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Cutting lexan for windows.

7K views 6 replies 6 participants last post by  capta1n 
#1 ·
I am going to install 1/8 clear lexan instead of the glass in a drag car project. Anyone have any tips on cutting the lexan and drilling the mounting holes. I have heard a Bandsaw or Sabre saw will work best for cutting and some type of special drill bit for making mounting holes. Any tips or advice would be appreciated so I don't make a mistake and ruin peices in the process. Thanks.
 
#2 ·
For drilling the holes, I've heard that a glass drill bit (I think they have a three prong point) and some kerosene to keep thing cool will keep the lexan from cracking. Haven't done it myself that way but the info was from a guy who used to do it as a part of his job.

The drilling difficulty I've encountered always seems to come right at the end of the process, just as the bit is going through the bottom side of the plastic. My guess is that the "corner" of the bit (where the cutting edge ends and the spiral begins) is the culprit. The edge catches metal all the time (and often causes the drill to "kick"). So the same probably happens with the plastic. Only the plastic doesn't have the strength of metal and it will crack instead of just bending or creating a burr.
 
#3 ·
I've cut using sabre saw, chop saw and table saw. For 1/8" material - more teeth is better. And on a chop saw you MUST use a backer board of some type to avoid chipping off a part of your cut. I prefer the table saw over the sabre saw. I can get nice smooth, gentle arcs but it takes practice. Entering into the material and exiting out is the part most prone to chipping off the material. Use a backer board - something like 1/4 hardboard or melamine. I have also tended to crank the table saw blade as high up as I can get it (like you were trying to cut a real thick board). This makes the angle of attack of the teeth into the plastic as close to perpendicular as I can get. Shallow blade means shallow angle of attack and more likely to chip off the plastic. And sometimes on interior arcs that are gentle I will use a hand powered pull saw (Japanese saw) over the sabre saw.
 
#6 ·
When sawing turn the saw blade backwards and cool with plain water, for drilling hone a flat on the face of the drill so it won't pull itself through...best to drill from both sides so you don't have breakthrough chipping. Another trick that works well is to drill with a tiny drill first and countersink to diameter then drill through...no chipping on a 45 degree angle countersink.

If you want a nice polished edge use a torch after sanding with 600 grit to get rid of scratches, you can also buff to get a clear edge but the torch method is faster.

Practice on a scrap piece to get an idea how fast to move the torch.
 
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