Silicone Rubber - Different Faces and Usage

Posted by EnvironMolds , Labels: , , , , Tuesday, April 13, 2021 6:38 AM

Silicone rubber is a versatile material that is used for different purposes in both the art and manufacturing world. It displays many useful properties and comes in a few different types too.

Silicone rubber is a popular compound that enjoys widespread patronage across industries and applications. It is commonly used for bonding, sealing, potting, encapsulation, coating, mold making and casting works.

The main benefit is that silicone rubber molds that can be used for manufacturing different types of technical and mechanical parts for industry and medical devices. Apart from molds, silicone rubber is also used as a release agent, adhesive or the base material for the cast. It also functions well in the potting of electronic components in high-tech industrial and scientific equipment.

Artists normally use the rubber to make molds for toys, candles, soaps, food and baking containers apart from special effects. There is a special variety of silicone rubber that is safe for the skin and is used to make body molds.

The same rubber can be used to make casts too and is the material of choice for mask making and doll reborning.


Getting to know Silicone Rubber


RTV silicone rubber is commonly used for molding and casting projects. It delivers various useful properties like ease of use, flexible, tough, durable and tear resistant. This versatile material can reproduce almost anything without damaging the surface of the model. What’s more, the excellent mechanical properties and low surface tension enable it to replicate the mold without losing any of intricacies of the original - the minutest of details will be captured in the mold even down to the skin pores and fingerprints. It can even be cast in abrasive materials.

Silicone rubber formulas are remarkably stable in a wide temperature range and prove to be non-flammable and non-combustible. There is a good level of thermal conductivity too.

The room temperature vulcanizing rubber comes as a 2-part formula – one is the liquid base and the other is the catalyst. They have to be mixed in the specified proportion which can vary from formula to formula. The catalyst will react with the base to deliver the intended properties. It can even be customized to produce the required degree of viscosity and adherence along with varying mechanical, chemical or temperature resistance characteristics.

The rubber comes in two different types – addition cure and condensation cure. The primary difference is in the catalyst - Addition cure silicones use a platinum-based catalyst (usually 10%) while condensation cure silicones need a tin-based catalyst (usually 5%). They have different characteristics and usage and most importantly, are not compatible with each other.

EnvironMolds offers a broad range of materials, supplies, tools and equipment that include both silicone mold and casting rubbers. There are different formulae options to suit varying needs and preferences, like MoldRite 25 Silicone - Classic Mold Making Silicone, BluMold RTV Silicone, 5-Minute Mold Putty for Faster Mold Making, Food Safe Silicone -- BakeSil FDA Approved, LifeRite Skin Safe Silicone for Life Casting and SkinRite 10 Translucent Special F/X Silicone.

0 Comments

The Ins and Outs of Latex Rubber

Posted by EnvironMolds , Labels: , , , , , Wednesday, March 31, 2021 4:29 AM

Latex rubber is an artist’s weapon that can be wielded in varying manners. The properties and versatility of liquid latex rubber are to be experienced to be believed. Let’s find out more about this….

Liquid latex rubber is a versatile product that lends itself well to varied applications. The wonderful part about the rubber is that it is suitable for making both molds and casts. Changing the viscosity will change the application – latex molds require more thick and viscous formulations than casts. The degree of flexibility of the latex can be further controlled by adding an appropriate filler during the casting process.


Latex mold rubber is commonly used for mold making as it is economical, durable and easy to use. The molds will be tough, tear resistant and can be reused multiple times. They are used to cast plaster, polyester resin, urethane and even abrasive materials like concrete.

On the other hand, the casting variant of latex rubber is used for making hollow molded rubber articles like toys, balls, props and even display articles. It enjoys great patronage for making masks, puppet heads and even special effects like wrinkles, scars and gashes for theatrical work.

Latex rubber can be brushed, sprayed, poured or dipped for making the molds and casts. Brushing requires successive coats and sufficient time should be allowed for drying between each coat. This process is continued till the desired thickness is obtained. Spraying will also involve a similar process.

Latex is usually cast in plaster molds because of the porous nature of plaster. When the rubber is poured into the mold, the plaster sucks the water out and leaves a thin latex skin behind. Slip latex casting is a commonly preferred method as it is comparatively easy and does not leave any brush marks either.

When it comes to demolding the latex mold or cast, an easy trick is to dust the latex with talcum powder before peeling it off slowly. The powder will keep the fresh latex from sticking to itself. The latex mold will need to be supported before casting so that the flexible rubber can retain its shape.

Latex rubber is also used to form a protective coat on different items. The latex coat can make fabrics waterproof. It can also form a protective covering on tools that will provide a sound and comfortable grip even while insulating them against electrical hazards.

The most common use of latex rubber is for making a latex mask. This can be used for special effects in movies or even a fun element for Halloween and other occasions. It is usually cast in a face mold made of plaster bandages and then the desired characteristics are built on it step by step.

Other tips to keep in mind when working with latex rubber is that it contains a good amount of alcohol. Proper ventilation is required and do not inhale it too deeply or frequently. Similarly, the rubber will become unusable if frozen. Store it carefully in the winter months of the year.

0 Comments

The Fiber-Reinforced Version of Alginate

Posted by EnvironMolds , Labels: , , , , , Saturday, March 13, 2021 3:35 AM

There are alginates and then there is fiber-reinforced alginate. This comes with greater tear strength and delayed shrinkage which makes it ideal for larger life castings as well as for special effects works.

Alginate is the material of choice for making body molds. This is a natural compound that is actually derived from seaweed and is used to make dental impressions. Its quick setting and skin safe properties make it suitable for using as the base material for life casting.


A variation of the regular alginate – with a slower set time than the dental formula – is used for making body molds. This alginate is mixed with water and the paste is applied directly on the skin. It sets quickly while capturing a perfect negative impression of the body part – be it face, hand, foot, torso, abdomen or even full body. A good quality alginate, when used properly, it will capture all the fine details and indentations of the body surface down to the fingerprints as well. Everything can then be reproduced in clear detail in the life cast.

Now alginate comes in different varieties to suit diverse requirements. The traditional formula is in the form of a white powder that contains silica and offers a firm set. Yet, it needs to be reinforced with a shell mold as the alginate will not be able to retain its shape on its own after demolding.

In case artists want to steer clear of silica formulas, there are silica-free alginates that offer a softer set and are, therefore, gentler on the skin. This is especially favored when making life casts of a baby’s hands or feet.

Both these categories of alginates come in variants of slow set, regular set and fast set, to suit varying dexterity and applications. For instance, the slower setting formulas prove to be very useful when making molds of the torso or other large body parts. The slower set ones are again preferred when working with infants.

The best type of alginate is the fiber-reinforced alginate – like FiberGel alginate. This contains fiber which not only helps enhance the tear resistance and strength, but also increases the alginate’s capacity to hold moisture. It also serves to delay the shrinkage of the alginate mold, thus giving more time for the casting process.

Therefore, FiberGel is the best choice for larger molds and actually, all life castings. In fact, FiberGel E F/X Grade Alginate (available on the EnvironMolds website, https://www.artmolds.com) is specially formulated for professional high-production, high-end detailed E F/X work.

This FiberGel comes with a patent pending duo fiber matrix system that has been independently tested 40% stronger than the best options in the market.

What’s more, the fiber content also serves to prevent runs and drips. The alginate mix (when made using the prescribed ratio of powder and water) will stay where you put it. This makes it suitable for working on vertical surfaces too. The molds also stay soft and flexible far beyond normal alginates, thus extending the window for casting times without any loss of detail.
 


0 Comments

Correcting Mistakes in Plaster Life Casts

Posted by EnvironMolds , Labels: , , , , , Tuesday, March 2, 2021 11:12 PM

Errors are bound to happen at different stages of the body casting and life casting process. Here we take a look at the problems that can surface in a plaster life cast and how to correct some of them.


Life casting begins with capturing a mold of the human body and ends with a finished cast that is an exact reproduction of the model. The body mold is usually made using alginate or skin-safe silicone rubber while plaster is preferred for the life cast. The final piece is usually mounted and finished with a brass name plate.


Now there is a lot that can go wrong during the body casting and life casting process. While a lot has been written about working with alginate, let us take a look at the possible complications that can arise during the plaster casting:

Air bubbles – Like any other mold making or casting material, plaster also has a propensity to trap air that can show up as unsightly bubbles on the surface of the cast. Life casting artists are always advised to pour the plaster slowly and carefully in a thin stream from a corner of the mold. Tilting the plaster-filled body mold a bit or tapping the sides will also cause the trapped air to rise to the top and can be burst easily. However, if some bubbles still happen to appear on the life cast, they can be smoothed out with the thumb, back of a spoon or by applying some water. Some artists pop them gently with a knife and then fill the hole with more plaster. Rubbing with sandpaper will help level out the final cast.

Broken fingers – Features like nose and fingers are small and delicate when compared to the entire life cast. They are very likely to break during the demolding process – it could be that the plaster has not set enough or the artist has applied too much pressure or is working in a hasty manner. The broken part can be refastened by wetting both the edges and applying some plaster. Reposition the piece and hold it in place till it sets properly. The joint can be smoothed with a wet finger or some thin plaster.

Similarly, other distortions or squashed features can also be corrected with some careful resculpting. However, it is always better to make the corrections in the body mold itself as far as possible rather than risk disfiguring the life cast.

Rough surface of the casting – At times, the plaster surface of the casting may seem coarse and bumpy in places. This can happen due to various reasons like skewed ratio or improper mixing of the plaster. Either way, the best recourse it to smooth out the surface with sandpaper.

These techniques will work for minor errors and corrections. In case of a major blunder, it is better to redo the life cast rather than keep trying to correct an inherently flawed or inadequate piece.

And when the perfect piece is ready, it can be mounted on a marble or wooden base and finished with customized brass name plates engraved for that wonderful gallery finish!

0 Comments

Precautions for Using Sodium Silicate

Posted by EnvironMolds , Labels: , , , , Wednesday, February 10, 2021 12:28 AM

Sodium silicate is an extremely useful material that lends itself to varied uses; but it needs to be handled with care and caution. In fact, it comes with its own set of safety and handling information.

Sodium silicate is formed from the reaction of sodium carbonate and silicon dioxide in a molten state. This universal compound finds multiple uses across diverse platforms. In the world of art, it is commonly used to give an antique finish to ceramic creations. It is also used as a clay slip defflocculant apart from aiding in making sand molds for metal castings.

The same sodium silicate serves excellent bonding and coating applications as well. The high-temperature can form a tight bond between any two materials; it also works to help harden cardboard cartons or applying labels. Also known as water glass, it is used to seal plaster, gypsum and stucco surfaces thus making them impermeable and water resistant. The same property comes in handy for sealing cracks in concrete floors, sidewalks and driveways.

The industry usage of sodium silicate ranges from cements, passive fire protection and refractories to textile and lumber processing and automobiles.



Care and caution


Like most other compounds, sodium silicate needs to be handled carefully. While it is essentially non-toxic, the solution can still irritate or even burn the skin and eyes on contact. Inhalation should also be kept to a minimum.

Therefore, users should make it a point to wear rubber or PVC gloves and overalls when using sodium silicate to make sand molded castings, clay slips or other usage. Wearing splash-proof goggles and rubber boots is also recommended, especially when using large quantities or where heavy contamination is likely.

These are the general precautions that should be carefully adhered. In addition, it is always advisable to vigilantly read the product label and get a handle on the safety measures that will be duly mentioned on the packaging. Following safe work practices will prevent untoward injuries or accidents when working with the compound.

Where to buy?


EnvironMolds offers a complete range of materials, supplies and equipment for making molds, casts and life casts. It is the favorite art store of all kinds of artists as they can find whatever they need and then some more.

ArtMolds Sodium Silicate is just one of the varied components on its broad menu of items that will be handy in the art studio. It is available in 1 pint, 1 gallon and 5 gallon packages. And it goes without saying that like all the other products, this water glass compound is also of top quality and offered at a reasonable price. The regular properties of sodium silicate also hold good – it is odorless, non-toxic moisture resistant, non-flammable and resistant to temperatures up to 3000° F.

The label on the bottle of aqueous solution obviously specifies the safety precautions to be observed while using the sodium silicate. In addition to this, the company website, https://www.artmolds.com also provides supplementary Material Safety Data Sheets for all its products as further guidance.

0 Comments

Varied Uses of Plaster

Posted by EnvironMolds , Labels: , , , , Wednesday, January 27, 2021 6:24 AM

 Plaster is a simple powder that is mixed with water before use. The material cures slowly to capture the shape in a solid form. This plaster can be used in varied ways to suit different purposes in the arts.

Plaster is a humble white powder made with a combination of lime or gypsum with sand and water. It is mixed with water to form a stiff paste before application. It dries to a solid form in some time. It is usually known as plaster of Paris as the gypsum was mined in abundant quantities in Paris.

The most common use of plaster mix is to coat walls and partitions to make the surface smooth. It is used to make false ceilings apart from stucco work and rendering. It also lends itself well for decorative architectural moldings like cornices and corbels.

Plaster is also used in the medical field to make casts for immobilizing broken bones and supporting the fracture till the bones can set properly once again.

A variation of the regular plaster also finds its way into the world of mold making and casting. This is different from the regular plaster of Paris which tends to become chalky and flaky over time, does not hold detail well and is hydroscopic in nature.

The art variant of plaster is harder which allows it to capture crisp details and set to a smooth solid. Yet it can be carved or tooled as desired. This is used in mold making and latex slush molds while plaster bandages are used to make shell molds or even form molds.

Plaster can be used for general mold making, but care should be taken as the material tends to emit heat due to the chemical reaction. Therefore, it can damage the product or harm the model when applied directly on the body. Some people have been known to get burns when plaster is used in large volumes!

A better application of plaster is for making the life castings. The plaster mix is poured into the alginate or silicone body mold and allowed to cure. After demolding, it turns out a bright white life cast that is a spitting replica of the original body part. It can then be finished as required before being put up for display.

Plaster is coated over gauze to form plaster bandages that can be used to make shell or mother molds. The wet bandages are smoothed out over alginate or rubber molds. They dry to a rigid form and thus lend the required stiffness to the flexible molds that would otherwise flop over themselves making it difficult to cast properly. The same bandages can also be used on the skin to make rough body part molds like the abdomen as they do not have much detail. Artists also use the same technique for making a face mold for making masks.

EnvironMolds offers a range of plaster options for pottery, casting and the ever-popular Plaster of Paris bandages.
 

0 Comments

Difference Between Plastic and Silicone Molds

Posted by EnvironMolds , Labels: , , , , Monday, January 18, 2021 9:05 AM

Which is better – plastic or silicone molds for making castings of resins and other materials? Both options come with their own pros and cons. Generally, silicone ones are preferred by professionals.

The technique of making a cast begins with a mold. The casting artist will either make a mold or use a ready mold for making the cast. The casting material is usually poured into the mold and allowed to set before being demolded. Once it has cured properly, it is finished and is ready for use. How to make a mold for the casting is another story for another day.



However, here we shall take a look at the type of molds to be used for making a cast. Let’s consider plastic and silicone molds for instance.

Plastic molds usually have a lot going for them. They are easily available in the market in a variety of shapes and sizes. They are flexible, reusable and quite inexpensive at that. Being quite easy to work with, these molds are considered apt for novices stepping into the world of casting. Even if the molds get damaged, they can be easily replaced or even discarded if someone loses interest in the hobby.

On the other hand, silicone rubber molds are more sophisticated and top quality molds that are preferred by professional casting artists around the world. They may seem like a substantial investment initially, but this does pay off in more ways than one.

The biggest thing working in favor of silicone molds is that they can be customized as desired. The mold maker can make single or two part molds of any item that is to be replicated as a cast. However, making a plastic mold calls for specialized techniques and equipment for working on vacuum forming sheet plastic around a template. Therefore, making casts from plastic molds can be limiting based on the ready molds available.

Then again, casts made in plastic molds do not turn out glossy enough. The molds tend to get scratches easily, which also affects the quality of the castings. The surface that is touching the mold will have to be recoated with either the casting material or a sealer to make it shiny. On the other hand, castings from silicone molds have a smooth and shiny finish that is pleasing to the eye.

These molds also lend themselves well for making complex castings. Demolding is especially easy even for complicated shapes as silicone does not stick to anything except itself. It should be kept in mind that silicone molds are extremely durable, but only as long as they are cleaned and stored properly.

EnvironMolds offers a range of materials, supplies and equipment including a great selection of high quality silicone rubber formulas that are suitable for both mold making and casting. Indeed, most silicone mold rubbers can double up as casting rubbers too. However, artists should bear in mind that silicone rubber should never be cast in silicone molds as they will tend to stick to each other.

0 Comments
Subscribe to: Posts (Atom)