Plexiglass windows anyone?

[Pamela H]

Ok...they are driving me crazy. We are replacing the large window in the back, the frame is out, and we are trying to cut the plexiglass. HELP!! Done a few test cuts, the only thing that seems to be working is a small hand saw. Everything else is breaking/splitting the plexiglass. We even tried scoring it...but that won't work on the curves. I am thinking straight cuts and then sanding down with a dremel tool?

Pam

[Kevin K]

Try a very fine cutting blade and run cold water on the cut when cutting.

[Rick Helgren]

You may want to try applying masking tape over the cut mark prior to cutting.

[Martin D]

Ok...they are driving me crazy. We are replacing the large window in the back, the frame is out, and we are trying to cut the plexiglass. HELP!! Done a few test cuts, the only thing that seems to be working is a small hand saw. Everything else is breaking/splitting the plexiglass. We even tried scoring it...but that won't work on the curves. I am thinking straight cuts and then sanding down with a dremel tool?

Pam

There are special inexpensive scoring/cutting tools available for this type of plastic. Available at Home Depot / Lowes in the section where they sell the plastic. I tape a metal ruler / yardstick 36" or longer to the plexiglas on the cut line with masking tape . Make multiple scores or cuts along the rule edge on the plastic to achieve a square piece of the correct size. After obtaining a square, cut the round corners with a Dremel tool and fine sand the edges with 80 to 100 grit sandpaper. You have to make multiple scores or cuts before breaking the cut line (better too many than not enough). Best method to break is to lay the piece over a 1/4" dowel beside and underneath the score line and press down on the adjacent piece not supported by the dowel. Martin

[Pamela H]

There are special inexpensive scoring/cutting tools available for this type of plastic. Available at Home Depot / Lowes in the section where they sell the plastic. I tape a metal ruler / yardstick 36" or longer to the plexiglas on the cut line with masking tape . Make multiple scores or cuts along the rule edge on the plastic to achieve a square piece of the correct size. After obtaining a square, cut the round corners with a Dremel tool and fine sand the edges with 80 to 100 grit sandpaper. You have to make multiple scores or cuts before breaking the cut line (better too many than not enough). Best method to break is to lay the piece over a 1/4" dowel beside and underneath the score line and press down on the adjacent piece not supported by the dowel. Martin

Do you flip the piece over and do both sides? Or can you score just one? We do have the scoring tool from home depot...

[David Joseph]

I score both sides. I've had plex splinter badly too many times not to. Never had a problem when both sides are scored, and you've got a head start beveling the edge.

[Lisa H.]

I always score and tape as well. I usually don't have any problems cutting when I use my orbital jigsaw with a fine blade.

[Harry Young]

I would purchase a cut out tool...they are cheap and work like a router, I incl a link, never had a failure with this even with Lexan. http://www.harborfreight.com/cpi/ctaf/disp...temnumber=42831

You can also melt thru it, albeit slow and then sand the edge...I do the first suggestion.

Harry

Ok...they are driving me crazy. We are replacing the large window in the back, the frame is out, and we are trying to cut the plexiglass. HELP!! Done a few test cuts, the only thing that seems to be working is a small hand saw. Everything else is breaking/splitting the plexiglass. We even tried scoring it...but that won't work on the curves. I am thinking straight cuts and then sanding down with a dremel tool?

Pam

[Capt Ron]

Cutting plastic depends on the type of plastic to some degree. Acrylics can be scored and cracked, Polycarbonate is better off machined. Plastic shops can provide cutting tools for either and most such shops will cut to size and finish the edges. Acrylic material is much more brittle than polycarbonate and very subject to cracking. Polycarbonate on the other hand, scratches easier because it's softer but it is very much tougher (this what is marketed as bullet proof). Minor scratches can be buffed out of acrylics but not polycarbonate (it's too soft). Polycarbonate won't shatter and it's easier to machine but thicker materials won't yield to the scoring method unless you score them very deeply.

You might try cutting with a high-speed spiral cutting tool. They make the spiral bits for Dremel or routers. I have had success cutting 1/8 material with one. Another idea might be to use an abrasive blade in a table saw or skill saw (metal or masonry cutting blades might work) although I have cut polycarbonate with a carbide toothed blade in a table saw. You can also get abrasive coated blades for a sabre saw. You could cut the panes over sized, say by 1/8 inch and then trim them to size using a counter-top laminate tool in your router. This would remove the edge chips and finish the edge.

In any case the cut edges will benefit from machining the edges. A very small round-over bit in the router is best but a bevel edge or sanding smooth is better than nothing. Especially with acrylic material, a tiny chip can lead to the whole pane cracking right across. The machining or sanding removes these small fractures. A professional shop would flame treat the edges to achieve the same thing.

Drilling these products also requires special care. Plastic shops sell specialty drill bits but the main issue is allowing the drill bit to cut through the material. Putting too much pressure on the bit usually results in the last few thousandths of thickness to break through, leaving small fractures around the edge of the hole. These small fractures will result in a cracked pane eventually. Drilled holes should always be treated with a high speed countersink to bevel the edges. The holes don't need much of a bevel edge just enough to remove the tiny chips.

Whatever you do, wear glasses and be careful.