Langridge Cobalt Driers 100ml

$14.50

Cobalt Driers (dries oil colours)

Acts as a drier for oil colours and mediums.

Constituents: Cobalt Octoate, White Spirit

Product Application

Added to oil and alkyd colours to increase the rate of drying. Oils ‘dry’ or harden to a tough, insoluble film by absorbing oxygen. Cobalt Driers are known as ‘surface’ siccatives (driers), accelerating the drying of the oil surface. They are not ‘through-film’ siccatives and do not perform as succesfully with thick films of oil (i.e. impasto technique)

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Description

Cobalt Driers (dries oil colours)

Acts as a drier for oil colours and mediums.

Constituents: Cobalt Octoate, White Spirit

Product Application:

Added to oil and alkyd colours to increase the rate of drying. Oils ‘dry’ or harden to a tough, insoluble film by absorbing oxygen. Cobalt Driers are known as ‘surface’ siccatives (driers), accelerating the drying of the oil surface. They are not ‘through-film’ siccatives and do not perform as succesfully with thick films of oil (i.e. impasto technique)

Cobalt driers made from cobalt octoate or cobalt naphtenate are the only recommended siccatives for artists oil colours and mediums as their addition in the correct proportion has a minimal effect regarding darkening and embrittlement of the paint film.

Langridge Cobalt Driers are to be used sparingly as its over-use will destroy paint films.

– It is recommended that Cobalt Driers should be added to an oil medium or artists’ drying oil rather than mixed directly into the oil paint.

– Measuring quantities of driers directly into small amounts of colour is difficult and prone to miscalculation. Langridge recommends addition to mediums and oils to reduce the likelyhood of over use and to simplify the artists’ studio practise.

– Once mixed with an oil or medium, the artist can dispense with concerns about constant ongoing additions of driers.

– Add Cobalt Driers as an approximate 1% addition. (i.e. To 500ml of Linseed Oil add 5ml of Cobalt Drier.) Shake or stir well together.

– When initially mixed together, the driers will impart a blue/green cast to the oil or medium with which it is mixed. Exposed to indirect sunlight for a few days will remove this colour difference (Exposing the oil or medium to indirect sunlight will not sun bleach or thicken the material). If used in correct proportions, the colour of the cobalt drier will not interfere with oil paints’ brightness or colour saturation.

General guide to drying rates using Langridge Cobalt Diers:

Drying Oil/ Oil MediumNo addition1% addition
Linseed Oil2-3 days1 day
Poppy/Safflower Oil7 days4 days
Stand Oil + Gum Turpentine (1:1)14 days7 days
Lean Medium (1 part Linseed Oil + 3 parts Gum Turpentine)2 days1 day
General Medium (1 part Linseed Oil + 1 part Gum Turpentine)2 days1 day

 

 

 

 

 

 

The table provides drying times based on a 10 micron thickness film of oil/medium applied as a drawdown over a non-absorbant card. Times listed are for paint films reaching a non-tack surface and not for complete through-film drying. Due to the variable nature of the artists painting technique, drying times may vary for complete drying.

Additional product information

Problems with ambient temperature and humidity.

Because artists drying oils (oils that dry to a hard, non-reversable film) absorb oxygen to harden, so the ambient temperature and humidity have an effect on the speed and success of film hardening. Oils, oil paints and oil mediums should not be applied in temperatures below 10o F or above 40oF. Relative humidity level should not exceed 50%. Moisture in a high humidity environment will create a fine layer of water on top of the paint film preventing oxygen from being absorbed. This will dramatically slow the hardening of the oil, potentially weakining the paint film even when fully dry. Temperature and relative humidity can be controlled in the artists studio with heating/cooling devices and the use of dehumidifying devices.

Accelerating the drying rate of a completed painting.

Cobalt Driers should not be applied to a painting to accelerate the drying of an already laid paint film. If a painting is taking longer to dry than is expected, it is recommended to place the artwork in a dry, warm, dust-free area with a steady airflow across the surface. Once paint has been applied to a painting no attempt should be made to add driers or rapid drying mediums on top to accelerate drying. This can lead to cracking and potential flaking of the paint film.

Accelerating the drying rate of varnishes.

Cobalt Driers cannot speed the drying of artists’ varnishes as they contain no oil. Artists’ varnishes dry by evaporation of the solvent. If a varnish remains tacky for longer than is recommended by the manufacturer, this may be due to latent solvent trapped in the preceding paint film. As it attempts to evaporate through the surface it will solubilize the resin of the varnish. Place the artwork in a dry, warm, dust-free area with a steady airflow across the surface.

Working properties:

Thinning
For best results thin with Artists White Spirit. However, Langridge Low Toxic Solvent may be substituted.

Appearance
Langridge Cobalt Driers is a dark blue colour liquid with characteristic White Spirit odour.

Clean Up
Clean brushes with any artists’ solvent (eg Gum Turpentine, Low Toxic Solvent, etc.). For further washing apply a small quantity of Marseille or other pure olive oil soap and massage the bristles of the brush to release any remaining colour. Wash thoroughly in warm water. Leave to fully dry before using for oil colours.