Tips for Painting in Cold Weather

Cool weather is now approaching for much us which means it's time to make some adjustments to our painting process.  Cool weather can be a real problem for auto painting as the cooler temps slow evaporation of solvents and cure of 2K products needed to drive ultimate performance.  Solvents trapped in the film and longer process times can quickly hurt a shop's productivity and job quality.

The easy answer for those equipped with heated air make up spray booths is to crank up the heat.  However, due to the increased investment and gas/electric bills heated booths and prep stations really aren't an option for many shop owners.  We believe getting back to basics helps address the potential pitfalls that can lead to bad jobs and sluggish productivity.  Hopefully these basics will help.

  • Make sure the item you are panting is at least 65 degrees.  No matter how warm you can get the air temperature if the part temp is cold the evaporation and cure of the paint film will be reduced.  Try placing an item in a heated area overnight or invest in some infrared heating lamps (never use while actual painting takes place) to get the part temp up.
  • Use the correct surface cleaner.  Many painters will take short cuts on the surface cleaner and purchase items or make their own cocktail of cleaning solvent blends to save a few bucks.  Many times this will bite you in the rear and this is especially true in cooler conditions where evaporation of residual surface cleaner can be extremely slow and not easily noticeable.
  • Use the correct reducer and activator for the job.  Most manufacturers offer multiple speeds of activator and reducer for varying conditions.  Make sure you are using a speed rated for the temps you are working.  The faster evaporating solvents and faster curing resins in these items are designed to be more forgiving for cooler conditions.
  • Allow adequate flash times!  Paying proper attention to flash times during cooler conditions is critical to prevent solvent entrapment.
  • Use accelerator for approved 2K finishes.  Urethane accelerators (different than your hardener or catalyst) help speed the reaction needed to cure 2K urethane finishes.  Careful use is an asset to productivity but overuse can lead to short pot life and finishes that dry so fast they can easily trap solvent.
  • Change your booth filters regularly.  Good air flow is even more important as the temperature goes down so it's worth time to change your filters more often through the cooler months.

One thing we would also like to caution against is the use of furnaces, heaters, hot lamps, or any other potential ignition source when there could be solvent vapors present.  Sadly it happens every winter where someone is hurt or loses their shop because they tried painting with a furnace on and it ignited air borne solvents and their shop.  It's not worth the risk so don't attempt it thinking "it will never happen to you".