Finishing Acrylic Plastic

Scraping

The first step in getting a finished edge is scraping. The back of a hacksaw blade is perfect for scraping. Simply draw the corner of the square edge of the blade along the edge of the acrylic.

Filing

A 10 to 12 inch smooth cut file is recommended for filing edges and removing tool marks. File only in one direction. Keep the teeth flat on the surface, but let the file slide at an angle to avoid putting grooves in the work.

Sanding

If necessary, start with 120 grit sandpaper, used dry. Then switch to a 220 grit paper, dry. Finish with a 400 grit wet/dry paper, used wet. Grits as fine as 600 may be used. Always use a wooden or rubber sanding block.

When removing scratches be sure to sand an area larger than the scratch. Sand with a circular motion, and use a light touch and plenty of water with wet/dry papers.

Almost any commercial power sander can be used with acrylic. Use light pressure and slower speeds.

Polishing

Final polishing will give acrylic a high luster. Power-driven buffing tools are recommended without exception. Buffing wheels are available as attachments for electric drills.

A good buffing wheel for acrylic consists of layers of 3/16″ carbonized felt, or layers of unbleached muslin laid together to form a wheel. Solidly stitched wheels should be avoided.

The wheel should reach a surface speed of at least 1200 feet per minute. Speeds of up to 4000 feet per minute are useful for acrylic.

Acrylic should be polished using a commercial buffing compound of the type used for silver or brass, or you can use a non- silicone car polish that has no cleaning solvents in it.

First, however, tallow should be applied to the wheel as a base for the buffing compound. Just touch the tallow stick to the spinning wheel, and then quickly apply the buffing compound.

To polish, move the piece back and forth across the buffing wheel. Be careful not to apply too much pressure. Keep the work constantly moving to prevent heat buildup.

Never begin polishing at the edge of the sheet. The wheel could easily catch the top edge and throw the piece across the room or at you.