Sunday, October 31, 2010

Modeling The Head In Clay

I have several head modeling books in my home library. I guess I just enjoy looking at Bruno Luccesi's work.



Modeling The Head In Clay.
Sculpture by Bruno Luccesi. Text and Photographs by Margit Malmstrom.
NY: Watson-Guptill Publications, 1979.
ISBN: 0823030989

I try to do a little work on my doll every day. Today I worked some more on the legs.




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Saturday, October 30, 2010

Modeling The Figure In Clay

Everyday I try to work on my BJD a little bit. When there isn't much to show for my little bit of work, I'm going to share a book that is in my home library. That is more interesting than just saying that I worked some more on the lower leg, right?



Modeling The Figure In Clay: A Sculptor's Guide To Anatomy.
Sculpture by Bruno Luccesi. Text and Photographs by Margit Malmstrom.
NY: Watson-Guptill Publications, 1980.
ISBN: 0823030970

I've had this book for years, and it is still a favorite one to look through, every once in awhile. Building a figure muscle by muscle isn't a good way to model the figure in clay. This is a fun sculpture anatomy book.




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Friday, October 29, 2010

Lower Leg Mold Estimation




This is an example of estimating a plaster mold for the lower leg. The lower leg in the diagram is 7 inches long. The diameter of the knee is 1.5 inches. The diameter of the ankle is 0.875 inches. I can draw the frustum of a cone around the leg that has those dimensions.



In these formulas, the asterisk (*) means multiply.
The forward slash (/) means divide.
The carat (^) means exponent. For example 2^2 means 2*2, or 2 to the power of 2.
Parenthesis (()) are used to group calculations that should be done first, before the others are done.

I can estimate how much volume that leg has using the following formula:

V = ((pi*h)/3)*(R^2 + R*r + r^2)

R = Radius of large end (the radius is one half the diameter, so 1.5 / 2 = .75, or 3/4")
r = radius of small end (.875 / 2 = 0.4375, or 7/16")
h = height of leg = 7"
pi = 3.14

V = ((3.14 * 7) / 3) * ((.75*.75) + (.75*.4375) + (.4375 * .4375))
V = ((21.98) / 3) * ((0.56) + (0.33) + (0.19))
V = ((7.33) * (1.08))
V = 7.9 cubic inches
I can just round the volume off to 8 cubic inches.




The coddles will be a rectangular volume. I want about an inch of plaster all around the leg, and about an inch of plaster over the top of the leg. The leg is embedded about halfway in the clay build-up. So the rectangular volume will be 9.5 inches long, 3.5 inches wide, and 1.75 inches in height.

V = L*W*H

V = 9.5 * 3.5 * 1.75
V = 58.1875 cubic inches
I can round that volume off to 58 cu.in.



Finally, there is the volume of the spare. The spare is where the slip or wax is poured into the mold. I'll use the same formula that I used for the leg, but I'll change the length to 1.5 inches.

V=((3.14 * 1.5) / 3) * ((.75*.75) + (.75*.4375) + (.4375 * .4375))
V = 1.6 cu.in.
I can round that off to 1.5 cu.in.

Now all I have to do is add, subtract, and divide.
I add the volume of the leg and spare together: 8 + 1.5 = 9.5 cu.in
Since the leg is halfway in the clay build-up, I can divide that by 2: 9.5 / 2 = 4.75 cu.in.
The volume of the mold box is 58 cu. in.
58 - 4.75 = 53.25 cu.in.

The volume of a cup of water is 14.6 cu.in.

53.25 / 14.6 = 3.6 cups of water.
I can round that off to 3.5 cups of water.
This is an estimate, after all.

A good consistency for plaster is 67 parts of water to 100 parts of plaster.
That is a ratio of 2:3.
3.5 / 2 = 1.75 (1.75 is one part)
3.5 + 1.75 = 5.25

The ratio of water to plaster will be 3.5 to 5.25.
So first I weigh 3.5 cups of water on the scale.
I take that weight, divide it by 2, and add the result to the weight of the water.
That is the weight of the plaster to add to the water.

I'll have to test this method to make sure I've got it right.




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Thursday, October 28, 2010

Plaster Mold Repair

This is a method for mixing plaster to repair small holes. Add plaster to a small amount of water (2 oz. or less). Sprinkle the plaster until all the water is absorbed. DO NOT mix this plaster. Scoop a little plaster with a small tool (without disturbing the rest of the plaster too much) and quickly apply it to the small repair. This method is good for small holes caused by air bubbles or small chips.




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Wednesday, October 27, 2010

The Figure In Clay




This is a book of inspiration and technique, but mostly inspiration. While it isn't specifically about dolls, per se, there are enough provocative images of clay figure sculpture in this book to fuel the imagination. Some of the best Artist BJDs that I've seen have been more sculptural than doll-like, and they certainly don't fit in the Asian BJD aesthetic, which is just one of many. This book is still available, and you can probably find it in your local library.



The Figure In Clay: Contemporary Sculpting Techniques By Master Artists.
Suzanne J. E. Tourtillott.
NY: Lark Books, 2005.
ISBN: 1579906117




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Tuesday, October 26, 2010

Lower Legs




Today I worked on the lower legs. I'm trying to get them ready for a rough shell mold, and every time I pick them up and look at them, I see places where I can add some wax. Since I've been playing with my carving wax, I feel that it will be better to get a good finish on my wax originals before I cast them in carving wax.




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Monday, October 25, 2010

Creating Lifelike Animals in Polymer Clay




This is another sculpting tutorial for beginners by Katherine Dewey, the same author that wrote Creating Lifelike Figures in Polymer Clay. If you are interested in making an Anthro-BJD, this book might be a useful reference.



Creating Lifelike Figures in Polymer Clay.
Katherine Dewey.
Cincinnati, OH: North Light Books, 2000.
ISBN: 0891349553

Table of Contents

pg 5 Introduction
pg 6 Chapter 1 - A Polymer Clay Primer
pg 9 Chapter 2 - Tools of the Trade
pg 13 Chapter 3 - Mastering the Basics
pg 21 Chapter 4 - Creating Animals Step By Step
pg 22 Project One - The Deer Mouse
pg 32 Project Two - The Young Cottontail
pg 40 Project Three - The Harp Seal
pg 46 Project Four - The Black Bear
pg 56 Project Five - The Basset Hound
pg 66 Project Six - The White-Tailed Fawn
pg 76 Project Seven - The Red Fox
pg 86 Project Eight - The Bull Frog
pg 96 Project Nine - The Fledgling Bluebird
pg 106 Project Ten - The Siamese Kitten
pg 116 Chapter 5 - Changing the Size, Pose, Setting or Finish
pg 127 Resources
pg 128 Index




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Sunday, October 24, 2010

Doll Wig Hair




Halloween is nearing, and the stores are full of Halloween gear. I found these 24 inch long Hair Extensions at the Dollar Tree the other day when I was picking up some Baby Powder Talc for making carving wax. I will use them to make a doll wig.







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Saturday, October 23, 2010

More Carving Wax

Today I added more carving wax to my carving wax stash. I adjusted the candle wax/talc recipe with microcrystalline wax/talc. I now have about 10.5 pounds of carving wax.

While the adjusted carving wax is much better than carving wax/talc recipe, it still isn't as nice as the first carving wax recipe that I made:

14 ounces microcrystalline wax
14 ounces paraffin wax
28 ounces talc (baby powder talc)
2 ounces scented white candle




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Friday, October 22, 2010

Creating Lifelike Figures in Polymer Clay




I recently obtained this book. It looks like an excellent sculpting tutorial for beginners.



Creating Lifelike Figures in Polymer Clay.
Katherine Dewey.
NY: Watson-Guptill Publications, 2000.
ISBN: 0823015033

Table Of Contents
5 Introduction
6 Part 1 - A Medium For Everyone - Polymer Clay Fundamentals
10 Part 2 - Figure Fundamentals - An Overview of Figure Modeling
13 Part 3 - Fundamental Tools - The Essential and Nonessential Tool Kit
20 Part 4 - Face to Face - Modeling the Head and Face
46 Part 5 - The Body in Question - Modeling the Torso
70 Part 6 - A Leg To Stand On - Modeling the Leg & Foot
86 Part 7 - A Show Of Hands - Modeling the Hand & Arm
102 Part 8 - Measure For Measure - Modeling in a Smaller Scale
116 Part 9 - Costumes of Clay - Dressing the Sculpture in Polymer Clay
130 Part 10 - Finishing Touches - Adding Details with paint and Fiber
143 Resources
144 Index

The author's website:
http://www.elvenwork.com/tips.html




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Thursday, October 21, 2010

Plaster Mold Making Tool - The Work Surface




Traditionally, the best working surface is marble; also very good is plastic laminate sheet, such as Formica, which can be mounted to the tabletop. Either material will provide a fine, smooth surface on which to cast, and will take pencil marking well, which is necessary in laying out guide lines. Some craftsmen use a sheet of heavy plate glass as a work surface. Plaster Mold and Model Making. Chaney & Skee. p.14.

I have a piece of heavy plate glass, 22"x22"x0.5", mounted on a plywood modeling board.





Here it is leaning against the easel.





This is the back of the plywood, showing the strips of wood that make it easy to get my fingers under the board, for moving it.





This is the plate glass on a modeling stand, made from an old floor stand for a fan. That cast iron base is good and heavy. It can be raised and lowered.






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Wednesday, October 20, 2010

Plaster Mold Making Tool - Vibrator




The Plaster Mold Making Vibrator is bolted to the side of my plaster molding table with the Formica table top. It is a small used motor that I purchased at a yard sale, many years ago for about $5. Any 1/4 or 1/3 horsepower electric motor will work.






The part that makes the electric motor vibrate the table is the eccentric steel disk that is fastened to the shaft of the motor. How it works is, my mold is ready to pour, the plaster is mixed and ready to pour, I plug in the motor and it vibrates the table while I pour the plaster. The vibration helps the plaster flow over every part in the mold box, and it also minimizes bubbles.






This is a diagram of the steel disk with the off-center (eccentric) hole for the shaft of the motor. It is this eccentric disk that makes the vibration. Since the motor is firmly bolted to the molding table, the table and everything on it also vibrates.


For more vibration, offset the hole for the shaft more. This tool is also useful for pouring any liquid into a mold that would benefit from being vibrated while poured.




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Tuesday, October 19, 2010

Estimating Plaster For Slip Casting Molds




I'm working on the Plaster Molds For Slip Casting post in the Martha's Method thread at Woodland Earth Studio, and as I go through the process in my head, I make diagrams to illustrate the process. The diagram is Not To Scale.



Being a rather frugal molder, I like to estimate the volume of plaster that I'm going to pour. There are several things to take into consideration when making an estimate. The first thing to consider is the size of the pattern to be molded. In the above illustration, I'm making a mold of a sphere to be used as a hip joint. In this case, the sphere is 2 inches in diameter. There will also be a spare, used to pour carving wax, or slip into the mold. The spare has a cup shape, with the small end of the cup attached to the sphere, and the large end of the cup attached to the wall of the mold box, or coddle. So the first thing I need to do is some arithmetic to figure out how big these two items are. Fortunately, there are some formulas that can be used to do this that are brilliant.

In these formulas, the asterisk (*) means multiply.
The forward slash (/) means divide.
The carat (^#) means exponent. For example 2^2 means 2*2, or 2 to the power of 2.
Parenthesis (()) are used to group calculations that should be done first, before the others are done.

Formula to figure the volume of a sphere:
(4 / 3) * pi * r^3
The diameter of the sphere is 2 inches, so the radius is 1.
pi is 3.14.
The volume of the sphere is 1.33 * 3.14 * (1*1*1), which equals 4.1762 cu. in.
Jot that number down.

The spare must be large enough to pour carving wax or slip into, and after the walls of the casting are thick enough, large enough to pour the excess casting liquid out of the mold without leaving too large of a hole in the casting. For a small casting like this sphere, I think a 1/4 inch hole (.25") should be enough. I want the walls of the casting to be at least 1/8th inch thick, so, adding all that up comes to 1/2 inch. At the top, a 1 inch diameter should be large enough to pour into, and a 1 inch length should be sufficient to feed a casting that will have 1/8th inch thick walls. So the spare is a cup shape that is 1 inch in height, 1 inch diameter at the large end (.5 inch radius), and 1/2 inch diameter at the small end (.25 inch radius).

Formula to figure the volume of the spare:
((pi*h)/3)*(R^2 + R*r + r^2)
where R = radius of base circle;
r = radius of top circle;
and h = distance from base to top.
3.14 * 1 = 3.14
3.14 / 3 = 1.04666
.5 * .5 = .25
.50 * .25 = .125
.25 * .25 = .0625
.25 + .125 + .0625 = .4375
1.04666 * .4375 = .45791 cubic inch.

Since the sphere and the spare will be embedded halfway in a clay build up, to make a 2-piece plaster mold, I need to add the volumes together and divide the answer by two.

4.1762 cu.in. + .4375 cu.in. = 4.6137

4.6137 / 2 = 2.30685 cu.in.
Jot that number down.

Next, I need to figure out the volume of the first half of the plaster mold. I'll make the mold with 1 inch of space all around the sphere. The sphere is 2 inches in diameter, so 2+1+1=4. My mold box will have an area of 4 by 4 inches. Half of the sphere will be embedded in a clay build-up, so 1 inch will be sticking up. An inch thickness above the top of the sphere will be 2 inches deep. So the mold box will hold 4*4*2 cubic inches of plaster, or 32 cubic inches. Next, I'll subtract the volume of the spare and the sphere.

32 - 2.30685 = 29.69315 cubic inches of plaster is needed for each side of the mold.

How many cubic inches are in a cup?
One U.S. legal cup (240ml) is equal to 14.6456 cubic inches.
For reference:
1 milliliter (ml) = 1 cubic centimeter (cm^3)
1in = 2.54cm, so 1/2.54 gives us
1cm = 0.3937in
One 240ml cup occupies any theoretical space measuring 240cm^3.

29.69315/14.6456
2.02744

I can estimate that I'll need two cups of water to fill the volume of each mold half.
A good consistency for slip casting molds is 67 parts water to 100 parts plaster by weight.
This is a ratio of 2:3 by weight.

16 ounces of clean tap water weighs about 1 pound.
1 pound divided by two is 1/2 pound.
1/2 pound times 3 is 1-1/2 pounds.

1 pound of water to 1-1/2 pounds of plaster is a 2:3 ratio by weight.

The following diagrams show the formulas that I used in this estimate.



















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Monday, October 18, 2010

New Lower Torso




I try to do a little bit of work on my BJD every day. Today I worked a little bit on the new lower torso. As you can see from the photo, the new lower torso is a wee bit longer than the old one. The comparison is between the carving wax torso, cast in the plaster rough shell mold of the old lower torso, and the old wax torso, heavily modified. Not only did I cut the old solid wax lower torso, but I also hollowed it out before I made the mods. I should be able to drill holes in this torso and lightly string it to the upper legs and upper torso, if I want to, before molding it to cast the carving wax lower torso. It does not look hollow, but it is.






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Sunday, October 17, 2010

Plaster Mold Making




In order to make a porcelain BJD, it is necessary to make plaster molds to pour porcelain slip into. More care is taken to make these molds than was taken to make the rough shell molds. These are the molds that the final ball-jointed doll will be cast into. At this point in the process, finished carving wax doll parts have been made, ball-joints added; they've been test strung and sanded smooth.

All of these parts will be put in a clay build-up which divides the parts along the parting line. Coddles will be placed around the clay build-up and sealed with clay. A clay spare may be added. The model will be brushed with a parting agent. The volume of plaster needed will be calculated. Water is put in a mixing bowl. Plaster is sifted into the water. The plaster is allowed to slack for one to three minutes. Mixing is then done by hand, or with tools. The mix is poured. Excess plaster is discarded into the trash bin. The mixing bowl is rinsed in a bucket of water (Never put plaster, dry, wet, or set into the drain!). The mix sets up into a hard solid. That makes the first piece of a multiple-part mold.

The coddles are removed and the mold is turned over. The clay build-up is carefully removed, without disturbing the doll part. Registration keys are carved in at least three places. Coddles will be placed around the plaster mold and sealed with clay. The other half of the clay spare may be added. The model will be brushed with a parting agent. The volume of plaster needed will be calculated. Water is put in a mixing bowl. Plaster is sifted into the water. The plaster is allowed to slack for one to three minutes. Mixing is then done by hand, or with tools. The mix is poured. Excess plaster is discarded into the trash bin. The mixing bowl is rinsed in a bucket of water (Never put plaster, dry, wet, or set into the drain!). The mix sets up into a hard solid. That makes the second piece of a multiple-part mold.

If a third mold piece is necessary, the same procedure that was used to make the second piece of the mold is followed. The clay build-up for the third piece of the mold is carefully removed, without disturbing the doll part. Registration keys are carved. A parting agent is applied. The volume of plaster needed is calculated. The plaster is mixed, poured, and allowed to set up.

Once all the pieces of the mold have been made, the mold is taken apart and the edges are beveled. The mold is cleaned, then put back together and held with thick rubber bands, so the mold will not warp. The mold must be put in a dry ventilated place so it can dry. A dry plaster mold will absorb water, and this is the property of plaster that makes it so useful for slip casting porcelain.



In the above diagram, the mold making process is shown.

1. The torso is being molded. Here the torso is shown in a clay build-up. The clay is green. It is important to build the clay up to the parting line of the torso. There must be no undercuts.
2. The torso is shown with a clay spare added, as well as clay build-ups for the hip sockets. The coddles have been put in place and clamped securely. The edges have been sealed with clay. Parting agent has been brushed on the torso. The first half of the mold is ready to be poured.
3. After pouring plaster into the first half of the mold, the mold is turned over, and the clay build-up is carefully removed. The other half of the clay build-up for the spare, and the other halves of the clay build-up for the hip sockets are made. Registration keys are carved into the first half of the plaster mold. Parting agent is applied to the torso and to all the plaster area that is showing from the first half of the mold. The second half of the mold is ready to be poured. The coddles should be clamped and all the edges sealed with clay.
4. In (4a) we see that both halves of the plaster mold have been poured, leaving the clay build-ups for the hip sockets. These clay build-ups are removed, cleaned, registration keys carved, and parting agent applied. In (4b) plaster is mixed and poured into the hip socket areas. In (4c) we can see that the mold has been separated, showing the clay build-up for the spare, the torso embedded in one half of the plaster, and the two plaster pieces for the hip sockets in place. The torso is removed, the clay build-up for the spare is removed, the mold edges are beveled with a knife, the mold is cleaned up, banded together, and put aside to dry.






My coddles are made from dimensioned lumber from the hardware store. 1x4 lumber is actually 3/4ths X 3-1/2 inches X length. 2x2 lumber is actually 1-1/2 X 1-1/2 inches X length. I cut all the pieces, then glue and screw the 2x2 to the 1x4. After the glue is dry, I coat all the surfaces of the coddles with several coats of shellac, letting each coat dry inbetween coats. My coddles have been in mold making service for many years now.

How long should you make your coddles? What are you going to be molding? For dolls, a torso is about the largest part that needs to be molded. The length of the torso, plus a spare, plus hip socket parts, plus a few inches extra length should be sufficient. For example, a torso that is 6 inches long, with a 2 inch spare, and 3 inch hip socket pieces, plus 2 or 3 inches extra, adds up to about 14 inches long. Of course, the doll I am making is a 60cm doll.




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Saturday, October 16, 2010

Volume Formulas 01




I'm starting to work on some mold making arithmetic. What I'm trying to figure out is how many cubic inches are in my mold box, and how many cubic inches my doll part is. I will subtract the cubic inches of my doll part from the cubic inches in my mold box to come up with an estimate of the volume of plaster I will need to mix. I use an arbitrary precision calculator called bc that allows me to assign values to variables.

l=4
w=3
h=2

v=l*w*h
v
24



A mold box that has the inside dimensions of 4 inches long, 3 inches wide, and 2 inches deep, is 24 cubic inches in volume. That can also be written as 24in^3, or 24cu.in..

For plaster molds that use coddles, the rectangular prism will be the volume used the most for the mold form. It is also a handy volume to figure out more complex forms that are being molded, since the more complex forms can usually be surround by a rectangle of some sort, and a height can be assigned to each rectangle.



pi=3.14
r=1.5

v=(4/3)*pi*r^3
v
14.12994



In the above formula, r is the radius of the sphere. If the sphere has a diameter of 3 inches, then the radius is one half the diameter, or 1.5 inches. pi is an infinite number that I have rounded off to 3.14. Pi actually looks more like 3.1415926.... The balls in ball-joints are usually spheres.



pi=3.14
r=0.75
h=4.5
v=pi*r^2*h
v
7.94812



Use the volume of a cylinder to estimate limbs, like arms and legs.




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Friday, October 15, 2010

Stringing Joints With Springs




Today I posted another installment to Martha's Method over at the Woodland Earth Studio forum. This post is about stringing a BJD using the spring-tensioning stringing method. I've been thinking about it for quite some time now. When I do think about it, I usually end up making some quick sketches in a simple paint program called Kolourpaint. I like it because I don't really have to think about how to do anything, I can just sketch quickly with my mouse, using basic shapes. These are some of my quick sketches about spring-tensioned stringing of a BJD.





















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Thursday, October 14, 2010

Carving Wax Casts

Today I tinkered around with my carving wax casts. I made two casts yesterday. The first one was left in the mold about a minute or so before I emptied the excess wax out. The thickness of the wall in the spare looked like it was about 1/8th inch thick. That casting turned out to be about 1/16th inch thick! Wow! That means the spare is giving me inaccurate information! Maybe it has something to do with the temperature of the wax I am pouring? I poured the first mold at about 160 degrees Fahrenheit.

The second casting was left in the mold about two minutes. Also, I poured it at a lower temperature of about 150 degrees Fahrenheit. It came out about 1/8th inch thick. The thickness of the wax in the spare looked to be more than 1/4 inch thick!

From this small sampling, I think that both the temperature that the wax is poured, and the time that it is left in the mold, are more important indicators of wall thickness than how thick the wax wall looks in the spare! I'll need to keep track of this information.

What I really like about both of these castings is that when I thump them with my finger, they sound like plastic. They are hard. They can be carved with my paring knife. They can be drilled with a drill bit. They can be sanded smooth. This is why Martha Armstrong-Hand worked with carving wax!

The carving wax pattern can be used to make silicon rubber molds for resin casting, or plaster slip casting molds for porcelain. I am just now beginning to understand why professional designers use Industrial Design Carving Wax! This material is incredible.

It doesn't matter what you make the original sculpt from. If you can make a rough shell mold of plaster from that sculpt, then you can cast carving wax into that mold. Once you have the carving wax pattern, you can add/subtract to/from that pattern, and finish it as smooth as you want to finish it. Then you can make your final casting mold from that pattern. This is the secret of Martha's Method. I haven't seen it anywhere else.




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Wednesday, October 13, 2010

Lower Torso Casting in Carving Wax




Today I cast a couple of lower torsos in carving wax from the mold I made yesterday. First of all I started melting the new batch of carving wax. I wanted to see if a small addition of microcrystalline wax would be enough to make it useful. I added 3oz of brown microcrystalline wax to the melt. Martha Armstrong-Hand's carving wax recipe is 9:9:1:1 of paraffin, industrial talc, beeswax, and carnauba wax. That is 20 parts total. 1/20th of 56oz is about 3oz. I used microcrystalline wax because that is what I have on hand in my studio.

The plaster mold needed to be soaked until completely saturated with water. Water and wax don't mix, so wax will not stick to a water-saturated plaster mold. I also soaked my plaster mold that I use to pour excess wax into when I'm finished. Finally, after the wax has melted, and the molds have had the excess water dabbed out of them with a soft cloth, I use some heavy rubber bands to secure the mold halves together, so the hydrostatic pressure of molten wax won't force the halves apart, spilling the wax from the mold onto the floor.

I set the mold with the pouring sprue upright, and holding the wax pot with leather gloves, I carefully pour the mold full of wax in one continuous stream of wax, so as to avoid any stop-and-go lines on the casting. Here are some photos of today's castings.





















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