Over the years much has been written, talked about and passed on from father to son about the best temperature for applying paint.

Most of this is based on the use of cellulose paints which, due to their very high VOC levels (Volatile Organic Compounds – the stuff that is not doing the ozone layer any good) are now restricted to certain industrial uses and classic vehicle restoration.

Cellulose paints requires a warm dry atmosphere otherwise the paint 'blooms' and leaves a opaque finish when dry.

Most other types of paint require totally different conditions for successful application, this will be dependant on what they were originally designed for.

Oil based enamel paints were originally designed for painting vehicles in cold, damp barns or warehouses and are in part based on the needs of the RAF during WWII.
Whilst heating up a specifically designed paint shop to mass paint a production line of cars is a viable prospect, heating up a barn with holes in the walls and badly fitting doors is certainly not.
As such 'Coach Enamel' paints have to be able to dry properly in zero degrees and with a very high moisture content in the air.

The up side of this is that warm dry conditions are not required to ensure a good finish, the down side is that the higher the temperature the faster the paint dries leading to major problems with application.

Brush application of Oil based paints is best done at low temperatures, we recommend 10 degrees Celsius or below. However, this can also lead to problems as the paint, particularly gloss, tends to be very 'thick' due to the low temperatures. In these conditions it is possible to thin the paint slightly to allow ease of application. In this case put a small amount in to a separate container and thin this. DO NOT return this to the stock tin. Solvent based thinners cause a reaction in the paint and this can cause the paint to gel and become total unusable.

Having said all that temperatures of 10 degrees celcius or below are not the most comfortable, particularly if you have large areas to paint.

It will therefore be a case of trial and error to find the temperature and paint to thinners ratio that suits you.

Remember that the thicker the coat the longer it will take for it to dry all the way through and this will be exasperated in warmer temperatures because the top surface flashes off and restricts the egress of solvents from below.

The warmer the temperature, and thus the quicker the top surface flashes off, the more likely that gloss paints will appear as satin, this can be further exasperated when spraying if you spray from too far away, thus allowing the paint to dry on route.

For more information see other pages in the useful information section of this website or our book 'The Finishing Touch'