Whether you are creating fine art or a first-time concrete user making DIY planters for your houseplants, metallic gold can be a dramatic way to add visual interest to your project. Layers of metallic gold within a cement art object can create an effect that reminds me of geology, shaping the illusion that the pigment and layers of cement and “gold” settled naturally.
Quick Set Cement (I recommend and use Rockite)
Golden High Flow Acrylic Iridescent Gold Paint (Don’t try another brand or anything other than the “High Flow” blend- only the high flow blend can permeate the pigments in such a thin thread.
I tested this with other gold paints and was not pleased with the effect. Even Golden’s “liquid” acrylic in the same color produced an effect that looked like a layer of gold plastic that would peel away from the concrete layers if touched.
How To Create Gold Veins in Cement
The effect is achieved by pouring cement into your mold a bit at a time, and patiently adding, between cures, a layer of high flow acrylic paint. The high flow paint works because it spreads to form a super-thin layer between the pours.
Fill your mold with the first layer or two of cement. To create visual interest within the cement layers, try 1. using white pigment to create color variation and 2. pouring the concrete very wet and placing the mold on an uneven surface so the cement dries not-quite-level. Allow cement to quick cure (about 15 minute) between cement layers.
Wait 15 minutes for the cement layer to become firm to the touch and mostly cured, then add a few drops of gold high flow paint to the surface of the cement. Be very careful to avoid dripping paint onto the sides of the mold, if you do get paint on the mold, carefully wipe the paint away. (a tiny amount of residue remaining on the mold is ok- it will transfer to your piece but can easily be sanded off during finishing)
Only use a few drops of paint. You don’t want to create a thick layer, just what will appear to be a thin thread of gold. I create this ultra-thin layer by dropping 5-10 drops of the ultra-thin paint onto the surface of the cement, then manually tilting or spinning the mold so the gold paint settles on the outer edges where it will be visible when my piece is unmolded.
For a sedimentary gold vein effect, wait until the gold paint is completely dry to the touch before pouring additional layers of cement on top of the gold. This may take up to two hours but typically if I am working with curing (hot) concrete in well-ventilateded area, 20-30 minutes is sufficient time to allow the paint to dry enough that it won’t float up when the next layer of cement is poured.
TIP: avoid regularity. As you can see in these pieces, the gold veins sometimes peter out or end abruptly. This was intentionally created to mimic natural gold veins in rocks. To create this organic look, when you apply paint to your cement just avoid swirling and spreading your paint to the point of uniformity, instead letting it pool in some spots and tilting your piece to prevent pooling in other areas.
VARIATION: A different effect can be achieved by pouring fresh cement atop still-well gold paint. A very liquid wet cement applied over fresh gold paint can create an effect ranging from obliteration of the gold into the viscosity of the cement, to a wispy marble-like effect swirling the paint into the cement.
Unmolding your Gold Vein Cement Piece
Don’t panic if, upon unmolding your concrete creation, the gold lines seem messy or lost within the concrete. Instead, run a fine grit sandpaper over the surface of your object to remove pigment and debri transferred by the mold. This slight sanding will expose the true colors of your piece including the delicate veins of gold.
When to unmold?
Almost all instructions say to wait 24 hours before unmolding cement, but when I’m working with Rockite and I’m using a solid mold that has thick, sturdy walls, I unmold within one to three hours. The cement at this point is not fully set, and the work of sanding and finish is ultra-easy on the somewhat soft and porous half-cured cement.
Adding Gold Veins to Already Poured Cement
When unmolded early, the layers you’ve created are more likely to separate, having not fully cured together. Handle carefully to avoid this, but if you do find sections separating, you have two options: First, a thin glue (such as superglue) can rejoin them without damage or evidence of the split, or second, you can use liquid acrylic paint in place of the glue. Applying generously between layers and squeezing the cement back together can create an entirely different, but equally cool, effect of the gold paint filling and artfully oozing out from between layers.