We're in favor of full transparency over here at Heron. We use a manganese drier in our linseed oil paint that adds a very small amount of VOCs. The manganese drier equals >= 0.075% - <=0.12% of our paint formula. In order to be considered a Zero-VOC product, paints need to have less than 5 g/L of VOCs. Our maximum VOC content in our paint is calculated at 1.89 g/L. The rest of our paint comes in with less than that. Because of the nature of our paint, its high solids and its processing, the small amounts of VOC will probably remain in the paint due to cross-linking reactions with the linseed oil. This needs to be studied more, but has been documented in emmision tests conducted by others.
We add this drier to decrease the open time of our paint. Different pigments and varying North American climate regions affect the polymerization of the oil. The drier is added to make these regions and pigment variations less impactful on the curing of the film. We know you can't always paint in the most perfect of conditions.
We go through the effort to create our purified linseed oil in order to cut down on the amount of drier needed. Simply put, a really clean oil polymerizes much faster than raw oil. A raw, cold pressed, and filtered oil would require larger amounts of driers to behave like our purified oil.
Our goal is to make the cleanest, longest lasting alternative to modern plastic coatings, and we believe we've done that. Keeping VOCs at a minimum in and around your home as well as our place of work is incredibly important to us. We feel comfortable manufacturing this paint, and we think you can feel at ease using it on your projects.
If you'd like to order any of our colors without the manganese drier, feel free to email us with a request.
For those who are chemically sensitive, it should be known that natural drying oils oxidize during the curing process and produce aldehydes and hydrocarbons. Peroxides, ketones, acids and alcohols may also off-gas during oxidation. The off-gassed compounds can cause symptoms to the chemically sensitive.