Painting in Cold Weather
- Additive to make latex paint flow like oil paint in cold weather. 
Floetrol Instruction for Cup Spray Gun
WHEN PAINTING WITH A CUP GUN SPRAYER - from PDF 
- Floetrol acts as a stir-in lubricant.
- Helps cup guns work with acrylic/latex paints.
- Mix at least 4, but not more than 8, ounces of Floetrol into each quart of paint.
So: 5 gallon bucket gets 1.25 gallons of Floetrol, for extreme weather.