Plexiglass vs Lexan

[sofakng]

Well, I've read through the section in the Project Arcade book about covering your control panel and he briefly discusses the differences between plexiglass and lexan.

I'm wondering what the differences are, and what would be better for me?  Are they both the same price and availability?  Do I need any special tools to cut either of them?

I special ordered a 5/8" MDF board to use for the control panel, so I will need a 1/8" plexiglass (or lexan).  This will allow me to fit my 3/4" t-molding just perfectly.

So, which is better for me... plexiglass or lexan?

[Bumblebounces]

Lexan (generic name: polycarbonate) is a little more expensive but not excessively so.  I have always leaned towards Lexan because of it's resistance to cracking while being drilled or cut.  Though it CAN crack, it is far less likely to do so than it's plexiglass (generic name: acrylic) cousin.  

Other than that, it's a toss up.  The two cut with similar tools.  I used a standard table saw blade designed for wood to cut my 1/4 inch Lexan control panel cover.  Plastic supply stores like TAP Plastics here on the west coast, USA, can sell you a higher tooth count blade that will cut it better and smoother but I had no problems with what I used.  For the button holes, I used a 1-1/8 inch HOLESAW, not a "spoon", "paddle", or "speed bore" type bit.  I am thinking using these types of bits on any plastic would be a disaster.

As others have counciled, sandwiching the plastic between two pieces of wood can ease the drilling of any plastic.  Plexi is far less likely to crack that way.  Another thing I have heard is to drill with the drill set to reverse so you actaully melt through.  I've never done that but many swear by it.  Use a drill press if you have access to one.  It won't allow you to run the bit in reverse (drill presses don't have reverse), but it will give you nice clean straght holes that you can never get with a hand drill.  It will also contact the surface of the plastic squarely which can help prevent the cracking some have experienced.  If your drill has a variable speed trigger, try to start the cut on a slower speed and then increase speed.  In any case, whetehr you have a variable trigger or not, ease into the start of the cut very slowly.  A crack is often caused by the teeth of the bit sticking to the plastic it's trying to cut through or digging into only one side of a circle being cut and again sticking.

Hope this helps

Bumble

[fredster]

I cut a few holes in plexi with a spade.  The first time I did I used the ON size 1-1/8" spade.  

I always mount the plexi to the wood or metal first.  I drill the mounting holes on the edges and put at least 4 screws in.

It was ok using the on size spade drill, but one did crack.  I put the hole through the wood then the plexi first.  That cracked.

I started doing something different now.  A lot of times it's not convienent to generate both holes, especially on metal panels.  (I haven't tried the greenlee punch through yet, but that might work).

What I do now is drill through unsupported over the hole with at least a 1/2" drill, no bigger than 1" spade.  Then I come back in the hole with a drum sander on my drimmel tool.  Man, the sand paper litteraly eats the plexi.  You can go pretty fast if you want too.

When the plexi is mounted over the hole, you just use the hole as a template and keep spiraling out from the center.

When it's done, just dress up the edge a little by holding the drimmel at an angle.  Perfect holes every time.

I have never used Lexan.  I did cut the plexi on a saw with a generic blade, and it did want to "bite" it and you could hear it crunch and crack all the way down.  I feed it slow.  I think a plywood blade would have been better on it.  Lexan or Plexi.

[dabone]

I just built a control panel for a Golden Tee today and I used plexi from ace hardware.
To predrill the holes for the screws I used a 6 volt rechargeable drill in reverse. For the buttons I used a hole saw in reverse also.
And for the routing, you guessed it, ran it backwards, worked like a charm.
I just used slow and steady pressure and the bits melted thru the stuff wonderfuly.

Later,
dabone

[sofakng]

Would a forstner bit work better than a spade bit?

My 1 1/8" forstner bit finally arrived today...