You want to cover both sides of the visor with masking tape to avoid scratches & slips... Use the blue painters type, which is easier to remove when your done.
The cutting wheels are definately the best way to go for cutting long egdes, even the regular thin ones work fine. I'm assuming you have the disk mandrel for your dremel, it's the straight shank with a screw at the end. all 6you do is remove the screw, put it through the hole in the center of the cutting disk, then thread it back onto the post. Then chuck it into your dremel like any other bit. #1 tip, Be Gentle! The regular disks are VERY fragile, & will shatter if twisted or bent, or even screwed on to tightly... Take your time, & practice on scraps first... Also, you don't want to go to slowly on your actual cuts on plastic, as the friction from the disk will melt the plastic instead of cutting it, making a real mess...
I nees to cut the ends off my visor. Can I use my dremel with a diamond bit? I don't have any reinforced cutting wheels, I'd use the regular ones, but I can't figure out how to put them on.
And is there anything I should do to avoid cracking the visor?