Mixing and storing paints, solvents, and other coating products is an important part of routine operations in a collision repair shop. If done properly, your shop will operate efficiently, safely, and profitably. If not done right, it can result in higher costs, lower productivity, and unwanted environmental emissions.

When you open and mix coating products, you are exposing flammable and potentially harmful materials to the environment and are increasing the risk of a fire. Mixing the wrong chemicals can result in wasted material, and in some cases, pressure build up, heat generations, explosions, fire, and harmful gases. For example, if you don't use the proper mixing ratios when preparing a primer or topcoat, your resulting paint job will be of poor quality, wasting both your time and the expensive materials used.

The following steps will help ensure your mixing operations are being operated safely:

Before opening containers, check for sources of ignition such as open flames, cigarettes, spark producing tools, welding torches. Check to make sure the ventilation system in the mixing rooms is functioning properly so that explosive vapours cannot build up.

Before transferring flammable liquids, make sure that grounding or bonding wires are attached.

Before mixing, read the manufacturers' MSDS, product labels, or technical product bulletins to become familiar with the mixing instructions, and to know what materials can be safely mixed together, and what personal protective equipment is recommended.

Wear all personal protective equipment recommended on the supplier MSDS.

Whenever possible mix colours in house. When required, stir colours for the required time before mixing. This will minimize poor colour matches and wasted material.

For mixing colours, consult manufacturers' formulations typically found in a computer database. Use a 'smart scale' or computerized digital balance to ensure proper weighing of materials. Most systems provided by paint suppliers can make corrections to improperly mixed colours by automatic re-calibration. Check with your paint supplier for more details.

Mix only the amount of coating product that you will need for the job to avoid waste. Computerized mixing scales permits smaller, accurate preparation of colour formulations.

Make sure the colour formulation is the best match for the shade of the specific colour. Some coating suppliers provide alternate or variant formulations for a specific colour.

Before painting the vehicle, spray a small test panel to ensure you have the proper colour match to avoid a possible re-do, and wasted time and materials.

Avoid the use of high solvent coatings such as lacquers. Use low VOC coatings such as waterborne or high solids.

Apply the minimum number of coats for good colour match and hiding. Ask your paint supplier about the use of tinted primers to reduce the amount of topcoat needed.

Keep all containers closed, replace lids immediately to prevent vapours from entering the environment.

Manage your paint inventory wisely to avoid the high costs of disposing of 'stale dated' products. Use paint on a 'first in, first out' basis.

Store hazardous wastes in properly labeled, impermeable containers with adequate spill containment.

Clean up leaks and small spills immediately

Best Practices for the Paint Mixing Room http://concessions.nps.gov/document/paintmix.pdf