Properly Preparing the Surfaces to be Painted

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Normand Cormier is Classroom Training Manager for North and Latin America for Axalta Coating Systems [email protected]. Photo Normand Cormier

There is still confusion about when to use the products available for cleaning surfaces prior to the various operations carried out during the repair process.

The law on the concentration of volatile organic compounds (VOCs) in automotive refinishing products came into force almost 13 years ago, yet there is still confusion about the correct preparation of surfaces to be repainted.

There are three options for cleaning surfaces: soapy water, cleaners to remove stains and prepare surfaces for sanding, and surface cleaners.

Soapy water

Soapy water is the first step, no matter what repairs need to be made. This removes any organic contamination that other products can’t (tree sap, insects, mud, calcium, etc.). Anyone who has ever tried to remove a hand mark from a part that has been handled without gloves knows that only soapy water will effectively remove this contamination.

Pre-sanding cleaners

These cleaners are composed of solvents, but have no CV limit in the regulations. They could be classified as degreasers. However, the regulations require that they be applied using a spray bottle (pressurized bottle).

They can only be used before sanding, to remove tar stains for example. Text from regulation: Cleaning products in manual spray bottles used to prepare surfaces prior to sanding are not covered by the regulations.

This is where confusion still persists in many workshops. Many bodybuilders believe that if they are still on sale, they can still be used as a final wash before applying color, for example. Another belief is that if the cleaner is in a spray bottle, then one can use it as a surface cleaner for all operations, which is not true.

Surface cleaners

The regulations define surface cleaners as follows: A product used to prepare motor vehicle surfaces for the removal of foreign matter prior to the application of a coating.

A coating could be an undercoat or color. Surface cleaners have a VOC limit of 50g/liter. This means that for every 1 liter of product used, 50 g of solvent will evaporate. This also explains why surface cleaners are water-based in order to meet this limit.


The only exception to the regulation is for products in aerosol cans. The Regulation does not apply to automotive refinishing products that are imported, sold or offered for sale in a non-refillable aerosol container. A spray bottle is refillable, and therefore not exempt.


It’s up to your shop to make sure it complies with the regulations. It will be easy enough for an inspector to check your purchases and compare the quantity of solvent-based vs. water-based cleaners. If the majority is for solvent-based cleaners, you could be in trouble…



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