper oremory cloth to clean o any burrs(fgure 4). I used a narrow stripcut rom a oam-backed sandingpad because it ts the contoursand corners.

Using a DieCredit card extruder dies are best

suited or use with extruders thathave a 3 to 4-inch barrel. Donttry to use credit card dies in large-barreled extruders because thesetypes o extruders will exert too

much pressure on the die, and

cause it to crack. For the samereason, youll achieve the bestresults by using only a two orthree pound charge o very sot,well-wedged clay in the extruderto minimize the stress placed onthe die. Place the card on an ex-truder die with a hole somewhatlarger than the hole you just cut.Im using a North Star standardextruder and the outer part o asmall hollow die makes an ideal

mounting plate or the credit carddie. Looking rom the underside,make sure the die is centered(fgure 5).

Hold the die in place and turnit ace up. Use small wads o sotclay to anchor the credit cardto the mounting plate (fgure 6).Then, attach the die to the ex-truder barrel and load the chargeo clay into the extruder barrelcareully so the credit card does

not become misaligned.Evaluate the rst extrusion. I

areas need to be rened, its easyto go back and give the shape alittle tune up.

Place the die on an extruder die to check the t. Attach the die with clay wads to a standardextruder die.

5 6


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TIP

When working onlarge, fat projects,

use a sheet o drywall

as a work surace to

minimize warping.

Be sure to cover any

exposed plaster with

Duct tape or similar.

Street Address ProjectTo illustrate the use o these dies, I made a street address sign or my home. I rolled a large slab

o clay that was just under a hal-inch thick and cut out the oval shape using a plastic serving

platter as a template.

So ar, I have three credit card dies in my collection. I used the extrusion rom my bull nose

shaped die to create a decorative rim or the edge o the clay slab. The height o the notch in the

extrusion matches the thickness o the clay slab. Make the bull nose extrusion long enough tocover the entire circumerence o the slab and attach it as soon as its extruded. Spray the slab

beore attaching the rim and use even pressure all the way around the piece to bond the trim to

the slab. No scoring or slip is necessary.

I used a T-shaped die to make the numbers or the sign. The die is 1 inch wide by inch high.

The T prole is easy to shape while also oering a large surace area on the underside, ensuring

a strong bond between the extruded shape and the slab.

Make extrusions o several lengths and shape the numbers on a piece o drywall. Draw the

outline o the numbers or letters you want directly onto the drywall, and ollow these lines as

you lay out the extrusions. I the numbers dont look quite right ater the rst attempts, you can

go back and bend them more.

Keep the extrusions moist as you work. I youre assembling a shape rom several extrudedpieces, like the number 4 or example, take care to join the pieces thoroughly. This is where youll

need to score well and apply slip to the joints beore attaching the parts.

Spray the oval slab with a mist o water and lightly place the numbers on the surace. When

each one is properly positioned, repeatedly apply light, even pressure until the numbers are rm-

ly in place. It isnt necessary to distort the shape o the extrusion to achieve good attachment.

Securely wrap the sign in plastic and allow it to rest on the drywall sheet or two or three

days. Aterwards, slide the sign onto a resh piece o drywall and lightly cover it with plastic. This

will help it dry evenly.

Three credit card dies with distinctlycut shapes in each one.

Slab should match the thickness othe notch on the bull nose extrusion.

A T-shaped extruder die is used orthe numbers, which are assembledon drywall.

Address sign, 18 inches long, LagunaSpeckled Bu clay glazed with La-gunas Fern Mist, red to cone 5.


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by David Hendley

Twisted LotionDispensers

Ihave been using extrudersin my clay work since 1974,ater I built my rst extrud-er and made my rst dies. I

immediately saw the potentialor making new orms throughextruding, and Ive always hadan extruder in my studio that Iuse on a regular basis. O all thepieces I make, the extruder is usedor about two-thirds o themtoproduce either the main orm itselor an added element or a wheel-thrown vessel. Even my pulledhandles start out as extrusions.

Producing work with an extrud-er seems like it would enable youto make dozens o items quickly,but just the opposite is oten true.

Because o all the measuring, cut-ting, and joining, an extruded potcan require more time to makethan a similar, thrown pot, but orsome orms, extruding is the mostexpedient way to go.

As or the dies, manuacturers

oer many congurations; howev-er, i you have more than a passinginterest in using an extruder, Idsuggest making your own. Design-ing and making the die is part othe creative process and requiresthinking rom a dierent perspec-tive since its the negative spaceo the die that produces the orm.With practice, youll soon be ableto shit your spatial thinking towhere you can easily picture the

Three nished lotion dispensers, 7 in. (18 cm) in height, handbuilt usingextruded parts, with added eet o unglazed dark brown clay and multicoloredslip-glazes. Pump dispensers added ater glaze ring.


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three-dimensional piece youll get

rom the shape outline cut into

a two-dimensional die, and vice

versa. In act, ater spending alot o time and thought designing

dies, I oten look at everyday ob-

jects and mentally picture what the

die needed to make them might

look like.

Making a LotionDispenserThe orm or the lotion dispenseris made with a two-part die that

produces a 2 inch square tube.

Hollow square tubes are among

the most common shapes ex-

truded, but twisting the extrusion

Twist the extrusion as it exitsthe extruder.

Use a piece o monolament shingline to cut the extrusion.

1 2

Allow extrusions to set up. Turnover ater an hour.

When leather hard, cut extrusionsto length.

Brush on underglazes or vitreousengobes i desired.

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gives a sense o movement to thenished pot.

Lotion dispenser pumps, avail-able rom most ceramic supplystores, come in a variety o stylesand colors. Youll need to pur-chase those beore you attemptthis project so that you can makeappropriate design and color

choices. The collars need to beattached with adhesive ater theglaze ringcheck with your sup-plier or the best combination.

To make the lotion dispenser,load the die into the extruderand ll the extruder barrel with

clay. To minimize air bubbles inthe extrusion, shape the clay soit slides easily yet snugly downthe barrel. Pull down on the levero the extruder with one handwhile twisting the clay as it exitsthe extruder with the other hand(fgure 1). To keep a hollow ormrom collapsing in on itsel as it is

twisted, keep your hand right be-low the die, twisting the clay justas it exits the extruder, and moveyour hand back up as every inchor so o clay comes out. Any aintthumb indentations let on the clayrom the twisting process will not

Round corners and smoothedges o squares.

Cut arches into the top and bottomo the orm.

Trim the bottom slab fush withthe sides.

Cut a 1-inch hole in the top

or the pump.

Use a tool to compress and bevel

the seam.

Roll the top back and orth to com-

press the join.

6 7 8

9 10 11


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be perceptible in the nished piece.While this process eels awkwardat rst, and takes some practiceas well as a wide reach, I have notrouble doing the job by mysel.You may want to have an assistantslowly pull the handle while youpractice the rst ew times. It alsotakes some practice to get a eelor how much pressure is requiredto twist the clay as it comes romthe extruder. Not much pressure isrequired, and most beginners twisttoo much rather than too little.

When you have a long enough

extrusion, cut it loose with a pieceo monolament shing line. Wrapthe shing line around the extru-sion, and allow one end o the lineto dig into the clay, which holds itin place. Use one hand to pull theother end o the line through theclay while the other hand sup-ports the extrusion as it is cut loose(fgure 2).

I always make at least 10 or 12dispensers at a time because o the

signicant set-up and clean-up timewhen extruding through a two-parthollow die. Twisted extrusionsare cut o in 18-to-20 inch longsections and set aside to rm upon a table (fgure 3). In averageweather, I allow the sections to dryor about an hour and then fipand allow to dry or another hour.Measure each extrusion and divideit into three 6 to 7 inch long pieces.Use a ettling knie to cut each

extrusion (fgure 4).For my glazing technique, I apply

slip glazes to the sections o twistedsquare extrusions beore addingthe tops and bottoms (fgure 5).Allow the painted suraces to dry

or several hours beore handlingand continuing with construction.(Ater bisque ring, I glaze the topand insides o the dispensers.)

Once the slip glaze is dry, rollout a slab or the tops and bot-toms o the dispensers. The slabshould be slightly thicker than thewalls o the extrusion. Cut theslab into 2-inch squares, thenround and smooth the edges andcorners o each square (fgure 6).Roll each square again to make itslightly thinner and wider (about2 inches square). I roll past the

edges to create a soter and slightlywavy edge.Next, cut raised arches into the

top end o the extruded section(fgure 7). On the bottom o thepot, cut the arch so the our cor-ners become the eet o the piece.Score and slip the bottom edges,attach the bottom slab and trimthe edges fush with a cheese sliceror ettling knie (fgure 8). Roll thehandle o a ettling knie along the

edges o the bottom at a 45 angleto reinorce the joint and bevel thebottom slab (fgure 9).

Add the top slab but dont trimit, leave the overhang as a designelement. Roll the top back andorth on the table to secure thejoin (fgure 10), allow to dry orabout an hour, then cover withplastic and leave overnight toequalize the moisture.

On the ollowing day, use a

piece o 1-inch tubing to make ahole in the center o the top slabor the lotion pump (fgure 11).Ater the glaze ring, a glue-oncollar and lotion pump collar willcomplete the pot.


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by David Hendley

Rope-top Bucket

Pots with twisted coil rimsand handles have beenmade since ancient times.Lots o beginning pot-

tery students try making pots withtwisted coils, but because o crack-ing during drying and/or ring, theyhave a high ailure rate. Extruding

the coils puts an end to crackingproblems, as well as speeding upthe job considerably.

The main body o this potterybucket is a straightorward throwncylinder; the extruded rim andhandle that give it a unique look.

To make the bucket, use around3 pounds o clay to throw a6-inch diameter cylinder thatsabout 7 inches high. When n-ished, do not cut the pot o o

the bat since youll need to returnit to the wheel later to attach therim. Once the orm has set up toleather-hard, lay a twisted rope-like extrusion on the top edge othe pot (fgure 1), starting withone end and working to the other.Use a cheese cutter or ettlingknie to cut the extrusion to theexact length at an angle along the

Rope-top bucket,8 in. (20 cm) in heightwith ceramic andbrass handle andextruded rim.

twisted lines in the extrusion. Thiswill provide more surace area toachieve a good tight joint.

Attach the rim to the pot, insideand outside by gently pushingclay down and into the bucket

body, then smooth and blend thejoin by slowly rotating the wheeland gently throwing the junc-ture. Pinch and extend the rim atopposite sides o the bucket toorm two lugs or the handle. Adddecorative pellets or coils on eitherside o these lugs, then cut thebucket rom the bat and cover itto allow the moisture level to even


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out. When the rim is leather hard,

punch two holes or the handlebail using a piece o quarter-inchtubing (fgure 2).

Make a clay handle rom ashort piece o the same twistedextrusion by rolling it over ahandle roller (fgure 3). Youcan make a handle roller by glu-ing short pieces o wood trim(quarter round and cove molding)to a board (see inset). Just beorethe handle reaches leather hard,

make a hole with a metal rod

through the length o it.Ater ring, insert a 14-inch longbrass rod and center it. (Brazingrod works well.) Bend the rod 90at each end o the handle with yourhands. Then, at /8 inch rom theend o the rod, use pliers to bend therod outward at a 90 angle. Threadeach end o the rod with a 6-32 met-al cutting die. Threaded brass ballsrom a lamp parts supply companysecure the handle to the bucket.

The same three-lobe die (shown here in

our sizes) is used to make the rim and

the handle. These dies were all made

rom small pieces o Plexiglas that are

inserted in the extruder. Rope dies are

easy to makesimply drill three holes,

then use a jewelers saw to connect the

holes and cut away the center part o

the die. While the extruded coi l does not

look very interesting, once twisted, it has

the appearance o three coils twisted to-

gether. To achieve this look, twist the top

end rst, fip the coil over, twist the other

end, then twist the middle. Youll need a

24-inch extrusion to t a 6-inch pot. Lay

the twisted extrusion in a circle on the

bat around the base o your pot, then

attach it once it has set up a bit.

1 2 3

TIPWhen making the hole

in the handle, push the

rod in about one inch

on one end, then do

the same rom the oth-

er end. Alternate rom

each end until you reach

the middle.


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