Tuesday, March 11, 2014
09 Plaster Production Molds Nº 1
Wow !!! I cannot believe that I am actually doing this. What happened to my resolve to do this process in order? If the truth be told, I am fairly certain that I finally admitted to myself that I am stuck.
By my very nature I was determined to finish refining all the carving wax parts before starting on the plaster production molds. I must admit that I was dreading the refining part of the process. I detest sanding anything. The more difficult it is to sand, the more I detest it.
Google Search: define:detest
1. dislike intensely.
"of all birds the carrion crow is the most detested by gamekeepers"
synonyms: abhor, hate, loathe, despise, shrink from, be unable to bear, find intolerable, dislike, disdain, have an aversion to;
"the only vegetable I truly detest is turnip"
(that's really funny because I have a taste aversion to turnips !)
Maybe that is one reason I have not tried the LaDoll modeling material? Besides the fact that it is extremely expensive and not reusable, it seems to me, from everything I have read about it, that it is a material that is mainly shaped by sanding ? Yeah, right. Like I am going to be attracted to a material that requires a lot of sanding ?
Thank Goddess for carving wax !!!. Not only can I get really close to the final form with cast carving wax parts made from modeled oil-clay, but the sanding of carving wax is probably the least obnoxious of any material that I have ever worked with. Yay !!!.
With this post, I am starting to make plaster production molds. I am starting with the feet. According to Way of the Doll the feet are first because they represent being grounded. I can relate to that because I am a Virgo, and Virgo is an Earth sign. Feet support the whole weight of the doll. They will be cast solid. This is an important point. Some parts are cast hollow, and others are cast solid. The feet and the hands are cast solid. The main difference is in the design of the spare. The spare is the pouring cup of the mold.
If a part is to be cast hollow, then the spare should allow for the excess slip to be poured back into the slip jar after the casting has become the desired thickness. If the part is to be cast solid, then the spare does not have to be designed with that in mind. Keep this in mind.
Besides the design of the spare, there are many other things that I need to remind myself of when making plaster molds. Plaster molds are rigid, and unforgiving. Planning is needed. Planning is best done when the whole process is understood. Most of the anxiety of making a plaster mold can be avoided by simply being prepared.
Being prepared means knowing which tools and materials are needed to make plaster production molds, and getting everything together ahead of time.
In the following posts I will be going over everything that will be needed to make plaster production molds and I will document all the molds that I make.
I must admit that I have many tools and materials that a beginner may not have. I have been making sculpture for awhile now, so I have accumulated many materials and tools. I will try to mention alternate methods and tools where needed.
The thing is, I was once a beginner myself, without all these tools and materials. I did not always have such a nice studio. So please ask questions if you have them. I do not expect many questions. It seems that I always go SO slow that all the questions are answered before they can be asked.
The plaster I use for making the production molds is called White Moulding Plaster, also known as No.1 Industrial Moulding Plaster. I purchase this plaster from a local Building Materials Store in a 100 pound sack. When I first started making rigid plaster slip casting molds, that sack cost about $11.00 USD. The last 100 pound sack I purchased cost $44.00 USD.
My plaster mold making bible is Plaster Mold and Model Making by Chaney & Skee.
Plaster Mold and Model Making.
Charles Chaney, Stanley Skee.
NY: Prentice Hall Press, 1986.
(Originally published by:
NY: Van Nostrand Reinhold Company, Inc., 1973. ISBN: 0442215118)
As of the time of this post, this book is out-of-print, but still available from used-book search engines such as AddAll. I highly recommend obtaining a copy of this book if you can. I found my first copy of Chaney&Skee through the Inter-Library Loan service at my local Public Library. You can find libraries that have a book in their collection by searching WorldCat.
It is only fair to note that the above book does not address making doll molds specifically. Rather, it is a book that covers the principles of making plaster molds. Therefore, once the principles are understood, plaster molds may be designed and made for just about any model or pattern that a plaster mold can be made from.
Here is a list of plaster mold making books that I have in my studio.
There is also some very good information about making plaster molds for ball-jointed dolls in the Making a Porcelain Ball Jointed Doll Tutorial and the Martha's Method topic at Woodland Earth Studio.
This post about making a plaster mold from a hard-boiled egg provides a good overview of making a two-piece plaster mold. The same process can be used for making a mold of any round object, such as a ping-pong ball, or a wooden ball if it is sealed first. The idea is that these objects are small, so a lot of plaster is not needed. Also the egg or ping-pong ball is a demanding pattern. If you do not get the parting line just right, it will be locked in one half of the mold. If a mistake is made while learning, losing a hard-boiled egg or a ping-pong ball is not as traumatic as losing a doll part that has many hours of work invested in it.
The important thing, whether you have a book, or are using an online tutorial as a reference, is to understand the process first, then get all the tools and materials that are needed, then practice making some small ball molds before trying to mold any doll parts.
Links To BJD Tutorials
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