Crackle: Step-by-Step Guide with Varnish, Medium, and Paste

Crackle is a technique that creates cracks on a surface, like those on old porcelain or paintings. It can be done in three ways, each with a different result: crackle medium makes the top layer of paint crack, crackle varnish creates a network of cracks in the varnish, and crackle paste creates deep 3D cracks. If you’re decorating an item with a napkin, apply the crackle varnish only after the decoupage is complete.

Which Crackle Product Should You Choose?

One-Step or Two-Step Crackling?

You’ll come across both terms in tutorials. With one-component crackle medium, you apply one product between two layers of paint. Two-component or two-step crackle varnish has two components that you apply one after the other. The cracks form in the second layer of varnish.

How to Crackle with Crackle Medium

1. Paint the item with matte acrylic paint and let it dry. This color will show through the cracks.
2. Apply a sufficient layer of crackle medium and let it dry.
3. Apply a thin layer of a second acrylic paint in one direction, preferably in a contrasting shade. It will crack as it dries.

The thinner the top layer of paint, the finer the cracks will be. Pentart Crackle Medium is one-component and water-based.

How to Create Cracks Like Those on Old Porcelain

For this, use a two-step varnish that creates fine lines. Here’s how to use Pentart 2-Phase Crackle Varnish 100 + 100 ml:

1. Apply the first phase to the finished, dry, decorated object and let it dry.
2. Apply the second phase and spread it thoroughly over the surface with your fingers. It will crack as it dries.
3. Bring out the cracks: rub Pentart antiquing paste or liquid patina into the dry surface, then wipe off the excess with a cloth.
4. The second phase is not water-resistant once dry, so varnish the object a day later with a varnish that can be thinned with thinner.

For the Fineline 2 × 20 ml set, apply the first component with a soft brush and let it dry completely. The second component is solvent-based and takes several hours to dry, or even overnight. You can speed up drying with a hair dryer or heat, but not from too close, to avoid scorching the material. Then bring out the cracks with patina, pigment paste, or metallic pigment. The pack includes an instruction leaflet.

Which varnish should you use as a finish?

For a matte surface, use Pentart Matte Clear Varnish, a synthetic varnish that the manufacturer recommends as a topcoat for Pentart crackle varnish. To keep the gloss, use Pentart Gloss Clear Varnish, which is solvent-based. For Fineline, the manufacturer recommends gloss varnish because matte varnish would dull the gloss of the second component. Gloss varnish has a strong odor, so apply it only in a well-ventilated room.

How do you use crackle paste?

Apply Pentart Metallic Crackle Paste to a dry base coat. The thickness of the layer affects the depth and shape of the cracks. The manufacturer recommends using a hair dryer to dry the paste. In the article What Happens When You Mix Crackle Paste with Acrylic Paint, we show how the paste behaves with paint.

What affects the size of the cracks?

• Layer thickness – with medium, a thinner top coat of paint creates finer cracks; with two-step varnish, the crack lines depend on the thickness of both phases, while with paste, the depth and shape of the cracks depend on the thickness of the paste.
• Drying time – with two-step varnish, it affects how the cracks look.

Can you crackle furniture?

The manufacturer describes the crackle medium for use on ceramics, vases, wooden boxes, and picture frames, and crackle varnishes for decorated objects. Pentart Antiquing Gel is intended for restoring old furniture: apply it, then wipe it with a sponge or cloth to give the wood an antique look. It also brings out cracked areas created by crackling.

Can you rub wax paste into the cracks?

Not metallic wax paste. According to the manufacturer, Pentart metallic wax paste is not suitable for filling cracks because it is difficult to remove from them. Use antiquing paste or liquid patina on the cracks.

Crackle gives decoupage and painted objects an antique look. You’ll find crackle varnishes, mediums, and pastes, along with glues, in the decoupage glues and varnishes category. For instructions on how to apply a napkin, see the article about napkin decoupage.