Difference between Poured Block and Blanket Molds

Posted by EnvironMolds , Labels: , , , , , Monday, September 12, 2022 11:58 PM

The uses of silicone rubber across mold making and casting are too many to list. It can be used to make both block and blanket molds. Find out how to make these poured molds using silicone rubber.

Silicone rubber is an inherently versatile material which lends itself well to various applications in both mold making and casting. When it comes to mold making, both the poured block and poured blanket molds can be made using silicone rubber. Let us take a look at both these techniques:
 

Poured block mold – This is considered the simplest method for making a mold. All it requires is making a containment area or a mold box. For this, the model is first secured to a flat base and the edges are sealed with clay or glue. The walls of the box can be made using particle board, plywood, PVC pipes, etc. These walls will have to be secured together as well as to the bottom of the box before sealing the interior edges and corners to prevent leakage of any kind. Alternatively, the walls can be fashioned with clay itself.

Once the mold box is ready, making the mold is as easy as simply pouring the mixed silicone rubber into the box till it completely covers the model and then some more. This should be done from a corner while avoiding pouring directly over the model. Let it cure proper before demolding by dismantling the mold box and prying the mold loose. The mold will be ready for casting.

This technique does require a lot of rubber but is preferred for its simplicity.

 

Poured blanket molds – This is a more complicated process as it requires constructing a mold shell over the model which will take some practice. Here also the model is first secured to a base. Then it is covered with plastic wrap before applying clay to about half inch thickness. This should be uniform and fill all undercuts in the model. The clay is extended to form a flange and a pour hole is also needed.

A thickened mixture of polyurethane resin is applied over the clay and legs are added that will serve to hold and level the mold later on. Holes are drilled evenly throughout the plastic flange that will help in repositioning and screwing later.

Once cured, the mold shell is demolded and the clay is removed from inside. The model is again glued to the board and the plastic shell is repositioned over it by aligning the holes before securing it to the base with screws. Sealing the edges with clay will prevent leakage.

Mixed silicone rubber is poured inside through the hole at the top. This will cure to form a mold in place of the clay. The mold shell is removed and he edges of the silicone mold are loosened for demolding it from the model. When casting, the mold has to be placed in the shell mold again.

It is clear that this process may be complicated, but will require much less mold making material. The final casting will be easier to demold too as the poured blanket molds are thin and flexible.

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Life Casting Finds Diverse Applications

Posted by EnvironMolds , Labels: , , , , , Thursday, September 1, 2022 2:57 AM

Wondering who will need a life cast and what purpose will it serve? Well, you will be surprised to know the multitude of applications of life casting right from memorabilia to special effects and more.

Life casting is a three-dimensional reproduction of any part of the live human body. It not just captures the shape and structure, but also minute details like fine body hair, skin texture, fingerprints and even the pores on the skin. This is a permanent and durable copy that lends itself well to varied uses.
 


  • Parents love to preserve a memory of the tiny hands and feet of their newborn baby with a life cast.
  • Many people like to get a life cast of their face or other preferred body part to immortalize their appearance in the best manner possible. While face casting is most common, people also get life casts of their hands, torso, hips, breasts, abdomen or even the full body. Pregnant women often opt for a belly casting as a lovely keepsake of this momentous part of their life. Group castings of hands are common with friends and families.
  • The life casting technique is also used for making busts of national figures and other famous people. It is often used for making human sculptures and wax statues too.
  • Law enforcement agencies use life casting for forensic work like fingerprints.
  • Life casting fits in perfectly for medical applications like making prosthetic body parts for amputees. The missing hand, leg, finger or toe is accurately reproduced with life casting, thus ensuring a perfect fit.
  • It also finds other applications in the medical field, like creating medical training aids.
  • Museum preservation also relies on life casting for various tasks.
  • When it comes to special effects and prosthetic makeup, the first step always involves making a life cast of the face, torso, arm or other body part. The changes to the nose, ears, eyes, cheeks, hands, fingers or feet are sculpted on to the life cast. As this is customized specially for the actor, it will ensure a perfect fit that will be comfortable as well as allow him/her to breathe, emote and move normally. Given the precise conformity with the desired area of the body down to the skin texture, it will ensure a seamless blend with the natural features of the actor. The special effects also look extremely realistic and believable, a far cry from the unnatural-appearing computer generated options.
  • Life casting also makes an interesting and enjoyable art activity for students, parties and the like. Special kits are available with all the requisite materials and supplies which can make for an afternoon of creativity and fun.

When it comes to sourcing quality materials and other requisites for making a life cast, the best source is EnvironMolds. It even stocks kits – like the ever popular Face EZ Cast Kit – an all-in-one answer to attempting a life cast for beginners. The art studio is passionate about promoting life casting and is willing to provide tips and assistance for making life casts.
 

 

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What You Need to Know About Latex Casting Rubber

Posted by EnvironMolds , Labels: , , , , , Thursday, August 11, 2022 4:29 AM

Latex rubber is fun to use and lends itself well to varied projects. It can be used by beginners as well as experienced artists. It is fun to play around with the rubber with unending creative possibilities.

Liquid latex rubber can be split into two categories – mold making and casting rubber formulae. While the purpose is obvious from the names, it should be noted that liquid latex casting rubbers are always less viscous than the mold making ones. Therefore, they are preferred for making props, masks and other theatrical work.

As this category of rubber is more fluid, making the cast is as easy as pouring the material into the mold and letting it sit for some time before pouring it out again. This forms a thin skin inside the mold – the perfect way to make stretchable masks, props and other thin rubber items. RD-407 Mask Making and Casting Latex is the preferred product for such applications.

The same latex can be applied on the skin to create varying kinds of special effects. It will dry quickly to form a second skin of sorts, making it perfect for creating gashes, wounds, cuts and even horrifying effects.


Working with latex rubber


Latex rubber compounds are very easy to use as they do not require any mixing or other preparations. Application is direct and simple and the molds/casts capture excellent details to create an exact reproduction.

Latex casts are inherently flexible, more so than the casting formulations. However, the degree of flexibility of the latex cast can be controlled by adding an appropriate filler. RubRfil Latex Mold Rubber Filler And Extender is an excellent product that can make the latex cast turn out to be very flexible or very hard depending on the combination. The following proportions are suggested to get varying results:

  • 1 part latex to 1/2 part RubRfil - very flexible
  • 1 part latex to 1 part RubRfil– flexible
  • 1 part latex to 1 1/2 part RubRfil - medium flexibility
  • 1 part latex to 2 1/2 part RubRfil - very hard

The versatility of latex casting rubber comes to the fore when it is used for dipping and coating purposes. Fabrics can be dipped in liquid latex to make them waterproof. The same coating can also insulate tools from electric hazards. Apart from the protection, the coat also improves grip and comfort during usage.

Latex rubber usually has a transparent or white finish. It can be colored using special paints and dyes as the regular ones tend to chip and crack easily. These can be used intrinsically by mixing in the latex rubber or be painted on the cured latex surface. Varying shades are available.

When it comes to storing the liquid latex casting rubbers, both the material and the molds/casts have a long life and extended durability. However, keep in mind that liquid latex has a fair amount of alcohol mixed in it and should be handled with care. It should be stored in airtight containers and kept away from sunlight.
 

 

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What You Need for Mold Making and Casting

Posted by EnvironMolds , Labels: , , , , Friday, July 22, 2022 2:16 AM

Making molds and casts involves a range of materials, supplies and equipment. Following is a look at the different items that should be kept at hand before beginning a mold making or casting project.

Mold making and casting are intricate arts that require different materials, supplies, tools and equipment. A lot of details are involved in these processes and it calls for careful and precise usage of the procedures as well.

To begin with, there is a choice of a variety of materials like clay, wax, plaster, alginate, liquid latex rubber, silicone rubber, polyurethane resins and more. The selection depends on the technique, artist’s dexterity and preference. The common tools and supplies range from brushes, spatulas, gloves and containers to knives, rasps, scalpels, pliers, calipers, etc. In case the materials involve an element of risk to the artist, it is advisable to wear protective equipment like gloves, goggles, mask and coat. Some even use a respirator to prevent inhalation.
 
The mold making usually starts with a mold box and a base plate. The master model is either placed in the mold container or secured to the base with clay or a suitable adhesive. A sealant may be required if the model has holes or happens to be porous. Applying a thin coat of an appropriate release agent is usually recommended as it will help in easy demolding.

Again, depending on the mold making material, it may have to be degassed using a vibrating table, pressure pot or vacuum chamber with pump. This will eliminate air pockets in the material which show up as unsightly bubbles in the mold.

Once the mold has cured properly, the demolding process can involve cutting the mold with a sharp knife, scalpel or using other tools to extract the model from the mold. The mold is smoothened using certain specific tools before it is ready for casting.

In case the mold is made in two or more parts, it will require placing keys that facilitate an easy coming together of the mold parts. If the mold is very flexible, it may even have to be reinforced with a shell mold that is generally made with plater bandages.

The casting process usually begins with applying a release agent on all the surfaces of the mold to ensure easy demolding later. The material may also have to be degassed before pouring into the mold. Once the cast has cured, it is extracted using tools and finished as required.

The cast can even be painted to create the desired effect. Some rubbers and resins require special paints and dyes as the regular ones are not compatible with these materials.

Last but not the least; all the materials, supplies and other requirements – like say, latex rubber, silicone rubber, scalpel, mixer and vacuum chamber – should always be sourced from a established and reliable source to ensure that everything is of top quality and will work as expected. This will ensure best results in the mold making and casting.

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The Various Facets of Sodium Silicate

Posted by EnvironMolds , Labels: , , , , Wednesday, July 13, 2022 4:24 AM

The compound sodium silicate has many applications. While industry folks are familiar with sand molded metal castings, artists prefer to use it to deflocculate clay slip and create antique finishes on ceramics.

Sodium silicate is a simple inorganic sodium salt that is also called water glass. It comes in a flaked solid or powdered form which is dissolved in water to make an alkaline solution.

This silicate lends itself well to a host of uses that are quite varied in nature. Consider this – sodium silicate is equally effective in both treatment of waste water and preservation of foods. It is used in paper and detergents as well.

The same formula can also be used to reduce porosity in concrete, stucco and plaster. Applying a thin coat on masonry surfaces after they have cured will seal the surface, thus minimizing water penetration. In fact, sodium silicate displays excellent physical and chemical properties that are useful in bonding and coating applications. It will dry to form a tough, tightly adhering inorganic bond for metals, ceramics, glass, etc.

Apart from this, sodium silicate works as a deflocculant for clay slips and can also render an instant antique finish on ceramic surfaces.

But the most common and useful application is in metal or foundry mold making applications. A blend of sand and sodium silicate is used to make the mold. the mixture is packed into a core box of the desired shape and wires or rods are inserted as required for support. This is exposed to carbondioxide gas from a low pressure source or esters which induces a chemical reaction that will solidify the core. Once it has solidified, it is ready for use.

These molds are used in the iron, steel and cast iron industry. Molten metal is poured in the sand molds to make the casts.


Where to buy?


EnvironMolds is a veritable powerhouse supplier in the world of arts and crafts. The website is packed with a broad range of materials, supplies, tools and equipment for making molds, casts and life casts. All products are from leading brands with top quality, reasonable prices and environment safety being the differentiating factor across the board.

The repository includes sodium silicate from the inhouse brand of Artmolds. This inorganic multipurpose additive is formulated in aqueous form and can be used for different purposes. It is low cost, odorless, non-toxic, moisture-resistant and non-flammable too. As it is made from sand and alkali, it proves to be ecologically harmless in fresh water environments too.

However, it can irritate or burn the skin and eyes on contact. Observe safety precautions like wearing splash-proof goggles, rubber gloves and coveralls.

The company further advises that the product should be stored in a cool, dry, well-ventilated area, removed from oxidizing agents, acids, active metals, heat or ignition sources and foodstuffs. It should be protected from physical damage and sealed properly when not in use. If properly stored, unopened containers can be good indefinitely.

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The Molding and Casting Approach to Making Replicas

Posted by EnvironMolds , Labels: , , , , Friday, July 1, 2022 1:43 AM

Mold making and casting together form an efficient process for reproducing almost anything. There are clear differences between the two techniques and artists should know the ins and outs of both.

The most common method of making an exact three-dimensional replica of an object is molding and casting. In fact, most of the everyday items that people use in their homes and offices have undergone the molding and casting process.

Mold making


The mold forms the first step of making the replica. This is a hollow cavity of the shape of the model or master that is to be reproduced. It is also considered as a negative of the desired object.

Molds can be made with different materials and there are various techniques for the same. While anything like clay, wax, resin, silicone rubber, polyurethane rubber or thermoset mold rubber will lend itself well for making molds, the general consensus is that molds should be made with flexible materials as this makes it easier to demold the cast.

When working on molds, the mold making material has to be mixed properly and may even require a vacuum pump with vacuum chamber to ensure that it is free of air bubbles.

The best part about molds is that most of them are reusable and can be used for making multiple casts. But keep in mind that while some molds lose their shape quickly and are good for single castings only, others will also have a limited shelf life and will start to deteriorate with time.


Casting


While the mold is the first stage, casting forms the final stage that delivers the finished replica of the original model. A casting is usually made by pouring the casting material into the hollow mold. It is allowed to cure and then extracted to obtain the final product. This can be sanded, painted or finished as desired.

Here again, there are different techniques for casting and varied materials lend themselves well for the casting process. Yet, in general, it is better to use materials that cure to a hard form as this ensures efficiency in the process and durability in the final cast. The materials that are commonly used are plaster, gypsum, concrete and polyurethane resins apart from an assortment of rubbers. A vacuum chamber may again be required – especially for rubbers – to ensure that the cast is smooth and blemish free.

As the casting is the finished product, it obviously cannot be used in the process again and again. However, at times, casts are used to make secondary molds as they already hold the desired shape.

In sum, mold making and casting are used in conjunction to make duplicates of varied items. The have their own inherent characteristics and artists have to familiarize themselves with all the features before attempting to use them. These processes can also be used for other purposes like mask making and doll reborning. Life casting also draws on this to make reproductions of the live human body!

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How to Choose a Mold Material Made Easy

Posted by EnvironMolds , Labels: , , Thursday, June 16, 2022 11:36 PM

 

Making a mold is a complex proposition that involves various factors right from the technique to the choice of material. Indeed, the material used to make the mold – be it clay, plaster, alginate, resin, latex rubber, silicone rubber, polyurethane rubber, etc. - will have a bearing on everything related to the quality, resilience, durability and even the very usability of the mold.

While different mold makers have their own specific criteria for choosing a mold material, there are some basic aspects that have to be kept in mind, such as:

  • Consider the material of the model. In general, it is better to pick a material that can be used on stone, wood, glass, metal, wax, plaster, ceramic or clay. In case of a body mold, the material should be safe for using on the skin, capture fine details and cure quickly too.
  • Take the characteristics of the model into consideration. Is the pattern simple with no undercuts or does it have a complex shape with deep undercuts? In case of a vertical surface or large/immovable objects, the model making material should be such that it can be applied on the details where it is without running off or needing to be thickened.
  • Compatibility with the casting material also has to be taken into account. Certain mold making materials may not be suitable for casting specific types of resins, rubbers or metals.
  • There are other aspects that warrant a closer look before closing in on an option – like catalyst, curing agent, working time and cure time at room temperature, etc. While at it, consider if the pot time and demolding time can be modified if needed.
  • Focus on the specific performance objectives expected from the mold/mold making material in terms of viscosity, appearance, durability, resilience, shore hardness, tensile strength, flexibility, shrinkage, tear strength, reusability and more.
  • In case of a flexible mold, a reinforcing shell mold will be required and the material compatibility factors will come into play again.
  • Consider the tools and equipment requirements of particular materials to ensure that the studio is prepped to work as required.
  • Take the mold features into account. For instance, a silicone mold varies in many aspects to a resin mold which will again be miles apart from a clay one.

Generally speaking, look for materials that are easy to use, can reproduce intricate details and are known to hold severe undercuts. It will be better if they also feature excellent release characteristics with customizable working times and cure rates. They should be flexible enough to tolerate the stress of demolding and be able to adapt to a range of service temperatures. Good resistance to chemicals and ability to withstand wear and tear with repeated use will also be helpful.

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