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So, the color of my dyed plaster died. After I finish up the details and smoothing of this piece, I'd like to restore the color with some paint.

What type of paint will work well for this?

I need something that will:

  • Hold fast
  • Work easily on the semi-porous plaster
  • Not seal in moisture in the piece, or add to it
  • Preferably semi-glossy to glossy
  • Not smooth out my fine edges and detailing, or thicken/round them
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  • No experience with it, so reluctant to answer, but people have been painting plaster with acrylics for many years. I'd start my research there.
    – Joanne C
    Commented Jul 4, 2016 at 2:26

3 Answers 3

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Since you don't want to loose any surface detail in your casting and it's a porous material you are wanting to colour, have you considered using a dye or stain instead of a paint?

Using dyes, you chemically change the colour of your material. Adding no thickness to the item being coloured.

I don't have much experience with dyes other than colouring Easter eggs. Using melted wax to mask areas allows for ornate designs to be created.

Here's a demonstration of the process.

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  • Is it possible to do after it's set? Something like that would work, if I could apply it with a paintbrush.
    – user24
    Commented Jul 3, 2016 at 4:01
  • I don't know. Could you cast, and allow to set, a small test piece? That way you could experiment try various dyes without worrying about wrecking your main pieces.
    – John Vukelic
    Commented Jul 3, 2016 at 4:47
  • there is another question here on stack exchange that is very similar to what I proposed about the use of dyes to chemically colour the plaster. But note in the discussion section about the importance of using dyes specifically made for the material you are working with crafts.stackexchange.com/questions/1873/…
    – John Vukelic
    Commented Jul 3, 2016 at 12:45
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The easiest solution is to paint with an emulsion, such as those used on interior household walls.

Bare plaster needs to be suitably sealed before painting begins otherwise the paint will sit on the surface and come off very easily.

You can do this either by applying a couple of emulsion mist coats:

  1. Dilute an initial solution of 60:40 water to emulsion
  2. Then a second mist coat with the ratios reversed, to thicken the coverage but still watery enough to allow it to continue to sink into the plaster below

Or, you can buy a purpose made primer. The link is for a UK site, but is very likely to be a product available worldwide. If the plaster is overly polished, this latter option will be the best, as the plaster will not allow the mist coat to seep in and adhere properly.

Within the hour, the piece will be ready for the second mist coat. Apply this in the same order as the first.

You can now apply the final coats (either silk or matt are suitable finishes - but silk is a more reflective surface that draws the eye but can accentuate any imperfections). Depending on how intricate the piece is will depend on how many coats you might want to apply. The more coats, the more the details will be smoothed out by the paint thickness.

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Most paints don't stick very well to cured plaster so it is often best to seal the surface first.

If you have a lot of surface detail then shellac can work well as this will seal the surface without obscuring detail. This should take oil and acrylic paints.

You can also use polyurethane varnish, this will cure OK on slightly damp materials and will take most paints and finishes but is more prone to streaks, drips and filling in surface texture.

You could also consider using tinted waxes, these can be quite good for simulating stone, terracotta and cast metals and tends to look a bit more natural than paint.

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