Engineering business solvents and hazardous waste reduction

Using alternatives to coatings with high solvent content can save costs, increase quality and help you meet health and safety and environmental legislation.

Examples of alternative coatings

Alternative coating systems include:

• medium and high solids paints - with a range of 40-70 per cent solids and 30-60 per cent volatile organic compounds (VOCs), compared with 20-40 per cent solids for conventional wet paints
• water-based paints - similar solids content to conventional paints but with far less VOCs (typically 10-20 per cent)
• powder coatings - a 100 per cent solids mixture of paint pigment and resin binder
• thermal and plasma coatings - specialist coatings such as metal and polymeric coatings that have to be applied at high temperature

In metal finishing, water-based coatings are now often used as a primer and basecoat with a medium to high solids topcoat. Powder coatings are often applied - electrostatically - without a primer coat.

You could consider other measures such as:

• using pre-mixed coatings to avoid mixing on site
• thinning or mixing coatings in a centralised mixing room, or preferably in an enclosed machine - use trained staff for this task and use automated equipment where possible
• not allowing machine process operators to mix their own coatings at the machine, as this leads to significant emissions into the workplace
• using a brush or sponge rather than a spray gun to apply dyes and stains
• dedicating lines, pots and guns to a particular colour or material, and batch sequence to follow one colour with another of the same or similar colour - this reduces the need for cleaning on changeovers and reduces waste
• optimising spray gun settings and setting procedures for spray gun operators - discourage them from altering spray pressures and other settings without permission
• ensuring that the fan pattern of manual guns is only a little wider than the object being sprayed - movement should be at a constant speed, optimum distance and parallel to the object
• controlling the temperature in the spray area to keep it constant and optimum for spraying
• spraying flat component parts before assembly of a product to avoid over-consumption of the coating
• using paper masking around spray booths to reduce the need for booth cleaning
• controlling the use of cleaning solvents by providing operators with a set amount each day or each shift - use triggered spray containers rather than free access to cans