Slip

^7- 10 Reeves Kona f4 34% Grolleg 40% Flint 26% Also about 35% darvan 7 .35% Spelth 8-10 Custer Feld 18% Tile 6 12% Ball Clay 8% Flint 20% Pyrotrol (pyrax) 12% Also about 40% water Davan 7 .35% Always add the darvan to warm water. then add ingredients mixing as you go. add lightest first - if in doubt pick some up and see how fluffy or dense it is. ex: Kaolins first grolleg Tile 6 EPK Other clays Ball clay OM4 Ten Ten etc Med Density Silica Pyrax Last Nephy Sy feldspars

Things that are good to have:

There is a lot of stuff on this list.  You definitely need some of your own tools. You probably want the sand paper.  You need a respirator. And you need plaster to make molds.  The rest of the stuff depends on how much you like to work on your own, how much you will be doing in the future, etc... 


The Clay Shop

Mud Tools!   I like a couple of yellow and green with a variety of corner shapes. http://www.theceramicshop.com/store/category/11/203/Ribs/Rubber/

Brushes-these are nice to have, any selection will do
http://www.theceramicshop.com/store/product/5076/Brush-Set-Talkon/

A rubber finger tool! I can't make a mold or build anything without it.
http://www.theceramicshop.com/store/product/1512/Wipe-Out-Tool%2C-Rubber-Shaper/

If you still need the basics- this is great:
http://www.theceramicshop.com/store/product/1690/Ceramic-Student-Tool-Kit/

Plaster
http://www.theceramicshop.com/store/product/395/Pottery-Plaster-%231/

At any store or from your home

Murphy's Oil Soap

A collection of small containers - Chinese Soup type

A towl

An Apron

A large sponge for clean up (its always good to have your own.


This stuff is at Home Depot or Lowes in the painting department-

A couple of buckets for mixing and to keep slip in
http://www.homedepot.com/h_d1/N-5yc1v/R-202264039/h_d2/ProductDisplay?langId=-1&storeId=10051&catalogId=10053

You also might want a variety of wet/dry sand paper:

Silicon Carbide Drywall Sanding Sheets

400-600 grit 

http://www.homedepot.com/h_d1/N-5yc1v/R-100130840/h_d2/ProductDisplay?langId=-1&storeId=10051&catalogId=10053

and drywall screens - I like about 200 grit

 http://www.homedepot.com/h_d1/N-5yc1v/R-100321140/h_d2/ProductDisplay?langId=-1&storeId=10051&catalogId=10053

Resperator

http://www.homedepot.com/h_d1/N-5yc1v/R-202080143/h_d2/ProductDisplay?langId=-1&storeId=10051&catalogId=10053

or http://www.homedepot.com/h_d1/N-5yc1v/R-100072189/h_d2/ProductDisplay?langId=-1&storeId=10051&catalogId=10053

Blue Painting tape

Also in the Home Depot roofing department

You may want to have your own flashing... or you can share.

http://www.homedepot.com/h_d1/N-5yc1v/R-100071450/h_d2/ProductDisplay?langId=-1&storeId=10051&catalogId=10053

Sprayer Use

To use the sprayer, put on respirator and consider using ear plugs.  

1. Turn on fan on booth.
2. Put well mixed glaze into sprayer.
3. Attach sprayer to hose- making sure that the gasket is locked onto the sprayer.  (do not put on at an angle- do not force).
4. Set pressure on compressor to between 50-75.  Turn up or down as needed to get it to where it feels right. Remember to not let the left gage go over 70.  Use the safety ring to release this pressure.  It will be loud.
5. It is a good idea to lay down plastic to make clean up easy and to be able to recycle extra glaze.
6. Do a test spray on the wall of the sprayer before spraying the actual piece.  A lazy Susan is a good idea to keep the piece rotating.  Change the angle of the sprayer to reach top and bottom. Let each layer dry before applying the next to avoid bubbles and drips.
7. Turn off compressor when taking a break and bleep pressure with ring.
8. I recommend being at almost eye level with the piece when doing the sides.
9. Layer colors as needed.
   
   When finished:
10. Turn off compressor. 
11. Turn off fan.  
12. Bleed compressor.  
13. Remove Sprayer.  
14. Empty glaze.  
15. Recycle and glaze on plastic. 
16. Run warm water into sprayer.  
17. Reattach sprayer. 
18. Turn on compressor.  
19. With a clean sponge spray booth in sections and wipe off.  
20. Repeat until clean. 
21. Turn off compressor 
22. Bleed lines completely
23. Wash off Sprayer and put away.

Don't forget to resister for the next section! Starting November 16th!

Intermediate/Advanced Handbuilding Techniques - Secrets Revealed Wednesdays, 1 - 4 pm, Class #D15 Patti Nelson

From the beginner to the experienced- Find out how to make your ideas into reality!

This class will reveal secrets of top ceramic artists for more successful hand building. From building large, to building thin and strong, patch and repair, avoiding cracks, plus paper clay, staining, marbling clay and much more. This demonstration/tutorial class is sure to inspire and stretch imagination and skills for functional and sculptural artists at all levels.

 Special Projects in Slip and Plaster Wednesdays, 7 - 10 pm, Class #E16 Patti Nelson

Every had an idea and had no idea how to do it, been told it couldn''t be done? Or couldn't be done in the class that you were in?

Join us in this class with no boundaries! Learn to ask not if but how!

Designed to introduce functional and sculptural artists to the range of possibilities in working with slip and plaster. Students will learn to utilize plaster as a tool in simple and complex mold making, (slip and press molds), and as a tool for pushing the range of using clay and casting slip functionally and sculpturally. Additionally, slip will be introduced as a material to be combined with organic materials (from flowers to fabric) to create forms without limitations. Potters and hand-builders alike will find tools to expand their current work with embellishment and production methods, as well as having new ways of working presented. Whether you have ever made a mold or not, you are sure to find exciting new possibilities in this class. Pair new skills with wheel, hand-building or other methods you have loved in the past to expand your universe!

Figurative artists to look at...

http://www.arniezimmerman.com/

http://www.nolenstudios.com/

http://sergeiisupov.com/

Where to buy stuff...

http://www.theceramicshop.com/store/




View Larger Map

The other place to buy stuff if you want more options is Ceramic Supply of Ny & Nj, Lodi, NJ.  You will most likely have it delivered if you buy it from here...

http://ceramicsupplyinc.com/

Great Artists to look at!

http://www.anellegandelman.com/anat.html

http://www.claretwomey.com/

Judy Moonelis

http://www.nualaodonovan.com/

http://www.juliakunin.com/

http://www.gallery4allarts.com/andrea%20szocs.htm

Plaster 101

What is plaster:

Plaster comes from a naturally occurring mineral state. Pottery Plaster #1 is a Gypsum based plaster.

When it is heated to about 300 degrees f it becomes a powder.  The water of crystallization has been removed.

When you re-hydrate the material, the molecules are able to take up this water, and form new inter-locking crystals. This we recognize as set plaster.  These interlocking crystals are a chemical reaction and create a sponge like quality that work to absorb the moister from clay.

Heat and cold will break down this structure.

In order for plaster to have the relationship with clay that we want, it is important that it is mixed in a way that the correct crystalline structure is developed.

To Mix:

Make sure the plaster feels soft and powdery (if there are hard lumps it may have been exposed to moisture)

Measure a little less water then you think will fill up the area you want to cover

Slake the plaster into the water, not too slow, not too fast-breaking up any lumps as you go

watch for the chemical reaction to occur where the plaster starts to sit on the surface of the water (not just a lump in the middle of the plaster)

Let plaster sit in water 2-3 minutes

Agitate until you can see a finger trail in the slip that disappears quickly

Mist with rubbing Alcohol to pop bubbles

Pour steadily into your mold, trying not to create air bubbles

Agitate the mold

Mist with rubbing Alcohol to pop bubbles

You can release carefully when warm or after warmth has cooled (anywhere from 20 min- 1hour)

Wet sand to clean up and compress plaster.

Mold Making

3 things to consider:

What is the material the positive is made from? Is it porous, non- porous, and will the heating of the plaster possibly cause and expansion?

What does the object look like- does it have undercuts or details that are important to maintain?

What is your plan with the final objects?  Do you need the objects to be soft for further modification?  If so, you may need additional parts of the mold for easy release.

1.     Decide if you want to use a clay bed to lay your object on or if you want to lay it directly on the surface (the clay bed is easier to seal. 

2.     Soap your object if porous. Polish it to a silky finish.

3.     Determine where your walls need to be for each section before you start.  This will ensure that you are working smart not hard.  Use a clay maquette or a sketch to help you.  If you don’t care about the object you can also use a sharpie directly on the object.

4.     Using slabs, create walls for each section.  Be careful to seal each section (rubber finger tools work great for this.) Mix and pour plaster one section at a time. Let each section set up.  Make keys, then pour the next section.

5.     Use the amount of clay it takes to properly caulk any cracks.  Wipe away any extra clay.  A small amount of clay can seal without creating a large seem.

6.     After the mold has been poured and has set, gently vibrate the mold apart.  Remove the positive.  Put the mold back together for cleaning so that  you don’t inadvertently clean the fettle lines (the place where the mold pieces meet up on the interior of the mold. )

Sanding the mold compresses the mold, gets rid of plaster that might chip off, and helps it to last in the future. 

Slip:

Even store bought slip should be sieved before use.  This eliminates lumps that will have to be sanded out later and allows even water distribution. 

Deflocculate: To literally break up the “flock” of clay particles by creating a negative charge and causing particles to repel each other.  This allows us to add less water with more fluidity and allows particles to bond with better compression and with out air bubbles.  We add this deflocculant to slip (Darvan or Sodium Silicate)

Coddle: The objects which contain our plaster while it sets around the object we are casting.  Sometimes Aluminum Flashing, or boards we clamp together.

Fettle: The seam of the mold. 

Fettle Line: The line of an object where the undercut occurs (often still visible on plastic cast objects, such as pens)

Undercut: The point where if an immoveable object (such as set plaster) is wrapped around it will become locked and cannot be removed.

Key: the small indentation that keeps a mold from sliding apart.  Two primary types: Standard Keys and Slide Keys.

Mixing Slip

When mixing slip there are a few considerations to take into effect:

Start with about 5 % warm water.

Add your deflocculant to the warm water. Because the defocculant is likely to be less then 1% of the recipe, it is important to measure it carefully either by weight or by volume.

Beginning with the lightest ingredient mix ingredients one at a time to avoid pancaking later.

Every clay/slip will have a clay, a flux (melting agent), a glass maker, and most likely has a filler.  Sometimes ingredients will do double duties.

Kaolins (porcelains) will be lightest, ball clays next, other clays next, then things like talc, silica, and feldspars are likely to be the heaviest.  You can do a simple touch test to determine density.

Sieve and add water to get to desired consistency based on your needs.  I recommend double sieving at about a 40/60  and 80/100.

When recycling slip, its best to dry it out completely then add warm water and double sieve.  If you have used a Darvan as your deflocculant, you will not need to add more.  If you have used sodium silicate, recycle your slip as above, then test the webbing properties.  If it is not webbing properly, add sodium silicate a tiny drop at a time. Go slow with this and be careful not to add too much water until the deflocculation is complete.  To avoid this, use a Darvan.

Tips:
Over deflocculation and under deflocculation look almost the same.  Vinegar will cut deflocculation, go slow and if in doubt, revisit it the next day.

I have found that slip is best after sitting for a day.

Paper Slip

Paper slip is a good solution for surface tension cracks.  If you are experiencing cracking in your process, a small amount of paper can help your situation.

It is important to note a couple of things:
Adding paper to clay may strengthen it while wet, bone dry and during firing, but may weaken it in the final fired state.
If the paper is not disintegrated well it can add texture, you may or may not want this.
Paper will rot, and smell.
Paper added into slip can make it very difficult to re-sieve.

For the above reasons, I recommend using the minimum amount necessary, and to mix paper slips in small amounts at a time to negate the need to re-sieve that batch of slip.

Use cheep toilette paper.  It has less glue and breaks up easily.  Tear it up very small, a food processor can work great on dry paper.

For a gallon of slip, 15-20 squares can be plenty.

Add it to warm water with a tea spoon of vinegar.  I like to let it sit over night. Blend it with a hand blender until paper is completely dispersed in the water.  Then just add to well sieved slip, blend well, and use as normal.

"THE" book to own

The most important thing to remember!

Intro to our blog

Hi Everyone, This is the blog that will carry technical information, images and notes from Wednesday classes at Cheltenham Center for the Arts. Please feel free to create posts, make comments, and upload images. This should be an interactive online extension of class. Both Handbuilding and Special Projects will share this blog, because much of our information can be useful to both groups. I will tag all posts for the class they are relevant to, but feel free to read all!