The pace picked up as the weather improved. I focused on stripping the paint and getting the parts prepared for painting. Everything is plastic on the R75/6 except the gas tank which is steel. So, sandpaper is your friend 🙂
I found that sanding the short radius curved areas first prevented rounding off the profiles. I used wet/dry paper and wet sanded to help the paper last longer. I dipped the paper in water and cleaned out the paint accumlulation from the paper frequently so it continued to cut quickly. As soon as I could see a good deal of paint flakes in the water on the parts, I’d wipe it up with rags so the paper wasn’t resanding removed paint flacks.
Brian told me to use 2 strips of paper, folding them in half, then inserting them so the seams are opposite each other. For sanding flat surfaces, this gave me four sanding surfaces and I got two strong edges for sanding the grooves and tight radius contours. With the paper wet, having the rough side of the paper under myu palm helped keep my hand from sliding off the paper. Go slow in the tight radius areas and contours to keep the edges crisp and avoid rounding them off. In the tighest areas, I used a small flat blade screw driver to crack the paint off. The blade is thicker than the paint scraper so it doesn’t gouge or scratch the plastic.
I wet sanded using 220 grit to start. I stripped the clear coat, color coat and primer coats until I started to take off the next to last primer coat. Then, using 400 grit, I stripped the next to last primer coat. This left a smooth surface so hopefully I won’t have as much sanding to get the new primer coats smooth. We shall see.
I found a used R90S bullet fairing with mounting hardware and windscreen on eBay for a good price, so I picked this up and added it to the stack of parts to strip.
I saved the gas tank and subframe for last and used aircraft stripper to get the paint off. I found that process was less labor intensive than sanding. I found it took several applications of the stripper following each with a paint scrapper to get the loosened paint off. The color coats and top primer coats would bubble up, but the lower primer layers required use of a paint scraper to get them off as all the stripper would do was soften them, not lift them.
After the paint was removed, I took a dremel tool to grind out any cracks that had developed in the plastic parts. Then, I used fiberglass resin to fill in the ground out areas so they won’t crack again. Any cracks will grow cracking the pain. The other impact is they also will soak up the paint and develop blisters, so you need be sure you get all of them ground out and filled.
After the resin had cured, I sanded the area where fibreglass resin had spread on the surface near the crack. Then I used spot putty to fill in low spots and to smooth out and level the fiberglass resin filler in the cracks.
You need to keep the putty layers thin. It usually hardens in about 3o mins. I lightly sanded with 400 grit to smooth it out and if I needed another layer, added it. This part of the prepartion is fussy work, but getting the surfaces smoothed out as much as you can goes a long way to having a high quality paint finish, so take your time.
I had a small crack in the dashboard of the R90S fairing between the cutouts for the two instruments. Again, I used fiberglass resin on the back to fix the crack. I found the fairing had been painted over the top of the original paint, so there was a lot more sanding required. Along the seam at the bottom of the wind screen the paint build up was quite thick so I took it down to the plastic using the folded sandpaper sandwich.
I estimate it took me about 30 hours to do the preparation for two fenders, two side covers, a gas tank and the bullet fairing. Patience is a virtue when it comes to preparing parts for painting. By the way, your finger tips are very sensitive and good measuring tools to feel high and low spots. Use them to check your spot putty filled areas as you sand them. If you can’t feel the edge you have it feathered into the surrounding surface correctly.