Saw this on another post
http://forum.arcadecontrols.com/index.php?topic=38253.msg342690#msg342690Cutting Plexi...
To cut a straight line:
a) Scoring
- do not remove the protective paper till you are ready to mount it (or will scratch)
- put the plexi partway hanging over the edge of a workbench.
- place a board on top of the plexi right next to the edge, and clamp it down
- use a razorknife, and make several passes in a line. So that its like 1/3rd deep
- Apply downward pressure and medium speed, and it should snap just fine.
b) Router
- use a straight edge as a router guide, clamped to the plexi - and to the desk.
- cut at a smooth medium speed. Too fast may cause breakage. Too slow may cause too much melting
- If some melting has formed a bumpy edge, you should be able to scrape it off
fairly easily... esp when its still warm. You could sand the edge carfully if it were
very bad... but try not to sand the top or bottom.
- I use a 1/4" rotozip drywall bit to cut with a router and works great. Im pretty
sure any bit will be ok though, because of the shear speed that they travel at.
c) Tablesaw
- Tried this once.. while worked, caused a lot of edge chipping. Might have worked better if sandwiched between to boards.
d) Drill with drillguide and rotozip bit
- worked pretty good too. But the smalled bits are more prone to flexing and
wandering.
Holes in Plexi:
- First, lightly clamp the plexi to the control panel. Use a cloth or small pieces of
wood where the clamps touch, so that the clamps do not dig into the plexi.
- Use a drill bit and drill the holes for the bolts that hold the plexi to the panel:
1) use a drill guide or a drill press. If theres any wobble, it will cause a break.
2) use a very high speed forward rotation.
3) Sink into the plexi downward at such a slow speed that it may take 30 seconds
to go all the way through. The high speeds will help to create heat and will melt as you are removing the material.. but if you go down too quickly, the material is
too brittle and will chip and or crack.
Note: Some recomend driving the drill in reverse. I tried that and had bad results. The drill bit dosnt remove the material this way, and can bind up.
Ohh, and if possible, use nice new sharp bits.
4) scrape the melted edge formed with your fingernail and it should come off easy.
5) Put bolts in and tighten them lightly. Not too tight, else they will crack. Just snag.
6) If there is enough bolts, you might be able to remove the extra clamps. Though it still may be better to leave them just in case.
7) Prepare for larger holes using the same technique. Do not get too excited and
or impatient.. and press downward too quickly. Be patient. Take a few breaks
instead.
8 ) Use one of these:
A) Spade Bits
- These have a round end that turns to a large flat cutting edge. They
make a nice hole, and they are cheap. A must: You NEED to use a drill guide
or a drill press for these. They cut very fast in wood.
b) Fostner Bits
- These make the BEST smoothest holes with no edge burrs. Cuts slower in wood. Very expensive, but so worth it. Can find a great set at harbor freight for about 35$.. other places are about 50 to 80$ for the set.
c) Hole Saws
- Ive used bi-metal holesaws for button as well. The work ok. But you have to keep removing the little plexi circles that get stuck in them. They cut slowest in wood. The are also fairly expensive. They can get hot and bind up at times in wood if you do not remove the dust. They seem to dull fairly fast. The advantage, is that you do not need the drill guide or drill press to use them.
d) circle cutter device
- these can work well for larger holes. But.. you need a drillpress to use them. The weight causes a wobble that would crack plexi easily. Even with a drill press.. all has to be clamped down very well... and work ultra slow to cut.
e) Router
- could be used to cut holes, but I advise against it. Cause first, youd need to
make pilot holes to get the bit into. Then youd need to make a near perfect
circle else the button will not fit smoothly in. However, larger trackball holes
are perfect to cut with the router.
f) Nails with string (scoring large holes)
- Ive seen some examples where people used a simple nail... tied a string to it...
popped that in a cented hole.. then attacked another nail to the other end of the string... and slowly made circles by scoring with the nail. Never tried it myself.
btw: Never use a Jigsaw! lol That will crack your plexi for sure.