Master Cutting Plexiglass with a Circular Saw
Cutting plexiglass can seem daunting, but with the right circular saw and technique, you can achieve smooth, professional cuts.
Getting the Right Circular Saw and Blade for Plexiglass
Not all circular saws and blades are created equal when it comes to cutting plastic sheets. To avoid cracking, chipping, or melting the plexiglass, you'll need:
- A circular saw with enough power (aim for at least 15 amps) to cut through plexiglass cleanly
- A specialty plexiglass cutting blade, like a Diablo Ultra Fine Finish blade with 60 teeth , designed for smooth cuts in plastic and plexiglass
Standard wood or metal cutting blades may be too aggressive and cause splintering. The right plexiglass circular saw blade will have a high tooth count, made from high speed steel, and engineered specifically to cut plastics cleanly.
Choosing the Best Circular Saw
Look for an average to high-powered circular saw in the 15+ amp range when cutting plexiglass with a circular saw . Higher amperage means more torque to cleanly slice through thick sheets. You'll also want variable speed control to customize blade speed for the material. Models with laser guides can help you follow cut lines precisely.
Finding the Right Plexiglass Cutting Blade
A 60+ tooth carbide blade made for fine cuts in plastic is ideal, like the Diablo Ultra Fine Finish series. The higher tooth count creates less friction against the plexiglass to minimize melting, chipping, and cracking. Carbide construction stays sharper for cleaner cuts in plexiglass and acrylic as well.
Preparing the Plexiglass Sheet
Before starting any cuts, you'll need to thoroughly prepare the cutting area and your plexiglass sheet:
- Cover your workspace with cardboard or plywood to prevent scratching
- Clamp a straightedge guide to use as a guide for straight cuts
- Place the plexiglass sheet on foam or wood scraps to dampen vibration
- Mark your cut lines with a scribe, marker, or masking tape
Securing the Plexiglass Sheet
One of the keys for a clean, straight cut is securing the plexiglass so it doesn't shift or vibrate. Place your marked plexiglass sheet on layers of rigid foam insulation or plywood layered in between pieces of scrap wood. The makeshift sandwich will keep the sheet stable for precise cuts.
Marking Cut Lines
Use a ruler or straightedge to mark your cut lines before running the circular saw. You can use sharpies, grease pencils, masking tape, or scoring tools to mark the plexiglass. Allow space on each side of the line for the blade kerf and inaccurate cuts.
Cutting the Plexiglass Sheet
Once your saw is equipped with a specialty plexiglass cutting blade and your sheet is prepped, you can start cutting:
- Adjust blade depth so it barely cuts through the sheet
- Line up blade with cut marks using the edge guide
- Make several slow passes at full blade speed
- Support plexiglass as it separates to prevent cracking
Blade Depth and Multiple Passes
Set the spinning saw blade so it just kiss cuts through the plexiglass thickness. With each pass, lower it fractionally until you cut through the full depth. Making several slow passes gives you better control and minimizes chipping.
Cut Speed
Maintain full blade speed as you push the saw slowly and steadily along cut lines to avoid friction and binding. High blade speed will mean faster cutting times, while lower RPMs provide more control through the cut.
Supporting the Cut
As the two cut pieces of plexiglass start separating, gently hold them together or lay them flat to prevent stress cracks. If you let separated pieces flop over, shock and vibration can cause cracks.
Additional Tips
Employ these extra pointers for flawless, smooth cuts in plexiglass:
- Use cutting lubricant like Johnson's Paste Wax to reduce blade friction
- Stack separated plexiglass pieces flat to prevent cracks from shock
- Sand cut edges lightly with 220 grit sandpaper for transparent smoothness
Cutting Lubricants
Wax or oil lubricants minimize friction and melting during cuts. Apply a light coat along cut lines before starting your pass. This allows the blade to glide smoothly through the plastic.
Sanding
Although your specialty plexiglass blade leaves smooth edges, light sanding ensures seamless transparency along cut lines. Gently smooth edges with 220 grit sandpaper.
Safety Considerations
Use extreme care when cutting plexiglass with a circular saw to avoid accidents or injury:
- Wear eye protection, respirators, gloves, long sleeves, closed toe shoes
- Avoid binding the blade to prevent kickback
- Ensure your work area is free of clutter and cords
- Work outside or use vacuums/fans for fume extraction
Preventing Kickback
Binding the circular saw blade increases the risk of violent kickback. Allow the spinning blade to cut through the sheet without forcing or twisting the saw. Also check that scrap plexiglass pieces aren't pinching the blade from behind.
Controlling Dust
Use dust collection methods like vacuums, along with proper masks or respirators, to control plastic dust and debris when cutting plexiglass sheets . Fine particulate matter can cause respiratory irritation without proper protection.
Troubleshooting Problems
Avoid these common cutting mistakes for smooth edges:
- Rough cut edges - Lower feed rate, ensure sharp blade
- Chipping - Decrease blade speed, add lubricant
- Cracking - Support workpiece fully, change blade
- Melting - Improve cooling, lubricate cuts, adjust speed
Rough or Incomplete Cuts
Ragged, rough cut edges often stem from trying to cut too quickly or using a dull, damaged blade. Slow down your feed rate and ensure your circular saw has a sharp blade.
Cracking and Chipping
Small cracks and splintered chips along cut lines come from excessive vibration, high blade speed, or dull cutters. Use proper support, lower RPMs, switch blades, or apply lubricant.
Excessive friction from unsuitable blades or too high feed rates can melt edges when cutting plexiglass sheets . Improve cooling, use lubrication, and find the right speed for clean cuts.
With attention to detail, the proper circular saw setup, and some practice, you'll be doing perfect cuts through plexiglass sheets.