Sanding and polishing PLEXIGLAS® for brilliant surfaces
Sanding and subsequent polishing lets rough, matt PLEXIGLAS® cut edges and surfaces appear glossy again, even scratches can be removed in this way. This guide describes the procedure as well as the tools suitable for the purpose. First, however, you should prepare your workplace and lay out all the materials required.
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No time to spare? Here are some quick tips for readers in a hurry!
- Secure the PLEXIGLAS®
- Smooth the cut edges with a scraper or hand planer
- Sand to remove unevenness
- Polish the material
- Remove residues of polishing wax or paste
Materials and tools—grinding and polishing PLEXIGLAS®
- Draw Blade
- Sanding block
- Water sanding paper or sanding net
- Cotton cloth
- Polishing paste
- Cloth buffing wheel with polishing wax
- Grinding grids
- Beaker with water
First sand, then polish
Professional tip
The choice of abrasive grit depends on the depth of the tool marks or scratches: The deeper these marks, the coarser the grit. Sanding is usually performed in several steps using an increasingly fine sandpaper.
Sanding and subsequent polishing restore a high-gloss transparent surface to the rough- sawn and matt cut edges of a PLEXIGLAS® sheet. PLEXIGLAS® can be sanded by hand using sandpaper.
In mechanical sanding with, for example, rotating grinding discs, orbital sanders, or belt grinders, the grinder should be moved gently - do not press on the PLEXIGLAS® sheet too hard or too long as the resulting heat of friction may cause stress and surface damage. Important: Regardless of whether sanding is manual or mechanical, PLEXIGLAS® should always be wet sanded to avoid thermal stress in the workpiece and clogging of the abrasive paper.
The Machining PLEXIGLAS® brochure tells you what to look out for during the process.
Various methods
Various methods of polishing are available:
- manually, with polishing paste and a cotton cloth
- polishing with a cloth buffing wheel and wax
- polishing with felt tape and wax
- flame polishing
- diamond polishing
Polishing with a cloth and polishing paste is a commonly used method. An alternative that is equally suitable for both DIYers and professionals is polishing with a cloth buffing wheel. On the other hand, polishing with felt tape, flame polishing, and diamond polishing require some experience and special tools.
The Machining PLEXIGLAS® brochure tells you what to watch out for in the process.
How to grind and polish PLEXIGLAS®
Instructions: Sanding and polishing PLEXIGLAS® cut edges
1
Secure the PLEXIGLAS® sheet
Secure the sheet to a base using clamps or screw clamps, or a vice with protective jaws, so that it does not slip. Ensure that no sharp-edged parts project from the base, these could damage the material.
2
Smooth with scraper
Start by smoothing the cut edge with a scraper (shopping-cart symbol). Guide the scraper over the edge several times using moderate pressure until marks or scratches are no longer visible.
3
Sand with water sanding paper
Sand the cut edge with water sanding paper using a little water. Start with a coarse sandpaper and repeat the process with successively finer grits; the sandpaper used last should be very fine, possibly with a grit as high as 1000. A sanding net can also be used for this process.
4
Apply polishing paste
Apply polishing paste on a soft cotton cloth or the sanded edge and rub in the paste with moderate pressure. Repeat the process until the required polishing quality is obtained.
5
Remove excess paste
Finally, thoroughly clean off excess paste using a cloth and water.
Instructions: Polishing PLEXIGLAS® surfaces with a cloth buffing wheel
1
Secure the PLEXIGLAS® sheet
Secure the sheet to a base using clamps or screw clamps, or a vice with protective jaws, so that it does not slip. Ensure that no sharp-edged parts project from the base, these could damage the material.
2
Clamp the cloth buffing wheel in the drill
Cut edges, as well as relatively large and curved surfaces, are easily polished with a cloth buffing wheel clamped in a commercially available drill.
3
Apply polishing wax
Make sure that the cloth buffing wheel is free from old wax. Apply the new polishing wax on the rotating disc.
4
Polish PLEXIGLAS®
Switch on the drill with the cloth buffing wheel before starting to polish. Move the cloth buffing wheel with light, uniform pressure over the edge or the surface. The rotational speed is determined by the size of the buffing wheel. If this has a large diameter, set a low rotational speed; if the diameter is small, a high rotational speed is recommended.
5
Remove polishing wax
At the end of the process, remove excess wax with a dry cloth.
Tips and additional notes for sanding and polishing PLEXIGLAS®
- Be careful to remove dirt from materials and tools beforehand so as not to damage the acrylic.
- Wrap the sandpaper around a wooden or cork block to grind the PLEXIGLAS® cut edges.
- Do not press down with the polishing tool at any one spot of the material too long or with too much force.
Sanding and subsequent polishing can be used not only on cut edges but also to restore heavily scratched or scuffed surfaces. Note that the polishing of small areas, particularly if these have been sanded beforehand, changes the surface due to abrasion of material and such areas remain clearly visible.