Restore the clarity of acrylic and polycarbonate plastic parts such as boat windshields, port-lites and hatch covers with 3M Plastic Reconditioning Systems, The 3M Plastic Reconditioning System Charts will assist you in determining which procedure and products you need for your plastic reconditioning project.
Prior to the start of your plastic reconditioning project, refer to the following helpful hints.
(Plexiglas, Acrylite, etc.)
Because acrylic plastic has a greater surface hardness than polycarbonate plastic a simple scratch test can be performed. Find an inconspicuous area of the plastic part, (i.e. corner of a windshield, area underneath a removable trim piece), where a scratch can be put into the plastic without it being noticed. Use a sharp instrument, like the blade of a screwdriver and run the corner of the blade across the plastic. If you hear a scraping sound and/or feel the blade jump across the surface, you are working on acrylic plastic.
(Lexan: Tuffak, etc.)
For testing the surface of polycarbonate plastic use the same scratch test as for acrylic plastic. If no sound is heard while scraping and/or the blade of the screwdriver moves smoothly across the surface. (denting the surface instead of scraping) you are working on polycarbonate plastic.
Polycarbonic Plastic Repair
Machine Glazing, periodically, will keep the finish in top shape. If a light scratch should occur, wet sanding with Micro Fine 1200 grit could be utilized. (Wet sanding tips below) Always have a good flow of water to help reduce clotting of the abrasive, which could actually leave the surface scratchier than anticipated. Then proceed with the machine compounding and then machine glazing.
Warning: Never use heavier than 1200 grit wet abrasive on
Polycarbonic Plastic. It is doubtful you will
ever get a like new finish if the scratch needs
more than 1200 grit.
Acrylic Plastic Repair
Here again machine glazing periodically should maintain the finish. If a small or large scratch should occur abrasives in the 600 to 320 could be utilized. Always start with the lightest that you think you will need. No sense in working more than you need to. (See sanding tips below.) Then progress to the finer grades in steps. The more steps the better and always keep the water flowing. Then machine compound and machine glaze to finish the job.
Cross-sanding is the technique of ensuring the removal of a coarse scratch by sanding perpendicular to the coarse scratch with a finer grade abrasive until all the sand scratches are in the same direction as the finer abrasive scratch. Cross-sanding will allow you to see any of the coarser sand scratches you may have missed while sanding with the finer grade abrasive prior to the compounding step.