A. General Comments
1. Reasons, Means and Targets:
The final step in fabrication, finishing improves both the practical and esthetical properties of PALSUN sheet prior to assembly.

2. Grinding & Polishing:
This is mostly done as a part of edge preparation.
Practical objective: Rough, uneven, untended edges may be starting points for crazing and cracks after the PALSUN sheet is installed and subjected to day by day exposure to wind loads, UV radiation and thermal expansion & contraction, not to mention man-made punishment.
Aesthetic objective: Nicely finished, smooth edges are a must for a quality appearance of the finished product, often installed with exposed edges.

3. Decorating:
A type of finishing intended mostly for aesthetic appearance or for display purposes. Executed by painting, printing, films or hot stamping.

B. Grinding / Sanding
General: A primary stage in edge finishing, rough or gagged edges and cutting tool marks created by a saw, shearing machine or a router, can be removed by grinding.

Grinding / Sanding Recommendations:
A belt sander, equipped with a 400-500 grit belt, running at 20 - 30 m/sec (65 - 100 ft./sec), is the preferred option, applying low contact pressure during operation. Wet sanding and waterproof belts are preferable, as they prevents heat buildup, sanding dust accumulation, and prolong sanding belt life.

A reciprocating or orbital sander can also be used, but it can be applied only by the dry sanding method.

Manual Sanding can also be used, wet or dry, working with successive grit size abrasive paper (at first 100, then 280-grit silicon-carbide, and finally 400-600 grit sandpaper).

C. Polishing
On the progressive stage in edge finishing, the sanded (or ground) edges are polished to a smooth finish.

1. Basic Polishing:
It is done by abrasive-charged revolving wheels, made of cloth, leather or bristles. When used with a coolant, peripheral speeds of 10-15 m/sec (30-50 ft./sec) are recommended. When the wheel is operated dry lower speeds should be used.
Ashing: A polishing method in which wet rubbing compound like #00 pumice is applied to a rotating loose muslin wheel. Higher peripheral speeds of 20 - 22 m/sec (50 - 70 ft./sec) can be used, as overheating is not a problem in this technique.
Buffing: A finishing step in which grease or wax filled abrasive bar is applied to rotating muslin wheel. Loose buffs are used for irregular shapes or for entering crevices. Usual buffing compounds are tripoli, rouge or other fine silica.

2. Advanced Polishing:
It is achieved by using flannel or chamois wheels, with wax compounds with the finest abrasives such as whiting or levigated alumina. The wax fills the fine scratches or imperfections and protects the polished surface.

3. Final Polishing:
For removing even the minute scratches remaining and achieving a slick, glossy edge finish, solvent finishing with MEK or Methylene Chloride can be used.
a. (Recommended) A small container with the solvent is heated to about 40°C (104°F) and the vapor created runs out through a rubber hose, and is passed over near (about 50 mm or 2 in. distance) the roughly polished edges. A small amount of vapors is enough to achieve highly glossy edge surface. A repeated application is possible if required.
b. (Optional) A cloth soaked with MEK or Methylene Chloride, run carefully over the edges, can also produce acceptable results.
c. To minimize humidity blush after drying, add about 10% of a slow drying component (such as diacetone alcohol) to the basic solvent.
d. A note of precaution: when working with volatile or toxic solvents appropriate ventilation and respiratory protection are cardinal.