If you are using an exterior oil-based paint in hot weather and the paint is setting up too fast, what can you add to slow the drying?

When working with oil-based paints in hot weather conditions, it is common for the paint to dry too quickly, making it difficult to apply evenly and achieve the desired finish. To address this issue, the correct additive to use is linseed oil.

Linseed oil is a commonly used drying oil that can be mixed with oil-based paints to slow down their drying time. This is particularly useful in hot weather as it increases the open time for working with the paint, allowing for better application and a smoother finish. It helps to maintain the paint's consistency while providing the necessary flexibility for easier manipulation during application.

Other substances like turpentine can act as a thinner, which can also impact drying time, but it is not as effective in preventing the paint from setting up too quickly as linseed oil. Kerosene is not a standard additive for paint and may alter the properties of the paint negatively. Water, on the other hand, cannot be added to oil-based paints as they do not mix; it would lead to separation and degradation of the paint's properties.

Therefore, the best choice for slowing the drying time of oil-based paint in hot weather is linseed oil.