tape off both sides (masking tape)
make your layout
jig saw with fine metal blade
block sand
reinstall

 

put tape down wherever the jigsaw foot is going to run/slide or you'll scratch

 

might even need to have a spray bottle of old soapy water on hand. from my past experience using a jigsaw to cut acrylic, it tries to melt back together behind the blade.

 

Use a medium to coarse blade. A fine blade will not cut fast enough and will cause the plastic to heat up and melt, clogging the blade up. I did mine a few months ago and posted some pics here. Also no water, it will loosen the tape and you run the risk of scratching the shield. Honestly the hardest part is drawing the line to cut. If you are keeping the same shape just use a large piece of cardboard or construction paper and trace your existing edge then simply move it down as far as you need to cut it. Good luck.

 

Leave the line so it can guide your sanding too

 

don't use a jig saw

use a die grinder and a cut off wheel. 1/16 thick works well.

yes tape both sides and a penciled line works great!

Then use a belt sander to finish it up (I use a bluepoint 1" wide one, a bench style works too)

I had an old one laying around (with scratches in it) painted the inside flat black and air brushed half the out side

 

Cool! Sounds like an easy job. Cracker I am curious about why you suggest the cut off wheel - wouldn't that be harder to control?

 

I've always used a 17 tooth jigsaw blade (medium) , and cuts right through it, with no problems.Good luck.

 

nope just go easy, I cut radius's in sheet steel all the time, I have even used it to cut vinal siding without shattering it all over

 

ya use a die grinder.. may take some elbow grease to make the top nice and smooth again. ive heard you should have a windshield about to your nose.. should be looking over not though it.