I have been using water based oils in my weathering work latley and it gives a third dimension to the work , bringing it of the page so to speak. The drying time neat is around 3 days but when involved in your weathering work with airbrushed enamels it is reduced down to around a day. I asked about the weathering powders as i have been using Mig powders which ar somewhat coarser than carrs powders and give more depth, its early stages but i am getting some pleasing results look at the Mins created this way.