Carton 100mm f/13 "MD" OTA Construction - Preparing the Main Tube - Sanding (Fine Grit)
 

Fine grit sanding of the main tube. (Click to see an enlarged image)

 
Final sanding was done using a ScotchBriteŽ pad, which is essentially a 600-grit sanding media. The pad produced exactly what I was looking for, I nice smooth matte finish. I could have gone further with finer grits, but that was not necessary. All I was trying to do was produce a smooth uniform surface to which to apply my primer and paint. Upon closer inspection, I believe you will fine that I have achieved just that.