Using a Release Agent in Mold Making and Casting

Posted by EnvironMolds , Labels: , , , , , Monday, January 24, 2022 3:47 AM

Before making a mold or cast, the model or mold has to be prepped for the job. This includes applying a coat of release agent as this will aid in easy demolding. The same goes for body molds as well.

There are many intricate minutiae involved in making a mold or cast. It is not just about the choice of material or technique; the artist also has to consider various other factors and requirements that can affect everything from the details captured in the mold to the quality of the final cast.

One such detail is the use of a release agent. The name is self-explanatory – a release agent keeps the mold from sticking to the model or the cast from adhering to the mold, thus facilitating easy demolding. Household products like petroleum jelly or paraffin wax can serve well as a release agent, however, for best results, it is advisable to use a professional mold release.

Keep in mind that there are certain materials like silicone rubber that do not stick to anything except itself. Therefore, it is commonly perceived that a release agent is not required. However, it is still better to use one as this will significantly increase mold life!

How to use?


Before applying the release agent, first clean the model or mold properly to prevent any kind of unevenness in the mold or cast later on. The model or mold should be sealed if needed and allowed to become completely dry.

Spray the release agent uniformly but sparingly to cover the entire surface (interior or exterior). Alternatively, the release agent can even be applied with a brush. For best results, hold the can at a constant distance from the surface (12” to 18” is recommended) and ensure that the same pressure is applied. Do not go overboard, as too much release agent may cover the details and lead to irregular distortions. This can also end up causing stains or air bubbles.

Allow the release agent to dry for 10 minutes or so before applying/pouring the mold making or casting material. In case an in-mold paint is to be used, it should be applied after the release agent dries. Once cured, the mold or cast can be easily removed by loosening around the edges.


Where to find?


EnvironMolds is the best resource when it comes to everything to do with how to make molds. It provides two great mold release options –

  • ArtLube100 is a silicone-based release agent specifically formulated for use with polyurethane molding systems and KastEZ urethane casting system. It can also be used with other polyurethanes, epoxies, polyester resins and silicone rubbers.
  • IsoKote 1000 (formerly Synlube 1000) is another silicone-based release agent formulated for the release of both low and high temperature cured urethanes from metal and plastic molds. It can also be used with epoxies.

Then there is MoldEZ Hair and Mold Release, a water soluble release agent that prevents alginate from tangling in the hair when making body molds.
 

 

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The Art of Life Casting Explained

Posted by EnvironMolds , Labels: , , , Thursday, January 6, 2022 11:15 PM

Getting into the nitty-gritties of life casting will show that it is complicated for sure, but doable with some practice and a lot of care. The artist has to always consider that he/she is working on a live model!

Life casting is a specialized art of making a three dimensional copy of the human form with a high level of realism and detail. Highly skilled molding and casting techniques are used to capture the finest of features of the human body; it can be any part from the face, hands and feet to the torso or the entire body.

Going way beyond a painting or photograph, the sculpture will recreate each and every fingerprint, dimple, fold and other lines on the body to imitate the physical presence and essence of the person. Life casts can be made with or without clothing.

How does it go?


The model is first prepped for what lies ahead. The pose is discussed and practiced while keeping comfort and safety in mind. Petroleum jelly or other release agent is applied first to prevent the body mold from snagging in the body hair.

Alginate, which is safe for the skin, is commonly used to make the body cast. It should be mixed with soft water in the specified ratio to form a creamy mixture of a workable consistency. The hand or foot has to be merely dipped into the alginate container and allowed to set. This works quickly and the body part can be slowly wriggled out to leave a negative mold behind.

A more complicated but proficient method is to apply the alginate on the body. It has to be carefully spread and smoothed into all the contours while taking care of the eyes, nose, ears, hair and so on. The artist has to work quickly as the alginate tends to set quickly. It is then reinforced with plaster bandages; this shell mold will enable the alginate to retain its shape.

The mold can be demolded pretty soon, all it takes is working the fingers under the edges and wriggling the body a bit. It can be corrected if needed and will be ready for casting. Plaster or other casting material is poured into the mold and allowed to cure. Just remove it and finish as desired. Some people even insert a wire or hook in the casting material itself and it can be hung on the wall later.

Keep in mind that the casting should be done quickly too, as the alginate will tend to shrink as it loses water on contact with air. Moreover, these are one-off molds and cannot be used for making multiple copies.

Making a body casting involves complex procedures, but the going gets easy and straightforward with time. The life casting artist has to be particularly careful about the model as it is a live person that he/she is working on here! Last but not the least; life casting is immensely satisfying and rewarding…..make the most of it!
 


 

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Process to Craft Flawless Life Cast

Posted by EnvironMolds , Labels: , , , , Tuesday, December 28, 2021 1:53 AM

 

Body casting is a popular type of art in which the human form is replicated in three-dimensional constructions. Full body castings are frequently created by experienced casting artists for theatrical or other aesthetic purposes, such as movie props. These castings are often made with skin-friendly and environmentally friendly mold making materials. Two typical materials used to create the master copy of the subject are alginate and plaster.

Generally, any life casting is completed in three pieces - head, rear and the torso. After separately making each of these parts, they are then seamed with each other through careful and precise techniques. The head is generally the last part to be attached to the cast.

Once removed from the mold, the body casts typically needs elaborate finishing touches.

To give it a semi-gloss, sometimes artists add polyurethane varnish for a pleasant look. Some life casting material kits comes with a specialized form of wax which when polished on the cast gives a marble-like shine. Depending on the need of the casts, the final color or the look can be done.
 

 
 

 

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Playing with Temperatures for Better Resin Casts

Posted by EnvironMolds , Labels: , , , , Thursday, December 16, 2021 3:57 AM

The temperature of the resin as well as the room should be on the warmer side to ensure that the resin castings cure properly and are free of bubbles. Following are some tips on how to get the temperature right.

Resins come as a two part system – the resin and hardener (or catalyst) have to be mixed together in the specified ratio to make it workable. Here, it is not only about how the two parts are mixed, but also the temperature at which they are used.

Indeed, the temperature of the resin mix as well as the room will determine the quality of the resin casting!


Manipulating the temperature


Resin cures best in warm and dry environments. In case the resin is too cold, it will become thick and may not mix properly. Moreover, the mixing procedure will tend to trap air which will show up as pesky air bubbles in the cast. The resin also fails to cure properly in a cool room and will turn out soft, bendy or with cloudy streaks.

On the other hand, when the resin, hardener and the surroundings are warm enough, they will support the chemical reaction that is essential for the curing to take place.

So, if the resin and hardener are not warm enough, they need to be heated prior to use. The trick here is to place the bottles in warm water for around 10 minutes before mixing. Do not use too hot or boiling water as it will accelerate the curing, thus shortening the pot time. The resin may start curing even before it has been cast!

Another point to note is that the bottles should be dried properly after removing from the water as any droplets of water that fall into the mix can again affect the curing.

In a similar vein, the temperature of the art studio should be maintained around 70℉ to 75℉. If the space is cooler, it is advisable to turn up the heat in the room and close the door prior to starting the casting process. This will even dry up the room a bit. However, ensure that the temperature stays stable as any drop in the mercury can again delay the curing time of the resin.

Some artists even go as far as warming up the mold with a heat tool to ensure a perfect casting! Another option is to use a ‘hot box’ to keep the air around the curing resin warmer than the temperature of the room. Then again, do not overdo the heat either as the resin will cure too quickly in hot surroundings.

EnvironMolds is a one-stop shop for everything to do with mold making, casting and life casting. It offers top quality materials, supplies and tools including all types of resins and polyurethanes for making exquisite casts. The range covers jewelry resins, clear casting resins and even a special formula that can increase the size of the casting by 160%.

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Standard Procedures for Making a Silicone Mold

Posted by EnvironMolds , Labels: , , , , Saturday, November 27, 2021 3:00 AM

With silicone being a popular and useful mold making material that delivers variety of benefits, artists should be aware of the basics when working with this rubber. Following are some tips on the same.

There are varied options of materials when it comes to making molds. While any malleable material like clay, wax, alginate or resin can be used to create a negative of the master model, rubbers have emerged as the material of choice, especially for professional mold makers. Then again, while there is a choice of polyurethane, latex and thermoset mold rubbers, silicone is preferred for many a reason.

To start with, mold making silicone is easy to use. The material has sufficient working time and cures fairly quickly to deliver durable, tear resistant and heat resistant molds. In fact, the molds will last for years and can be used to make any number of castings.The molds do not shrink much either. A variety of materials – like wax, plaster, gypsum, resins and even low-temperature melt metal alloys – can be cast in a silicone mold. Demolding is also easy as silicone does not stick to anything except itself.

Basic Preparation


Silicone rubber can be used to make molds of anything from figurines, statues, architectural pieces and picture frames to soaps, candles, toys, jewelry and more. The applications also include conventional prototype tooling and stereolithography.

The silicone has to be mixed with the catalyst in the specified ratio prior to use. Both the base and catalyst should first be stirred in their own containers before weighing the required amount of silicone base into a clean mixing container. A useful tip is to tilt the container and roll the material all the way around the sidewall, leaving about two inches from the top. This may sound unnecessary at first, but the coating will work to keep the catalyst from getting absorbed into the container, thus giving a better mix.

After this, the required amount of catalyst can be weighed into the container. Mix the two together by stirring with a stiff, flat-ended metal spatula until a uniform color is obtained. It is better to keep scraping the container walls and bottom to insure a thorough mix.

While artists usually vacuum degas the silicone rubber mix, it is generally not needed for most applications as a uniform flow into the mold box is enough to minimize entrapping of air. In case it is being deaired, the mixing container should be filled only to one-third of its depth to allow sufficient room for expansion during the deaeration.

Additionally, it is noted that low temperature and humidity increases both the work and pot life of silicone rubbers. Some artists even opt to refrigerate the base material before using it in hot environments.

Finally, the catalyst container should be closed tightly after use as exposure to air for an extended period can cause a film or crust to form on the catalyst and this hydrolyzed material will lead to improper curing.

MoldRite 25 Silicone is a popular material for general silicone mold making. The quality of impressions captured by these silicone molds is exceptionally outstanding.

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Effect of Temperature on Mold Making and Casting

Posted by EnvironMolds , Labels: , , , , Wednesday, November 10, 2021 2:15 AM

Temperature can play havoc with the curing of molds and casts by delaying/accelerating the process or not allowing the material to cure at all. Knowledge of the properties will ensure better results.

It is not just about the technique or dexterity of the artist; the quality of the mold or cast is affected by many other characteristics as well. Temperature plays a starring role here – ranging from the temperature and humidity of the surroundings to even the warmth/coldness of the material and model/mold.

This is why it is always recommended that all rubber and resin compounds should be stored at room temperature (72°F/23°C). For instance, if a material is stored at elevated temperatures, like in a hot garage or in direct sunlight, both the shelf life and pot time will get reduced drastically. In contrast, if latex rubber freezes, it becomes unusable and has to be thrown away. Other frozen materials can still be used after they are brought back to room temperature.
 
Let us take a look at how the temperature factors can affect the making of molds and casts:

Cold – A cold environment will usually prolong both the working time and cure time of most materials like epoxy resins, urethane rubbers and platinum cure silicones. The evaporation process of latex rubber also gets delayed in colder temperatures. In case the environment is too cold, some of these materials may even fail to cure at all. However, tin-cured silicones are not as dramatically affected by colder temperatures.

Heat – The opposite is also true as higher temperatures are known to accelerate the cure time and most materials tend to cure much more quickly when it is hot. In fact, many artists deliberately apply heat to hasten the curing process. However, tin-cured silicone rubbers are again an exception as they are not as affected by heat and cannot be ‘heat cured’.

Humidity – Rubbers are best used in a low humidity environment. Higher humidity tends to accelerate the curing in tin-cured silicone rubbers while it has the opposite effect of slowing the evaporation and curing process in latex rubbers. Making molds or casts of urethane rubbers, plastics or foams in humid environments can cause bubbles or foaming in the material. However, platinum-cured silicones and epoxy materials are not affected by humidity.

In addition to this, if the model that is being used to make the mold happens to be too cold, the curing of the mold will take unnecessarily longer to cure and vice versa. Therefore, the model/mold should be brought to room temperature prior to use. When making a mold of a frozen model, it will start condensing once the mold material is applied which will in turn delay the curing. This is why it is better to use accelerated silicones as they will not be affected by the moisture.

Finally, good quality liquid latex rubber, silicone or epoxy materials can be easily sourced from EnvironMolds at https://www.artmolds.com/ at the most reasonable prices.

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Making Body Molds with Plaster Bandages

Posted by EnvironMolds , Labels: , , , , Tuesday, October 26, 2021 1:53 AM

Who says plaster bandages can only be used to make a mother mold? The plaster infused gauze can also be applied directly on some parts of the body to make form molds that are later used for life casting.

Plaster bandages are normally used to make a shell mold to reinforce the flexible alginate or silicone body molds. The plaster in the bandages sets to form a rigid structure that encases the flexible mold and helps it retain its shape.

However, the plaster bandages can directly be applied on the skin to make form molds as well. This is used on areas like the stomach, back, thighs and arms which do not have much contours or undercuts. The bandages are most common for making pregnancy molds of the abdomen to capture the shape of an expecting mother for posterity.
 
 


Following is a look at what goes into making a body mold with plaster bandages:

  • The model has to be prepped for the session – the artist should inform him or her about the process, like what to expect and how much time it will take. Discuss the pose and ensure that the model can stay in the position for half an hour or so. Props or support may be required.
  • Prepare the area for the session by lining the floor with a waterproof covering as the dried plaster can prove difficult to remove. The artist should also wear a protective apron or old clothing that can be discarded later.
  • An appropriate mold release – like petroleum jelly or olive oil – should be applied on the body as this will make it easy to remove the mold without pulling on the body hair.
  • The bandages have to be rolled out and wet before applying. Here it is better to use warm water as the wet bandage can chill the skin and become uncomfortable for the model.
  • Lay the strips on the body one at a time starting from the top and moving towards the bottom. Make sure to overlap them to form a strong mold. It is better to keep changing the direction of the bandages when building the layers and make them thicker at the edges. This will serve as a good grip when it comes to demolding.
  • Work out the air bubbles when applying the bandages. However, do not press down too hard as this will form dents and can even deform the mold.
  • Once done, let the mold set and dry before demolding. Carefully run a finger under the edges to break the seal from the skin. The mold can then be lifted off easily from the body.
  • Place it on a soft surface with the hollow side down and let it cure properly. It can then be varnished for some extra protection.

Plaster gauze bandages and other materials and supplies needed for making a life cast can be easily sourced at EnvironMolds. The art supplier manufactures and stocks top quality products and tools and is more than willing to assist with tips and instructions as well.
 

 

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