In this tutorial, you will learn to create a DIY fairing compound by using phenolic microballoons and epoxy resin. This technique is often used by professionals but can be replicated more affordably using magnesium-silicon aka talcum powder; to achieve similar results.
Tutorial by fiberglasssite.com/
So where is the prep? How much of the microspheres, how much resin? I have never seen brown microspheres. Always white. What’s the desired consistency? How are the two materials mixed together? How was the surface prepared?