Frequently Asked Questions

What kind of molds do you make?

I specialize in plaster molds, especially for slipcast ceramics. These are made of USG #1 Pottery Plaster.

Plaster molds can also be used with other ceramic techniques, and also in some glass making processes, and in other sculptural applications.

I also make silicone rubber molds, used for casting a variety of materials (e.g. plaster, wax, resin).

I do not make RAM dies, although I frequently make models used by factories to make their own dies in-house.

All molds are custom projects. Unlike commercial hobby mold companies, I do not manufacture any stock molds.

What do you need to make a mold?

A plaster mold is cast from a model- either provided by the customer, or made in my studio as a custom modelmaking project. Ideally, the production technique and the mold design should be a major consideration in designing the piece from the start.

If I provide a model, what should it be made of?

If you provide a model it could be made of plaster, fired ceramic, or any rigid, non-porous material- glass, plastic, etc. I can also cast molds from rapid-prototyped or CNC machined models in various materials.

Wooden models can be a problem if the hot moisture of the setting plaster causes the wood swell, so wooden models must be very well sealed.

If you provide a ceramic model, it can be glazed or bisque. If glazed, remember that the mold will reproduce the surface of the glaze, including drips, pin holes, etc. that may not be immediately evident. Relief sculpting or texture that may be visible through the glaze may not have any actual dimension on the glaze surface. A better approach is to use a bisque model and seal it to a shine with a thin cold finish, such as clear acrylic or lacquer spray.

It is very difficult to make a professional-quality multiple-part mold directly from a soft model (plasticine, wet clay). The ideal approach here would be to make a plaster waste mold, then a plaster cast, which would then be cleaned up and used as a model.

I have made molds from many "found objects" but will not make a mold from any manufactured object in which copyrights, patents, or any other design registrations may be in effect.

What will you do to my model?

Depending on the nature of the piece, I may have to fill undercuts with plasticine, to allow the mold section to draw away from the model. This could be anything from minor, almost invisible fills, to significant alteration of the form, which we determine collaboratively.

I will also make and add a part (usually a turned or sculpted plaster shape) to create the pour hole, or "spare". The spare acts as an entry port to fill the mold, a reservoir to feed slip into the cavity as the part is being cast, and as a guide for trimming the opening of the piece.

Despite all precautions, the unexpected can happen and the model could be damaged in the process of making the mold. Please do not ask me to make a plaster mold directly from a model of great monetary or sentimental value.

What if I don’t have a model?

If you wish me to make a model, I will need an appropriate drawing to work from. I will turn, fabricate, or sculpt the model in the most suitable material, usually plaster. Please inquire about design and modelmaking services.

What about shrinkage?

Clay, whether plastic or liquid (slip) shrinks as its water evaporates and the part dries. It then shrinks again when it is fired and gives up its chemically bonded water.  While a low-fired earthenware may shrink less than than 5%, porcelain may shrink up to 15%.

If I make the model, you must provide me with a percentage of shrinkage for your clay body and firing. Dimensions can be re-calculated or a drawing can be mechanically enlarged to compensate.

If you provide the model, you must either make an appropriately oversized model, or accept the shrinkage. If you make a fired ceramic model, please remember to figure on two shrinkages: first, from the firing of the model and then from the firing of the cast part in production.

If you design a ceramic part that fits to a non-ceramic part, try to make the ceramic part first and then fabricate the other part to fit.

Will you make a block-and-case?

In the ceramic industry, where many molds are needed for each product, the mold shop makes a block-and-case. This is a set of master patterns from which many production molds are made- essentially a complete mold for each individual mold section.

I can make a block-and-case but it is rarely necessary for studio production. Often I can make a simple master pattern for each mold section in a way that is simpler than a full block-and-case. These masters are made in gypsum cement or rubber.

To just make one or two molds it isn't worth making any kind of master pattern, you would just work from the original model. To make, say, twenty molds you would want to make some kind of positive master. Somewhere in between is a break-even point, but, again, it depends on the particular project.

Please do not ask me to archive master patterns , cases, models, etc. unless there is an ongoing need for molds, as storage space is at a premium.

Do you do ceramic production?

My specialty is in pre-production development and tooling, While I have facilities for making ceramics, I don't do contract production. I will try to refer you to an appropriate US studio or factory for production.

How many casts can I expect from a mold?

Plaster molds are consumable. This is one reason why a typical commercial pottery will have both a master mold-and-model shop to do original work, and also a production mold shop to continuously produce molds for the production floor.

The usable life of a plaster mold varies with nature of the piece, the slip, and your casting process. Gypsum is slightly soluble in water, so there is a little wear with each casting. In, say, the finest of porcelain figurines, molds are often discarded after 25 casts, due to loss of fine detail. In factories making giftware, sanitary ware or dinnerware, somewhere around 150 casts is typical. On the other hand, I have known studio potters to make many hundreds of casts from molds of simple shapes, where the molds are not pushed too hard (i.e, allowed to dry out)  and the potter is willing to clean up the ware a bit more.

What will a mold cost?

Mold costs vary widely depending on the size and complexity of the piece, the preparation needed, the number of molds needed, etc. I do not fix set prices for molds or models. Prices for custom molds are in no way comparable to prices of stock molds from a hobby mold supplier. Please allow me to quote models and molds on an individual basis. You can send or email drawings or images for quote purposes.

How long will it take to make molds?

I am the only master moldmaker in the studio and every project gets my full attention, so timing varies with the nature of the project and also with the current work load in the studio. To be safe, please allow at least six weeks, although often molds are done faster.

How are the molds shipped?

You can pick up at my Albany, NY studio (which is my preference), or I will ship your mold via UPS or Fedex. Typically, I take the work to my local Mailboxes-type store and pass the packing and shipping costs on to you.

Can I learn moldmaking in your studio?

My studio isn't set up as a teaching facility, and no educational programs are held here. I am available for lectures and workshops and have done many programs at schools, conferences, and craft centers around the country. Please visit the "Workshops" page of this web site.

Can I be certain that I won’t lose control of my design?

It is my practice and my nature to work collaboratively. I do not care to impose my esthetic on your work. I make every effort to get your opinion and approval on esthetic and mechanical decisions so that you will be pleased with the result.

Please rest assured that no molds will be "pirated" from your design and that I will respect your confidentiality as you require. I consider this a non-issue, but the question has been raised in the past.

Recent Shop Talk

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How to design molds for slipcast plates, platters, shallow bowls and similar forms

Solo Show, Bethlehem Public Library, Prints and Drawings, 12/2015

Solo show of Prints, Drawings, and Collages at the Bethlehem (NY) Public Library

Solo Show, Bethlehem Public Library, Collages. 12/2015

A suite of collages with Jokers

Figure Drawings

A few selections of figure drawings from recent years.

“Rookwood for Mottahedeh” shapes

Three shapes for Rookwood/Mottahedeh

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