Low heat on a smooth (very fine grit) sanded surface would probably be your best bet. Could also paint it white and then just gently cover the purple with covering over the paint?The air brakes for the plane are made from G10 Fibreglass plate. I tried to cover the G10 plate with UltraCoat and it did not work well. Would not stick well and hundreds of air bubbles. not sure how I am going to do this or just leave them as is. I can paint the white section but not the smoked purple do not have that colour.
Let me know how it works out. Same as you 3 & 4 great ran true just not the 5 inch ones Got 3 all not great.Try spinners from EF. They come pre-balanced. I have a bunch of the 3" ones and a 4" one and all have run true. Will be picking up a 5" soon for my 104" Extra 260 rebuild.