Liquid latex is a compound often used for

special effect Special effects (often abbreviated as SFX, F/X or simply FX) are illusions or visual tricks used in the theatre, film, television, video game, amusement park and simulator industries to simulate the imagined events in a story or virtual wor ...

makeup The asterisk ( ), from Late Latin , from Ancient Greek , ''asteriskos'', "little star", is a typographical symbol. It is so called because it resembles a conventional image of a heraldic star. Computer scientists and mathematicians often voc ...

body painting Body painting is a form of body art where artwork is painted directly onto the human skin. Unlike tattoos and other forms of body art, body painting is temporary, lasting several hours or sometimes up to a few weeks (in the case of mehndi or "h ...

, mask making, and casting applications.

Composition

Liquid latex is usually made of 33%

latex Latex is an emulsion (stable dispersion) of polymer microparticles in water. Latexes are found in nature, but synthetic latexes are common as well. In nature, latex is found as a milky fluid found in 10% of all flowering plants (angiosperms ...

, 66%

water Water (chemical formula ) is an inorganic, transparent, tasteless, odorless, and nearly colorless chemical substance, which is the main constituent of Earth's hydrosphere and the fluids of all known living organisms (in which it acts as a ...

, and less than 1%

ammonia Ammonia is an inorganic compound of nitrogen and hydrogen with the formula . A stable binary hydride, and the simplest pnictogen hydride, ammonia is a colourless gas with a distinct pungent smell. Biologically, it is a common nitrogenous was ...

(to increase its shelf life and to control the pH of the solution). Liquid latex is sold in volumes ranging from 2

ounce The ounce () is any of several different units of mass, weight or volume and is derived almost unchanged from the , an Ancient Roman units of measurement, Ancient Roman unit of measurement. The #International avoirdupois ounce, avoirdupois ounce ...

s to 1

gallon The gallon is a unit of volume in imperial units and United States customary units. Three different versions are in current use: *the imperial gallon (imp gal), defined as , which is or was used in the United Kingdom, Ireland, Canada, Austral ...

, and its consistency is similar to latex house paint. Its consistency can be augmented with the use of additives. For example, water can be added to thin the latex, and

Aerosil Fumed silica (CAS number 112945-52-5), also known as pyrogenic silica because it is produced in a flame, consists of microscopic droplets of amorphous silica fused into branched, chainlike, three-dimensional secondary particles which then agglom ...

can be added to thicken it. Cosmetic liquid latex contains approximately 0.3% ammonia, while craft and mould-making liquid latex can contain more than double this amount, giving the latter a much stronger odour. Liquid latex is naturally clear, and dries into a translucent amber colour. Manufacturers add pigments to the product to provide opaque paint choices of multiple colours. The colour of the paint in the jar may initially look chalky or pale, but as it dries, it develops into a rich colour (for example, grey becomes black).

Acrylic paint Acrylic paint is a fast-drying paint made of pigment suspended in acrylic polymer emulsion and plasticizers, silicone oils, defoamers, stabilizers, or metal soaps. Most acrylic paints are water-based, but become water-resistant when dry. Depe ...

can be mixed with liquid latex for custom colours, but may not be suitable for use in cosmetic applications. In these situations, liquid makeup or

food coloring Food coloring, or color additive, is any dye, pigment, or substance that imparts color when it is added to food or drink. They come in many forms consisting of liquids, powders, gels, and pastes. Food coloring is used in both commercial food ...

can be used. As the latex dries, it becomes quite sticky and will stick to itself if accidentally folded over. Most manufacturers offer a slick spray for latex once it is dry to remove tackiness, allowing the movement of the model's limbs. Alternatively, powders can be dusted over dried liquid latex to create metallic effects. One advantage to the tackiness of liquid latex is that it can act as an

adhesive Adhesive, also known as glue, cement, mucilage, or paste, is any non-metallic substance applied to one or both surfaces of two separate items that binds them together and resists their separation. The use of adhesives offers certain advant ...

for attaching items such as

zipper A zipper, zip, fly, or zip fastener, formerly known as a clasp locker, is a commonly used device for binding together two edges of textile, fabric or other flexible material. Used in clothing (e.g. jackets and jeans), luggage and other Bag, ba ...

s. Unlike most other body and

face paint Body painting is a form of body art where artwork is painted directly onto the human skin. Unlike tattoos and other forms of body art, body painting is temporary, lasting several hours or sometimes up to a few weeks (in the case of mehndi or "h ...

s, liquid latex is removed by peeling it off, since water does not reactivate it.

Use

Cosmetic/Special Effects Makeup

A four-

jar of liquid latex can typically cover an average human body. It is typically applied using a disposable sponge and takes about five to ten minutes to dry depending on how thick it is applied. As it dries, it solidifies to a rubbery consistency and in the process ends up shrinking by approximately 3%. Removing latex from skin can cause pain or pull body hairs out, similar to

waxing Waxing is the process of hair removal from the root by using a covering of a sticky substance, such as wax, to adhere to body hair, and then removing this covering and pulling out the hair from the follicle. New hair will not grow back in the pr ...

. Even though latex is non-toxic, some people can have an

allergic reaction Allergies, also known as allergic diseases, refer a number of conditions caused by the hypersensitivity of the immune system to typically harmless substances in the environment. These diseases include hay fever, food allergies, atopic derma ...

to it. The most severe of these happen immediately and are categorized as an immediate

hypersensitivity Hypersensitivity (also called hypersensitivity reaction or intolerance) refers to undesirable reactions produced by the normal immune system, including allergies and autoimmunity. They are usually referred to as an over-reaction of the immune s ...

reaction. Fumes from the ammonia in liquid latex can irritate the eyes when it is used on the face. For this reason, it is recommended that liquid latex be allowed to vent for several minutes before being applied in this way. Appropriate liquid latex safety guidelines should be followed before the cosmetic use of liquid latex. Liquid latex used for special effects makeup projects like scars and gashes incorporate flesh-coloured latex that is applied to the skin and then built up using materials such as

tissue paper Tissue paper or simply tissue is a lightweight paper or, light crêpe paper. Tissue can be made from recycled pulp (paper), paper pulp on a paper machine. Tissue paper is very versatile, and different kinds of tissue are made to best serve these ...

and

cotton Cotton is a soft, fluffy staple fiber that grows in a boll, or protective case, around the seeds of the cotton plants of the genus ''Gossypium'' in the mallow family Malvaceae. The fiber is almost pure cellulose, and can contain minor perce ...

Mold Making

Liquid Latex is useful for molding due to its flexibility once dried, which allows for the casting of undercut sculpture. There are several methods for making a latex mold, each with numerous variations. Below is a general outline of several methods. In any method of mold making, care must be taken to avoid air bubbles on the first layer of applied latex.

Brush Method

First, the original object to be molded (master) is cleaned and dried before being paced onto a non-porous substrate. Next, liquid latex is painted onto the master, leaving the bottom uncovered, but painting out around the base on the substrate. Latex must be painted on in multiple layers, allowing the latex to dry between each one. The drying process can be expedited with the use of a fan or hair dryer. The number of layers applied typically ranges from 8 to 20, though more may be necessary depending on the size of the mold. A latex mold of a chess piece 15cm in height would normally take 8 - 10 coats. Reinforcement, such as burlap, string, or cheesecloth, may be added between layers to strengthen the latex, and prevent tearing during removal from the casting.

Dip Method

If your master is porous enough to draw moisture from the latex, you can simply dip the master into the liquid latex to make your mold. After dipping, bubbles may form on the surface of the master. If this happens, pop the bubbles with a brush and re-dip immediately. Allow latex to dry in between dips.

Removing the mold

Once the latex is completely dried, the latex mold is then peeled off, turning the latex mold inside-out in the process. Talcum powder or soapy water should be applied to the outside of the mold before removal, to prevent the latex from sticking to itself. After popping the latex back into its original shape, you can then use the mold to cast the item in your casting medium of choice.

Safety

Due to the presence of

Ammonium Hydroxide Ammonia solution, also known as ammonia water, ammonium hydroxide, ammoniacal liquor, ammonia liquor, aqua ammonia, aqueous ammonia, or (inaccurately) ammonia, is a solution of ammonia in water. It can be denoted by the symbols NH3(aq). Although ...

, liquid latex may cause skin irritation and eye irritation. The amount of

Ammonium The ammonium cation is a positively-charged polyatomic ion with the chemical formula or . It is formed by the protonation of ammonia (). Ammonium is also a general name for positively charged or protonated substituted amines and quaternary a ...

varies greatly, and depends on the latex's intended use. Liquid Latex intended for mold-making may cause serious eye irritation. If liquid latex gets in your eyes, rinse cautiously with water for several minutes. Remove contact lenses, if present and easy to do, and continue rinsing. Latex is also a common

allergen An allergen is a type of antigen that produces an abnormally vigorous immune response in which the immune system fights off a perceived threat that would otherwise be harmless to the body. Such reactions are called allergies. In technical terms ...

, and may trigger an allergic reaction in some people. Should liquid latex start on fire, water fog,

foam Foams are materials formed by trapping pockets of gas in a liquid or solid. A bath sponge and the head on a glass of beer are examples of foams. In most foams, the volume of gas is large, with thin films of liquid or solid separating the reg ...

, dry chemical powder, and carbon dioxide are suitable extinguishing media. A water jet should not be used, as this will spread the fire.

References

{{Reflist Body art Rubber Special effects