Why Use Plasticine Clay?


Plasticine clay lends itself especially well for mold making and casting works and is preferred by professional sculptors as well. And yet, many people confuse plasticine clay with regular modeling clay.
The confusion is actually justified as plasticine feels just like any other putty clay. However, what makes plasticine so popular is that it is an oil based clay that will never ever dry or harden, no matter how long it is left out in the open.
As Plasticine stays flexible, you don’t have to worry about the mold becoming hard or cracking either. And you can simply reuse the same clay after the casting is done. In case needed, the clay can even be warmed to make it soft and usable once again.
Plasticine comes in different degrees of hardness to suit varying applications - sculpting, mask making, mold making, special effects and so on. The soft variety is popularly used in animation and the harder ones are suited for industrial modeling. Automobile designers prefer to design their prototypes using this clay and the same is also used in claymation to design different movable characters.


And EnvironMolds - the popular online store for all kinds of art supplies - stocks various types of clays. EnvironMolds offers regular clay, plastilina clay and even sulfur-free variants that will not inhibit the setting of silicone mold rubbers.

Making Body Molds with Silicone Rubber

Think body molds; think alginates! Indeed, alginate is the material of choice for capturing molds from the live human body as it is completely safe for the skin. This natural organic material sets quickly and the level of detail is also superior.

However, alginate comes with its own set of drawbacks. For instance, alginate can easily tear during demolding. Even if you manage to demold properly, the molds tend to shrink on contact with air as the water evaporates. They will start losing details within a few hours itself and are mostly unusable after 24 hours or so. Therefore, you have to cast them quickly; within an hour or two at best. Again, these are waste molds as you cannot even consider using them for making multiple castings.

Moreover, you cannot cast resins or polyurethanes in alginate molds. They are mostly suitable for plaster casting only.

Another option

Not many people may be aware that silicone rubber can also be used for making body molds! Indeed, skin-safe silicone is available in the market and LifeRite Skin Safe Silicone from the house of EnvironMolds is a good option.

This 2-part RTV silicone rubber is suitable for life casting and can be easily sourced from Artmolds.com. The body molds will turn out tear-resistant and have a long life.

They can be used again and again for making resin, polyurethane or plaster casting, making it possible to replicate multiple copies using the very same mold!

Multi-Purpose Nature of Sodium Silicate

I recently came across water glass – also called liquid glass – on the EnvironMolds website Artmolds.com. I am well aware that sodium carbonate and silicon dioxide react when molten to form sodium silicate and release carbon dioxide. This compound is regularly used in cements, passive fire protection, refractories, textile and lumber processing, and automobiles.



Imagine my surprise when it dawned on me that the same sodium silicate also enjoys patronage in the world of mold making and casting! The potential of sodium silicate in working as an effective deflocculant for clay slips is still understandable.

However, I had no clue that this same compound would help provide an antique finish to ceramics! All you have to do is brush a thrown pot with a solution of sodium silicate. The painted surface is then quickly dried before expanding the pot from inside. What happens is that the thin skin of sodium silicate first hardens when dried with a blow torch or heat gun while the clay still stays soft and malleable. The pressure of expansion from inside cracks the skin to give the pot an instant antique look. The glazed surface looks quite authentic.



EnvironMolds offers Sodium Silicate in aqueous solution that can be used for ceramics, metal mold making, cement and plaster sealing and also as a high temperature adhesive. It is odorless, non-toxic, moisture resistant, non-flammable and comes at a very low cost too.

Alginate Safe for Skin Contact

Alginate is the most commonly used material for making body molds. As it is extracted from seaweed and combined with other harmless substances, alginate can be safely applied on any part of the human body.

In fact, alginate is a natural organic material that is food safe as well. It is used as an ingredient in many food products and is safe to eat. Alginate is also regularly used to capture dental impressions and life casting alginate has evolved from this formula itself. The mold making version is only modified to deliver slower setting times.

All you have to do is mix the alginate powder with water to form a gel like paste. Avoid using hard water for this purpose. The alginate paste can be easily applied on the face, hands, legs, torso or the entire human body too. It will set within a couple of minutes and can be easily demolded by twisting or wriggling the body part.

EnvironMolds provides a range of alginate formulas that capture incredible details and provide an exact reproduction of the body part where it is applied. Apart from the traditional formulas, there is a silica-free version (softer set suitable for babies and small children) and fiber-reinforced version (delayed shrinkage and improved tear strength for larger molds). Check www.artmolds.com/molding-materials/alginate.html for other slower set variations as well.

Of Reusable Mold Making Materials

Regular mold making materials such as clay, alginate, plaster bandages, silicone rubber and polyurethane rubber are good for single use. In other words, you can use them to make a mold once and that is it. While clay, silicone or polyurethane molds can be used multiple times, the material itself cannot be used again to form a new mold.

Perhaps the only reusable mold making material is thermoset mold rubber!

Thermoset mold rubber comes in a box and has to be heated (in a microwave) until it melts completely. Now the molten rubber is directly poured into the mold box to completely cover the model. That’s it, no measuring or mixing is required. It gradually hardens on cooling, and soon a flexible rubber mold is ready for use.

The mold made can be repeatedly used to produce multiple casts without any noticeable degradation whatsoever. And once you are finally done using the thermoset rubber mold, it can easily be melted and reused to make new molds quite effectively. In fact, some thermoset mold rubbers such as Wizbe’s Composi-Mold can be re-melted and reused as many as 35 times!

Three variants of Composi-Mold are available at EnvironMolds website artmolds.com
  • Composi-Mold-LT - a soft flexible rubber which sets similar to a Shore A 10.
  • Composi-Mold-PowerMold - a firmer version for making two part or push molds with Shore A 25 hardness.
  • ComposiMold-FC - a FDA compliant food grade mold rubber.
In sum, thermoset mold rubber is an extremely cost-effective option over the regular polyurethanes for sure!

Don’t let Liquid Latex Ever Freeze!


Liquid latex rubber is lauded as a versatile mold making and casting material. Apart from its widespread usage for making masks, props and other rubber skin products, liquid latex is also the material of choice to duplicate architectural details or to cast plaster, polyester resin and urethane parts. It enjoys great popularity as a special effects makeup product too.

What has won liquid latex scores of patrons is its exceptional strength, tenacity and durability. To add to this, latex also proves to be flexible and is quite inexpensive compared to other materials of the same realm.

However, latex users always need to keep in mind that latex should never be allowed to freeze. In fact, frozen latex is rendered useless and should be discarded. There is no scope of thawing or heating prior to use. So, carefully handle your liquid latex during severe cold spells and store it safely in a sufficiently warm environment (around 72°F / 23°C).

Therefore, when you order your stock of liquid latex rubber during the freezing winter months (whether from EnvironMolds or any other distributor), it has to be shipped to deliver the very next day. This means that you have to select the overnight air shipping option for next day delivery. It will increase the freight cost but guarantees that the liquid latex rubber will reach you in good condition just as you wanted!

Check Out EnvironMolds’ New Life Casting Instruction Manual

For all those artists who have been struggling to make realistic life cast reproductions of the human body, there’s some good news in store. EnvironMolds has just launched a new life casting instruction book on how to create front torso castings from live models.

Penned by Ed McCormick himself, ‘How to Create a Front Torso Casting’ is a 48 page manual with step-by-step instructions on everything from the materials required for making a front torso life cast to the requisite pre-molding and pre-casting preparations. The book will guide you through the minutiae of how to prepare the model and how to apply the mold making material and finish it off with plaster bandages. You will understand the intricacies of demolding the mold from the model’s body and then making the final cast using plaster or silicone rubbers. Once you learn how to finish the casting, a beautifully artistic front torso casting will await your eyes!

Apart from the life casting tutorial, this helpful guide also contains useful information about how to find, hire and work with life casting models. Compensation suggestions and a bonus model release form are also included in the book. You can easily check out the e-book on the ArtMolds blog before purchasing it for $19.95 from Amazon or MagCloud.

The book is especially useful for passionate life casters who find it difficult to attend EnvironMolds’ life casting workshops