Preparing an Object for a Flexible Mold!

There are several ways to approach the making of a flexible mold; variations depend on the type of pattern (object) you are casting and the type of flexible mold making material you choose to use. As you will see, careful and thorough preparation of the pattern is everything!

Let's start with a fairly simple object: A section of flexible wire enforced hose:

I tried to cut the hose even and clip the wire evenly. I then cut a couple of rough circles out of plywood and fitted them to the ends. This makes it easier to make a mold of the hose section. It will register as a solid object, but if I want it to be hollow I can certainly cast it that way later. For now, it is important that the hose be sturdy and that the mold making material not get inside. I braced the object on a scrap piece of board with some clay and filled the joints between the plywood and the hose with sulphur-free oil based clay. The entire object and the wood is sealed with a few coats of thinned shellac. Most flexible compounds require that you seal porous surfaces, including (and especially) wood.

After the object is held steady in place with clay or hot glue and the shellac is dry, I find the center line with a machine square. Where the machine square touches the circular object, I make a mark - this is the center. This is a useful way to find the center of round objects for flexible mold making.

Now I want to make the shim wall for the first half of the flexible mold. I want to use the parting line that I created with the square and I will use a sulphur-free oil based clay the make the shim wall. This is the material specified by the type of rubber I will use for the mold. Most rubber compounds will react badly to water based clay and to any oil-based clay (plastelina) that contains sulphur. Be sure to read all the instructions on the product before beginning so that you have the correct materials to make your mold. Since the object is about 4 -5 inches tall and would take a lot of extra clay to build up a shim wall to the center line, I take a short-cut by cutting out a silhouette in another scrap piece of plywood to fit around the object. I secure it so that it sits just below the center line I made with the square.

I pound out a stick of sulphur-free clay and make a shim wall that sits right at the center line. I carefully work it evenly and smoothly up to the surface of the hose; I don't want any gaps between the object and the clay. Because there is a little bit of a gap between the plywood and the hose, I had to add a little here and there as some of the clay sunk into the gap. I do this all the way around and then trim the clay shim walls to about 3/4" wide.

Presto! The shim wall is complete. If you look closely, I added some keys (thumb-sized depressions in the shim wall that will cast as little bumps in the flexible mold material) and then built a dam to contain the uncured rubber. I am now ready the for next post: Mixing and Applying a Flexible Compound!!

FALL 2011 Syllabus TE 390.1; Casting Techniques

TE 390.1 Casting Techniques; FALL 2011

Location: 430F

Monday 2:00 pm – 6:00 pm

Instructors: Andrew Wilhelm, Betsy Alwin

contacts: sngldbltrpl@hotmail.com / betsyalwin@hotmail.com

Class Overview

The focus of our projects will be the processes and techniques of metal casting. Though we will concentrate primarily on casting bronze, the means by which we realize the finished projects will introduce processes of modeling, mold making and finishing that will carry over into your future studio practice. Our discussion will involve the history of such practices and their place in contemporary art.

The techniques and terminology of casting bronze have not changed much since the alloy was discovered and developed nearly 6000 years ago. The method of “cire perdue” (lost wax) is an ancient method developed in ancient Egypt. Bronze was the chief cast material by which tools and weapons were manufactured and developed during the Bronze Age (3,500 – 1,500 B.C.) Bronze became popular for monuments and statuary, a more versatile and durable alternative to stone carving. As a modern and contemporary art material, bronze has been traditionally used to cast some very untraditional forms and objects.

We will cover several processes of the lost wax technique, concentrating on proper molding techniques, investment, casting and finishing techniques. You will be encouraged to explore new forms and ideas in casting, considering both the possibilities and limits of the material.

Course Objectives:

• Learn and develop mold making techniques
• Practice and understand methods of casting metal: proper use of materials, equipment, and safety.
• Explore and discuss historical and contemporary examples.
• Realize two finished projects in metal.

Required Materials:

Most of the materials you will need for this class will be provided or will be available for purchase from the Sculpture shop.

• All casting wax will be provided as well as venting / gate wax.
• If you require rubber for molds you may purchase rubber by weight from the shop. Be sure to weigh the material used and pay for it immediately.
• You will be charged by the weight of your bronzes and the size of the flask used. Please consider this when planning your projects. If you decide not to keep your bronze you must still pay a fee for the casting materials.

You are required to purchase and keep on hand the following:

• Respirator with filters rated for particulates-(P100).
• Leather boots or shoes for casting.

These two items are for safety. Fully familiarize yourself with the MSDS provided in the shop. The foundry and investment materials contain silica sand. Silica dust irritates the respiratory system and with exposure can cause an illness called silicosis. While working with these materials or in this area you MUST wear your respirator. If you have asthma or other respiratory problems that limit your use of a respirator, please talk with one of the instructors immediately.

Student responsibilities and grading:

Your grade will be assessed in the following manner:

• 30% Class participation (attendance, participation in discussions and team pours)
• 25% First assignment (the amount of time, effort and attention spent / quality of finished project, timely completion)
• 45% Second project (the amount of time, effort and attention spent / use of demonstrated mold-making skills, quality of finished project, timely completion)

We cover a large amount of important information quickly in demonstrations and discussions. You are responsible for any information or demonstrations you miss due to illness or emergency.

Please refer to Cooper Union’s attendance policy. More than two absences will result in one lower letter grade. Three absences may result in mandatory withdrawal of the class. Lateness will not be tolerated. Two late arrivals to class will result in one absence, and will result in one lower letter grade. If you must leave the class early for any reason during the semester, please inform the instructors in advance of the class. Leaving the class early without being excused by the professors in advance will count as an absence.

Because the pours and investments require teamwork, attendance is essential. Casting is a time intensive process. The scheduling of investments and pours require steadfast deadlines for mold making and waxwork. It is common to underestimate the time needed for the process of completing a bronze work. You will make mistakes along the way; this is normal in the learning process. PLAN YOUR TIME WISELY.

Expect to spend at least six hours a week outside of class for your projects.

Late projects policy: All students in the class are expected to participate in critique whether or not they have completed their own assignments on time.

Each day that a project is late the letter grade will be dropped by one third. Students must make an appointment with the instructors to evaluate late projects.

Please speak with the instructors in advance if there are any extenuating circumstances regarding late projects.

GRADING SCALE:

A range: Outstanding performance: commitment to the quality and development of concepts and of work completed, timely completion of all assignments, significant dedication of work outside class time (good balance of time spent proportional to the level of project), highly engaged class participation.

B range: Above average performance: Good quality of work completed, timely completion of assignments, consistent amount of hours outside class time spent to finish project, active class participation.

C range: Average performance: completing all assignments, some hours outside of class time spent on projects, requisite attendance and participation.

D range: Below average performance: completing assignments excessively late and/or minor commitment to the quality of work completed, minor participation and/or excessive lateness, work time spent outside of class not proportional to the scale of project.

F range: Failure: Incomplete projects and/or excessive lateness and/or absences, little commitment to work done outside of class.

Note on finished projects:

Though ambitious projects are welcome, you will not be graded on the scale of your projects per se. You will be graded on your ability to finish what you have begun, management of class time and outside class time, the development of your concepts and ideas through the material, the level and quality of finish you bring to your projects, and the presentation of finished projects in critique.

Course Outline: Subject to change

September 12, week one * there will be a $25 charge for withdrawal after the 18^th.

Introduction.

Slide show.

Foundry orientation.

Demonstration: Wax modeling. Other model materials. Direct sprueing

Investing a centrifuge flask. First assignment: Two Week Project

September 19, Week two

Tour Modern Art Foundry, Queens. MEET AT MAF 9:45 AM

Meet with Andy or Betsy during week for help with projects.

Work on wax pieces, direct sprue systems. Purchase respirators.

September 26, week three

Waxes due. Group investment session. Have respirators for class. Wear work clothes.

Load investments into kiln. Prepare metal for next week. Burn-out over weekend.

October 3, Week four

Pour First project. Devest after pouring. De-gate and recycle cups and sprues. CLEAN UP! Begin working on 2nd project Idea/Drawings

October 10, Week five

QUICK CRITIQUE FIRST ASSIGNMENT

Mold-Making techniques. Casting wax and other materials.

2^nd project ideas.

October 17: Week six

Bronze finishing techniques.

Work on molds for 2^nd project.

October 24, Week seven

Critique 2^nd project. Begin ideas for final project

Sand casting demonstration.

October 31: Week eight

Final project ideas. Indirect sprue systems.

November 7, Week nine

Body casting techniques

Work on final projects

November 14, Week ten

Work on sprue systems

Invest by Thursday night; burn-out over the weekend

November 21st, Week eleven

POUR-Cast final projects. Bring all safety equipment and proper work clothing to class!

Nov. 24th-27th-HAPPY THANKSGIVING! THE SHOP WILL BE CLOSED OVER THE WEEKEND. PLAN ACCORDINGLY

November 28th , Week twelve

Demonstration: Alternatives to toxic methods of casting: FGR and Aquaresin™

Chasing / finishing / welding / technical

December 5th, Week thirteen

Demonstration: Casting techniques in the studio (when you don’t have a foundry)

Work on final project

December 12th, Week fourteen

Individual review of projects / work day

December 19^st: FINAL CRITIQUE. Location TBA.

First Assignment: Texture in Translation

FIRST PROJECT:

Texture in Translation

The goal of this project is to explore the possibilities of bronze surface treatment. As demonstrated in the introductory slide show, bronze has been manipulated in a variety of ways to depict almost any sort of material – from fabric to stone, wood, and water - naming a few. Perhaps more interesting than the direct replication of such materials into bronze are the instances when textures become the carriers of meaning, transforming the object rather than merely restating it.

There are, of course, limitations to how a durable, hard metal surface can suggest certain textures; how might it be possible for it to depict abstract visual cues such as “softness” or “warmth?” The shape and scale of the object you choose to cast are therefore only parts of the conceptual equation. It is imperative to consider stylization, pattern and relief as well as the finishing process and patina.

Your objective is to use texture to transform an object in bronze. This object can be representational, abstract or non-representational. You may use a variety of methods to approach texture: direct translation through casting a texture and applying it to the object, modeling a texture with your hands or using a specific tool to create / modify a surface. In any case, your technique must be developed and applied to your model or to the wax positive.

Sketches due: January 24th

Waxes due: February 7th

Sprue systems and investment due by February 10th

Cast: February 14th

Critique of first assignment: March 7th

Artist examples: Robert Gober, Erika Verzutti, Malia Jensen, Reuben Kadish,

Marc Quinn, Lynda Benglis, August Rodin, Giacometti