Liquid acrylic — usually sold as fluid acrylic — is ordinary acrylic paint with the same pigment load as the thick stuff, made to a thinner consistency, roughly that of heavy cream. It is not watered-down paint, and that is the whole point of it: it pours, flows and sprays without losing color strength.
One thing to clear up first, because the term is ambiguous. This article is about fluid acrylic paint for art and craft. It is not about the liquid monomer used for acrylic nails, and not about casting resin. Different products entirely.
The four acrylic viscosities
Acrylic paint is sold in four broad consistencies. They differ in how much water and thickener the binder carries, not in how much pigment is in them.
Heavy body
The consistency of soft butter. It holds a brush mark or a palette knife ridge and keeps it after drying, which is what you want for impasto and texture. Because the paint film is thick it also covers in fewer coats. You can mix solids into it — sand, pumice, glass beads — and the dried acrylic holds them in place.
Soft body
Thinner than heavy body, closer to yogurt. It levels out as it dries so brush marks mostly disappear, which suits flat areas of even color. This is the consistency most paint by numbers kits use, for exactly that reason.
Fluid
The consistency of heavy cream. Same pigment strength as heavy body, but it flows. You can brush it, pour it, drip it or put it through an airbrush. It is also the practical way to use up the last of a heavy body pot — fluid paint stirred into it loosens what is left.
High flow, or acrylic ink
Nearly as thin as water. Sold for pens, airbrushes, staining and calligraphy. Worth knowing that pigment-based inks like these hold their color far longer than dye-based inks, which fade with light exposure. Give the bottle a gentle shake before use so the pigment is evenly dispersed.
All four dry to the same thing: a flexible, water-resistant film. The consistency changes how the paint behaves while wet, not what it becomes.
Making your own fluid acrylic
You can thin tube or pot paint yourself. The one rule that matters:
Water thins acrylic, but it also dilutes the binder that makes it stick. Up to about a quarter water by volume is safe. Past roughly half, adhesion and film strength start to fail, and the paint can lift or powder later. If you want it thinner than that, use an acrylic medium — a flow improver, a glazing medium or a pouring medium — rather than more water. A medium adds binder along with the fluidity, so the film stays sound.
- Find a container. A squeeze bottle with a fine nozzle, with a mouth wide enough to get a brush into. Craft and dollar stores sell them cheaply.
- Add the liquid first. A half-and-half mix of water and glazing medium is a good general-purpose base.
- Add the paint. How much depends on how thick you started. Too little and the color is weak; too much and it will not flow. Opaque colors give a stronger result than transparent ones.
- Mix thoroughly. This is the tedious part and the part people skip. Stir with a coffee stirrer, or drop a small metal ball in the bottle and shake gently. Shaking hard whips in air bubbles.
- Clean the nozzle afterwards. A toothpick or a large needle clears the tip. Acrylic that dries in a nozzle stays there.
- Seal it airtight. Acrylic dries as the water evaporates. A square of plastic wrap under the cap helps.
What fluid acrylic is good for
Watercolor effects that stay put
Thinned fluid acrylic behaves much like watercolor — washes, wet-on-wet, wet-on-dry, layering — with one significant difference. Once acrylic dries it is insoluble, so a later layer will not lift or muddy the one beneath it. The trade-off is that you also cannot lift color back off, which is a standard watercolor technique. Adding a flow improver pushes it further toward watercolor behavior, especially on absorbent paper.
Pouring
Pour the paint onto a level surface and tilt it until it spreads. No brush involved. Mixed with a pouring medium rather than water, the paint keeps its film strength and stays workable long enough to move around.
A rough starting ratio is one part paint to several parts pouring medium — check the specific medium, as they vary. Layer colors in a cup, pour, and tilt, or pour lines and drag through them with a palette knife.
Cells
The rounded cells in poured work come from a few drops of 100 percent silicone oil stirred into the paint. More oil gives larger cells, less gives smaller ones. Wash the finished, dried piece with soapy water before varnishing, or the residual oil will stop the varnish adhering.
Glazing
A glaze is a thin, transparent layer of color over a dry one. Because you are seeing one color through another rather than mixing them on the palette, the result is deeper and more luminous than a single opaque layer. Fluid acrylic is well suited to it: thin the color with a glazing medium, brush it evenly over a fully dry layer, and let it dry before the next.
Dripping
Hold the bottle above the surface and let the paint fall. It pools and spreads in a circle. Tilting the surface afterwards pulls the drips into lines. It is the easiest of these techniques to try and the hardest to control.
What you need to start pouring
- A rigid, level surface. Canvas board, wood panel or heavy card. It has to be level or the paint runs off one side.
- Gesso, if the surface is porous. Card and paper soak the paint in and the color goes dull. Sealed surfaces like glass need no priming. There is more on this in our guide to what gesso is and when you need it.
- Fluid acrylic paints in a few colors. Colors that are opposites on the color wheel will turn muddy where they meet, so pick a palette that works together — our color wheel guide covers which combinations survive being mixed.
- A pouring medium. Not more water.
- Silicone oil, only if you want cells.
- Plastic cups and squeeze bottles, one per color, and something to cover the table with. This is a messy process.
Does any of this apply to paint by numbers?
Indirectly, and it is worth knowing. Paint by numbers pots are a soft body acrylic, chosen because it levels out and covers the printed numbers in a coat or two. You would not want fluid acrylic in a kit — it would run across the printed lines.
Where it matters is thinning. When a pot has thickened, the same rule applies: a drop or two of water is fine, but keep going and the paint turns transparent and stops covering the numbers underneath. Our guide to reviving dried paint in a kit goes through it properly, and if a pot has gone solid there is a matched replacement set for every design.
To sum up
Fluid acrylic is full-strength paint at a pouring consistency. Choose the viscosity for what you want the paint to do: heavy body to hold a mark, soft body for flat even color, fluid to pour and flow, high flow for ink-like work. Thin with a medium rather than water once you pass about a quarter water by volume, and the paint will behave.
You can see the Ledgebay kits in the shop, or look through the customer gallery.
