Recipe for aero testing fluid?

Hi

In the May 2010 'Wing It' aero section, mention was made about a recipe for aerodynamic testing fluid. It simply mentions water-based paint powder, Three-in-One oil, and rubbing alcohol, but not ratios. Does anyone have a good starting point?

Thanks

I'd try a 1:1 ratio and go from there. Maybe more or less alcohol depending on the air temps.

Once you start doing aero testing it's important to control external variables, remember, whatever you 'see' in the fluid when you're not moving was affected throughout the flow regime from rest to speed and back down. It may therefore not represent the actual effect you're interested in. It also only represents aero effects near the surface of your body, which is all well and good if you're only looking at high pressure attached flow regions, but will be useless visualizing detached or flow-flow interaction away from the body, for example looking at how flow around your mirrors affects flow around the side of the body and thus a rear mounted wing (for example). Once you go over the limitations of this method you'll know how to better utilize it controlling external variables...