During my journey in acrylic pouring I’ve seen several tutorials and read uncountable number of articles about different materials in terms of mediums and additives. And whilst experimenting it often happened to me that I didn’t know if I had the right product or if I had to spend more money on art supply to get the right ingredient. For this reason I decided to put black on white a little list of the most used mediums and additives in pouring art and below is what I come up.
Acrylic Mediums vs Additives: what is the difference?
The main difference between acrylic mediums and additives is that acrylic mediums contain high proportions of acrylic resins, but additives do not.
This makes it possible for most acrylic mediums to be used on its own or to be added freely to colours without weakening the stability of the acrylic film. In essence acrylic mediums could be considered as colourless paints, made from a water-based acrylic polymer binder. Examples of mediums are pastes, gels, acrylic varnishes and fluid mediums.
Additives, on the contrary, don’t contain a binder and for this reason can’t be used on its own. They had to be added to another medium or to paints following the instructions on the labels. Examples of additives are water, acrylic retarder, acrylic thickener.
Below I have listed the most important mediums and additives.
List of acrylic mediums
Acrylic Binder
The acrylic binder is a water-soluble acrylic polymer emulsion, that keeps together the pigments, creating a glossy, transparent, water-resistant, age-resistant film when dried. It is the acrylic medium par excellence. and one of the main components of acrylic paints.
Acrylic (Painting) Gel
An acrylic gel (or painting gel) is a water-soluble medium that is used to change the consistency of the colour or, in the case of phosphorescent acrylic paints with a glow-in-the-dark effect, to give them a certain property.
It presents itself as a paste that is used to thicken paints, give them a texture (impasto gels), to change their appearance (glossy, matt or iridescent gels), or keep a shape. For this reason it is used in combination with PVA-Glue to create the right paint consistency for blob paint.
(Acrylic) Pouring Medium
The (acrylic) pouring medium is a liquid that can change the bond created by the acrylic binder and, similar to water, it is use to dilute acrylic paints. It is usually white but dries transparent giving back the colours their original brightness.
GAC Product Series by Golden Acrylics
GAC are fluid mediums that are used to change the viscosity of paints. They look white but become transparent and translucent when dried. They are available in the following variations:
GAC100 Primer/Extender, which is basically used as a thinner or a sealer
GAC200 Hard Acrylic Extender for Non-Porous Surfaces
GAC400 Acrylic Medium for Fabric
GAC500 Gloss Extender for Fluid Acrylic
GAC800 Low Crazing Extender for Pouring, is a pouring medium and prevents the painting from cracking
GAC900 Heat-Set Fabric Painting Medium, to easy the paint on fabrics and makes them permanent once heated with an iron.
The most used in pouring are GAC500 and GAC800 (See more).
List of additives
Acrylic Retarder
It is a jelly like additive used to retards the drying time of acrylic paints.
Acrylic Thickener
It is a jelly like additive (mixable with water to dilute it) used to change the paint consistency by making it thicker.
FLOETROL ©
FLOETROL is a very expensive additive used to transform and improve the properties of water-soluble paints so that they can be processed like synthetic resin paints in terms of extension of their drying time, improvements in the processing properties and elimination of brush marks.
Even though it is used to mix acrylic paints it is not a pouring medium. It only improves the colour’s fluidity and the appearance of the pouring designs created.
In commerce there are more versions (i.e. US, Australian) with small differences in the recipes.
Besides the above mentioned mediums and additives there is another category of products that are used as mediums or additives even though their primary application is not connected to the pouring art.
List of products with another primary application
Mod Podge ©
Mod Podge is a kind of glue (not PVA-Glue!) which is used both as glue and as final varnish to seal a creative project (i.e. collage, decoupage, etc.). It present itself as a white liquid but becomes transparent once dried.
Due to its bond strength it can be also used, diluted with water, as a pouring medium.
In commerce there are different variations: glossy, satin, matt, antique matt, high glossy, etc.
Many artists use this product instead of PVA-Glue to create their own blob paints.
PVA-Glue/Vinyl Glue
PVA-Glue (Polyvinylacetat), also called Vinyl Glue (i.e. Vinavil ©) , is a dispersion of polyvinyl acetate resins in a water-based solution containing PVA adhesives. It has the appearance of a milky white liquid, which becomes colourless when dries, and is mostly odourless and no-toxic.
Due to its properties (it has a high bond strength) it can be used
with pigments, as an acrylic binder, to create custom colours
mixed together with (distilled) water as a pouring medium. In this case the ratio should be 70% glue + 30% distilled water.
mixed together with a glossy gel medium and a ready-to-use acrylic paint to give them the right consistency for blob painting.
Lacquer/Varnish
Lacquer or varnish is a liquid material that forms a transparent, resistant and elastic film when it dries. Lacquer can range from dull matt to high gloss.
The lacquer is made up of 3 components:
a binder, which is responsible for forming the protective film. The binder is usually a synthetic resin. The best known resins are acrylic, vinyl, polyester, epoxy, polyurethane and alkyd.
A solvent, which can be water or another liquid. It gives the paint its flowability and evaporates when the paint dries.
A plasticising agent that is responsible for flexibility after drying.
The varnish can be found on the market either in transparent form (mainly as a top coat) or in coloured form under the name of paint or enamel due to the pigments it contains.
Polyurethane-based varnishes
This is a different type of topcoat that is more resistant than normal varnish and can be produced on an oil, water or oil/water basis. The oil-based varnish has a more yellowish surface, while the water-based varnish remains transparent after drying.
Although it is the best topcoat, it can be difficult to work with due to the chemicals it contains, which have a strong odour and produce toxic fumes, as it is solvent-based. These products are also highly flammable, making them unsuitable for use in acrylic moulding techniques where the paintings are torched.
Polyacrylic-based varnishes
This type of topcoat is an alternative to polyurethane varnishes. It is ONLY water-based and, unlike polyurethane varnishes, has the advantage that it is not as toxic as the oil-based version. It dries faster, but the sealing effect lasts a little shorter.
An example of this type of product used in acrylic pouring for mixing pigments is Polycrylic (Minwax). Polycrylic is a water-based top coat, similar to varnish, white in colour when still wet and is mainly sold in the USA. In Germany it is sold at amazon and costs about € 32.00. Its glossy version is usually mixed with MICA powders to improve their gloss effects.
Shine Grade Designations and Interpretation for varnish
Matt paint: Matt paint has no gloss at all. there are different levels of matt finish for paint. For example, extra matt, dull matt and silk matt.
Silk gloss: Silk gloss is a medium level of glossy. Once dried it gives the surface a warm appearance.
High gloss: High gloss is the glossiest of the three.
Glossy-Values (Values are %)
dull matt 0-6 Glossy
matt 8-10 Glossy
matt - semi-matt 12-15 Glossy
semi-matt 20-30 Glossy
silk gloss 30-55 Glossy
glossy 60-80 Glossy
glossy - high gloss 80- 100 Glossy
I hope you find this list helpful.
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Happy pouring and have fun by experimenting!
Laura
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