Minimising paint waste and safe paint disposal A guideline for the minimisation of waste paint and effective disposal or reuse In the past left over paint was considered to be an inevitability of any painting job. The only downside was that more money was spent on the paint purchase than necessary. Today, and even more so into the future, liquid paint will be regarded as an unacceptable waste material and disposal with household rubbish or to the drain will not be an option. The quantities of waste paint generated by the Australian community are considerable. For example, one study by the Monash Centre for Environmental Management estimated that between 10 and 15% of paint bought by householders and trade painters remained unused on completion of the painting. The study estimated that in Melbourne alone, some 2.7M litres of paint remains in household storage, as much as 1.8M litres might end up in land fill sites each year with possibly a further 22,000 litres entering the stormwater drainage or sewerage systems. Of particular concern is the improper disposal of older paints, many of which contained heavy metal compounds, notably lead and chromates, biocidal agents and otherwise toxic or hazardous constituents. We all therefore need to look for better ways to minimise the quantities of paint that are wasted and explore alternative methods of disposing of the excess paint which we cannot use, in order to reduce the environmental impact on air, water and soil. Buy only enough paint for the job Buying more paint than you need only costs money and leaves a potential disposal problem. The chances are that if you don't use the paint you buy in the first few months after purchase, it won't be used. However if it is to be stored, ensure that the lid is tightly sealed and the paint is kept under cover, away from heat and cold and combustion sources. Retail outlets and manufacturers provide guidance on calculating how much paint you need while Australian Standard AS 2311 Painting of Buildings Clause 1.8, also provides advice. With today's system of tinting paint, where you can purchase further cans of the same colour quite easily from your local paint store, running out of paint is not such a problem as it used to be. Provided that the application of the new can is limited to a discrete area, such as a wall of different orientation to that previously painted, any minor colour difference between cans should not be apparent. Minimising Waste If applying 2 coats of water based paint in the same day you do not need to clean brushes and rollers between applications of the same paint. Rather, wrap them in plastic, such as an old supermarket bag. This will stop them drying out. Alternatively, paint brushes used with solvent borne paints can be stored underwater! They can then be briskly brushed out on paper to remove the water before recommencing to paint. Prior to using thinners for cleaning applicators, and between washings, brush or roll the applicator onto an absorbent surface such as paper which can then be disposed of as domestic garbage. This removes excess paint or solvent from the applicator. Collect all the dirty wash solvent and store in a properly labelled container. After a few days the pigment particles will settle to the bottom leaving the useable solvent on top. This solvent can then be carefully poured off for reuse and the solids wrapped in paper and when dried, disposed of as normal household garbage. For latex (water based) paints, allow the paint washings to settle for a few days before decanting the liquid. The water phase may then be conveniently disposed of in the garden and the solids disposed as garbage. Left over paint Save a small amount of paint for touch ups, preferably in a small sealed can, in the case of solvent borne products or an inert plastic container for latex types to avoid rusting. However if you have more paint left over, consider applying a further coat. This will provide extra durability, help mask surface imperfections and improve appearance. Alternatively get your paint store to tint it to another colour for a different purpose or apply it to something you might not otherwise have painted, such as the garage wall or a fence. It is far better to put the paint to good use than allow it to find its way to the tip or for the organic volatiles to find their way into the atmosphere where they contribute to photochemical smog. If these alternatives do not attract, give it away to a friend or neighbour. Another use for acrylic latex paints is the addition of small amounts to a concrete mix to supplement the water. This results in a denser less permeable concrete but may result in colour variation between batches. To get rid of small residual amounts of paint which cannot otherwise be used, pour it onto an absorbent solid such as kitty litter or shredded paper, allow it to dry and dispose of in the garbage. Aerosol cans should be emptied by spraying into an old cardboard box. Never attempt to puncture or incinerate them. There is likely to be a developing trend to establish household chemical collection centres and waste recycling programs throughout Australia. Where this option becomes possible, do not mix incompatible products, for example a water based paint and a solvent borne paint, as the mixture cannot be readily recycled. Likewise do not contaminate the paint with other materials, such as sump oil or weedicides. Be sure to also leave the can label in place to identify your paint for the recycling process. ^ top