You came here for the details. Here ya go - It amazes me how many people call me and ask me for exact way on how to use a preval sprayer for gel coating. Initially I tell our fans to watch the video's that are posted on our youtube site as they give a good tutorial but people want more info. I don't blame them.
Here is a recipe that was sent to me that i think is great! This shows you the whole gelcoat process and why the Preval is the best method!
Side note: I prefer Styrene over Acetone for a thinning agent.