There are a number of products available that can be used to create a cracked effect for aging and for adding interest to pieces. Below is a rundown of products currently available through A. S Handover.
Polyvine Crackle Glaze
This water-based glaze is applied in between two layers of emulsion and causes the top coat to crack revealing the base colour underneath.
Apply the base emulsion and allow to dry. Apply the crackle glaze in one direction and allow this to dry completely. This coat must be smooth and even. If not, remove the glaze with a damp cloth and re-apply. Apply the topcoat of matt emulsion, thinned with water to produce an easily flowing paint. The top coat of emulsion paint should be the consistency of single cream . Apply at right angles to the crackle glaze coat. Load brush with a generous amount of paint and apply in one pass only, allowing the paint to flow off the brush. Do not over brush as this will mix the glaze and paint and no cracks will appear. The thickness of the topcoat determines the size of the cracks – the thicker the coat the wider the cracks.
Below is a great video on the step by step process:
Craquelure is a two-part application that reproduces the delicate look of cracked varnish. Applied to a decorated surface it will create fine web-like surface cracks within hours. The cracks are then coloured, generally with artists’ oil colour (for example raw umber) which will give an antique look, but other oil-based products such as coloured furniture wax or gilt creams can also be used to great effect.
Applicraft offers a choice of three mediums, one for small fine cracking, one for medium and one for larger cracks. It is the base coat used that determines the size of the cracks so select one which is most appropriate to your project.
The thickness of the base and top coats will affect the size of the cracks so always experiment first. Applicraft advises applying a thick coat of Step 1 with a clean dry varnish brush. Do not overwork it and allow it to dry completely.
Step 2 can be applied now or at a later time. Use a clean varnish brush, making sure you cover the area and don’t miss out bits. Brush it out smoothly as it is thick and sticky.
If Step 2 is very thick, put the jar in a bowl of hot water whilst working with it to help keep it fluid. Step 2 only has a minute or 2 of ‘open time’ and so immediately after application, lightly brush out any areas which have pooled.
To highlight the cracks, wait at least 8 hours after the application of step 2, dab a small amount of white spirit onto a rag followed by the artists oil colour, or gilt cream, etc, and rub it over the surface and into the cracks. Wait for 20 minutes and gently wipe away excess until you achieve the tint you require. Let it dry for a while. Use a little white spirit to help remove any oil residue if necessary.
Once it has been left to dry for 24 hours you can apply a coat of oil-based varnish to seal the surface.
Lefranc & Bourgeois
Lefranc & Bourgeois Cracking Varnish is designed for use with Lefranc & Bourgeois Ageing Varnish. It is designed to produce a pattern of cracks resulting from a chemical reaction which mimic a genuine craqueleur (which is the result of age). It can be applied to various surfaces including cardboard and wood, as well as works of art painted with acrylic, alkyd or oil paints.
First, apply a uniform coat of ageing varnish. Then wait either 1.5-2.5 hours (for large cracks) or 2.5-4 hours (for fine cracks). Then apply a thin coat of Cracking Varnish in the opposite direction to that in which the coat of Ageing Varnish was applied. Wait for 3 to 4 hours for fine cracks and leave the object to dry. Apply Brown Patina or Patina black to emphasize cracks, avoiding touching the object. Apply a new coat of Ageing varnish over the cracks to protect your work.
Vallejo : Acrylic Crackle Medium
The Vallejo medium can be used in a few different ways.
1. As a medium which is used between two layers of contrasting colours of acrylic color
2. As a medium which is used on top of two contrasting colours of acrylic, this has a less dramatic effect then above.
3. On a finished piece over the transparent Crackle Base 161 to produce a crackled surface.
In each instance the crackle medium is applied with a brush, it is worth experimenting as the thickness of the coat will affect the size of the cracks.