Casting and Creating Modeling Work With EnvironMolds, LLC

Enlarging a mold or cast is an easy and enjoyable process. Specially formulated polyurethanes and other compounds are available that allow for scaled expansion of a model.

However, shrinking a cast is a different ballgame altogether. You may consider using materials like alginate, wax or latex rubber that shrink during curing. However, the shrinkage is not proportionate and you will only end up with a deformed version of the original.

What you desire is uniform and balanced reduction with the details staying proportionate to the reduced size!

This is still possible by using special solvents. For this purpose, the original mold should be resistant to solvents or coated with a solvent resistant spray to protect it from the harsh effects of the excess solvent. Blend the silicone rubber with the solvent to get a thin mix. This will be flowy and take considerable time to cure. Once semi-done, demold quickly and leave it to dry.

The solvent evaporates to gradually shrink the cast in a proportionate manner all over. While the level of shrinkage depends on the amount of solvent added, it generally takes 3 days for the cast to reduce to 85% of the original. Leaving it for 7 days will further shrink the size to about 80%. You can make successive casts to get further shrinkage.

Some artists substitute the solvent with odorless mineral spirits that again tend to evaporate, leading to proportionate shrinkage.

Similarly, some water based urethanes are also available that successfully reduce the size of a cast to scale.

Mold making and casting knows no boundaries. Even sand particles can be bonded with sodium silicate to make sand molds that are later used for making metal castings. This compound is made by mixing sodium carbonate and silicon dioxide.

And if you are thinking about where to source this sodium silicate or water glass, it is available on the EnvironMolds website. ArtMolds Sodium Silicate is available as an aqueous solution in 1 pint, 1 gallon and 5 gallon bottles. This additive is multi-purpose and can be used for several other applications too. Such as:

•    It is commonly used by artists to create an instant antique patina on ceramics and pots. The antique finish coating looks natural and believable.

•    It can be used as an economical deflocculant for clay. As the compound thins the clay, slips can be made with minimum water content. However, you have to be careful about the proportion as after a point water glass starts flocculating the same clay!

•    It works as a high temperature adhesive. A thin layer can dry to effectively bond different materials like metals, paper, plaster, ceramics, glass, fiberglass and even refractory materials.

•    The excellent sealing and bonding properties work very well for concrete, plaster and gypsum surfaces. The chemical reacts with the concrete to form a permanent bond. This makes the surface stronger, denser, wearable and water resistant too. The same function can be applied for sealing plaster molds and casts very effectively.

containers to vibrating tables, vacuum pumps and chambers. There are different types of mounts and even

Liquid latex rubber is regularly used for making latex mask as well as creating special effects such as wrinkles and scars. While liquid latex is quite easy to use and lasts long, any regular user will vouch for the fact that the rubber has a distinctive smell, especially when a fresh box is opened.

Liquid latex does bear the characteristic smell of alcohol which is primarily due to its ammonia content. A tiny amount of ammonia is added to liquid latex rubber to increase its shelf life as well as to control its pH level. These ammonia fumes escape when a box is opened and should not be deeply inhaled. In fact, too much of sniffing can burn the nose, throat and even the respiratory tract.

This is why liquid latex should be used to make a latex mask in a well-ventilated area. Those who are especially sensitive to the smell should use a face mask. The good news is that the smell disappears as the liquid latex dries!

Similarly, the ammonia fumes can also irritate the eyes and skin at times. Therefore, it is advisable to air the liquid latex for some time before applying it on the skin or face for special effects. 

In sum, proper handling and use is essential for liquid latex just like any other product. Use it with care to get best results always!

While wax or clay modeling materials are used as it is, most other mold making and casting materials feature two components – generally a base and a catalyst - which have to be mixed together before use. Some materials need to be mixed with water (like plaster or alginate). In either case, you have to follow the prescribed mix ratio (can be by weight or volume) to the letter, to get the proper consistency, curing and finish.

In clay modeling making an accurate mix in the specified ratio is not the only thing that is important. The two parts that are being combined also need to be mixed thoroughly to get the desired effects. In fact, many a times the two different components are of different colors and can cause an undesirable marbled effect if not mixed properly. In some cases, it can also turn out lumpy and quite unusable.

Careful and comprehensive mixing alone will ensure a uniform color and consistency throughout. Following are a few tips on the same:

•    Large volumes often end up inadequately mixed and quite ineffectual. This is why professional artists often prefer to mix small quantities of their mold making and casting materials at a time.

•    Use a firm grip and a steady hand to mix in circular motions.

•    Keep scraping the sides and bottom of the container you are mixing in so that nothing remains settled anywhere. To avoid this, many artists even pour the mixture into another container and mix again.

•    Always over mix rather than under mix!

Life casting models often get put off by hair tangles and painful tugs during demolding. No matter how much baby oil or even petroleum jelly the artist slathers on the model’s head and body, the latter’s hair still ends up getting entrapped in the body mold. In fact, life casting artists often complain that their models refuse to repeat the experience and do not come back for further assignments. 

Clay modeling or resin casting is easier as it does not involve the live human body, but life casting requires careful preparation with an effective release agent. EnvironMolds offers an excellent product called MoldEZ Hair and Mold Release. This is water soluble and washes off easily at one go without tangling the hair at all!

It’s easy to apply MoldEZ – work generous amounts into the hair on the head, underarms or pubic area right from the root to the tips before combing them into place. You can also apply this water-based release cream on all fine body hair. The mold will come off easily from the body without pulling on the hair unnecessarily. MoldEZ is made completely from natural ingredients, is safe for the skin and can be washed out very easily with water.

Apart from this, MoldEZ also comes in handy as an adhesive for binding the alginate mold to the mother mold. Apply it generously all over the separated area. You can also use it to fill any pin holes in the alginate molds prior to casting.

Life casting artists are generally familiar with the tricks of their trade. They have honed their skills to perfection – from making a mold, demolding and casting to also finishing the final sculpture so that it’s ready to display in all its magnificence.

However, life casting requires an artist to work with a living and breathing model, and alas, many people falter in this aspect. The problem gets compounded as both the quality of your model and his or her cooperation is vital for the success of your life casting project.

Therefore, finding and hiring the right model (and offering proper compensation) is half the battle won. There are various sources for locating models that do not have any inhibitions against life casting. At this stage, remember to protect your interests with an appropriate model release form.

Now comes the task of preparing the model for what lies ahead. New models need to be carefully informed about the life casting procedures and applications. Even experienced ones need to get familiar with your techniques and requirements.

Discuss the pose you have in mind and try it out to ensure that the model is comfortable. There is no harm in trying out different postures before settling on one where the model feels most relaxed. Always remember that the quality of your final life cast completely depends on how comfortable the model feels when you are making a mold!