We are often asked how to attain (or restore) a smooth, gloss finish to the surface of a casting made from a Crystal Clear urethane plastic and offer the following buffing technique using progressively finer grit sand papers and sanding gels to improve surface finish.
Every casting surface is different. For surfaces that have severe imperfections, you may need to sand with coarse grit sandpaper prior to moving onto the finer grit grades. If this is the case, we suggest starting with 120 grit followed by 220 grit and then proceed to using finer grit grades (see Step 1 below).
Begin by sanding the abraded surface that you wish to restore with fine grit sandpaper (320 grit) until any prominent protrusions or grooves are removed.
Next, sand with finer grit sandpaper (400 grit).
Follow with ultra-fine grit sandpaper (600 grit).
Note: Water may be used with ultra-fine grit sandpaper to reduce particle clogging on the sandpaper and minimize heat buildup.
Next, sand with super ultra-fine grit sandpaper with water (800 grit). After this step, there should be no visible scratches and the surface should appear smooth and translucent.
This step is optional. If there are still some scratches or fine imperfections present, you can polish with Novus™ # 3 Heavy Scratch Remover and rinse under water. Dry off casting to inspect surface.
Finish with a final polish using Novus™ # 2 Fine Scratch Remover, and rinse under water. Dry off casting to inspect surface. Repeat final polish until surface is perfectly clear.
For Novus™ Plastic Polish products, visit www.novuspolish.com
Important: Results may vary due to a number of variables such as configuration of the casting, quality of the original casting, etc. As a result, Smooth-On can not guaranty or warrant that the above procedure will work for everyone. A small test on a non-critical area of the casting or different casting will be an indicator of whether or not this procedure will work for you.