Plexiglass cutting trouble, need advise

[MrBond]

Just got back from Home Depot and purchased a plexiglass cutting knife, some roto-zip bits, and plexiglass sheets.  (actually, the 2 plexiglass sheets were free.  hum...$30 for a sheet of Lexan, or no charge for as much plexi/acryllic (the stuff in the blue wrapping) as I want...)  Just ask if they have any "scraps".

Anyway, I tried scoring a "test piece" and started breaking it over a countertop.  However, it didn't break quite along the line and I now have some pieces that are sticking out of my straight line looking a bit like a mountain range.   .  What's the problem?  Should I score more times/press harder?  I'm using 1/8" plexiglass.

The guy at Home Depot suggested the roto-zip bits.  He said I could use them in a normal drill or even a router.    I'm thinking of mounting the plexglass to my CP top (with screws and finishing washers), and then just going around the whole thing with the drill/router with one of these bits, and then using them for the button&joystick holes on the inside.  Does this sound right?

Any suggestions/comments on how to go about this?  What have others done?  Am I making any sense?  Thanks for the help, this message board is great,

~Mrbond

[ZaneMn]

Yeah,  when your cutting plexi you've got to score the hell out of it.  When I score the stuff I usuallt dont stop until I cut all the way through in some places.  The trick to cutting plexi is to start slow and use little presure with the cutter untill you have a nicely defined groove going.  Only then do you start to really apply presure and dig into the plexi with the blade.  Nothing pisses you off more when your scoring and you accidently slip scratching your plexi!

[aj6500]

I used a circular saw set just deep enough to penetrate the bottom of the glass.  Then I clamped it onto a piece of scrap mdf so the glass was fully supported through the cut.  You end up with a slight groove in the mdf, and the glass chipped a little at the start and end of the cut.  Otherwise it worked pretty good, especially since you don't see the edges on my install.

[MrBond]

Well, I got my two marquee holders cut fairly well, and the basic outline of my CP top.  

However, still have the rounded corners and button/joystick/spinner/trackball/anlog joystick holes to drill.
Anybody try the roto-zip thing with a drill?  I'm planning on cutting this weekend, so any suggestions are appreciated!

[anthony691]

I used my router and spiral saw w/ great results.

[StingMe]

Yeah, those cheap plexi cutters don't seem to work very well...I ended up using a flush trim router bit to do the job. I think it's best to get the general size/shape cut by Home Depot or the like (to make things a bit more manageable). I secured the plexi to my CP top and then timmed the plexi with the router - plexi "snowflakes" were everywhere, but the end result was a nice clean edge. The rounded corners of your CP should be no problem. You could even take it one step further and finish off the edge with a roundover or chamfer bit, depending on how/if the edge is exposed.

This method can also be used to make the marquee sandwich or clean up the cuts made by the Depot.

As for the button/joystick/spinner/trackball/anlog joystick holes - if you've already made the holes in your CP then you can secure the plexi to the CP, drill some "access" holes in the plexi and then use the router bit again. I used a drill press to make most of the holes in my CP and just drilled through the plexi and particle board at the same time - worked like a charm.

Good Luck!

[BobA]

On scoring plexi MORE IS BETTER.  Using a metal straight edge and many passes gives a deep enough score to give a clean snap.

I tried a rotozip bit in my dremel which spins quite fast.  I used the speed control on my dremel and you can make cuts but they are not very well controlled as the dremel jumps around a bit and is hard to control.  I attached a router plate on the dremel and it became much easier to control as it worked just like a rotozip with this attachment.

I only use the dremel in confined areas where I cannot use my router or for rough cutting plastic such as the shell of a monitor that needs ventilation or a part removed.

I would guess that in a drill being held freehand it would be hard to control just as it was using my dremel freehand.  The disadvantage of using a rotozip bit is that it does not have the bearing to guide it that a flushcut bit  on a router does.  This means that it can cut the side of the control panel as well as the plexi because the cutting edge is resting against both.

BobA

[MrTeamWork]

Is it possible to cut through plexi with a circular saw going at full speed?
 I don't have a plexi cutter  - I don't even know what it is. =/

[anthony691]

On scoring plexi MORE IS BETTER.  Using a metal straight edge and many passes gives a deep enough score to give a clean snap.

I tried a rotozip bit in my dremel which spins quite fast.  I used the speed control on my dremel and you can make cuts but they are not very well controlled as the dremel jumps around a bit and is hard to control.  I attached a router plate on the dremel and it became much easier to control as it worked just like a rotozip with this attachment.

I only use the dremel in confined areas where I cannot use my router or for rough cutting plastic such as the shell of a monitor that needs ventilation or a part removed.

I would guess that in a drill being held freehand it would be hard to control just as it was using my dremel freehand.  The disadvantage of using a rotozip bit is that it does not have the bearing to guide it that a flushcut bit  on a router does.  This means that it can cut the side of the control panel as well as the plexi because the cutting edge is resting against both.

BobA

All I can say is that my router literly give it a LASER STRAIGHT edge! I didn't have quite so perfect results with my spiral saw, but it was okay.

[BobA]

A plexi cutter is a very sharp hooked edge knife that scores the plexi and allows you to snap the plexi at the score mark to make a straight break.    

Agreed that a router is the best for cutting the plexi but I think that alot of people are looking for alternatives. If you are only maing straight cuts a plexi cutter can do a good job.   I think that what some people do not do is place the scored plexi on a flat surface when they try to snap it on the score line.  If you put it on a table edge with the score on the edge and apply pressure it snaps very cleanly.  A sanding wheel or belt can be used to clean the edge or make rounded corners.

BobA

[BobA]

Mr TeamWork

If you use a circular saw on plexi you might destroy the plexi completely.   If however you have a very fine blade and can just score it you might get away with making a straight cut.  Probably not the best way to go.

BobA

[anthony691]

Yeah, I don't care how fast the circular saw spins; DONT EVEN TRY!

[RandyT]

Professional plastics outfits cut plexi with a tablesaw.

The secret is to use a good blade with 100 or more carbide teeth and put it in the saw backwards.

YMMV!

RandyT

[MrBond]

I did a lot of cutting today!!!  Wow, I think it looks great, and I didn't even remove the stuff from the protective wraps!  
I cut the control panel's basic shape the day before with the plex-glass cutter.  (followed your advise and made many scores, going almost right through).
I bought a flush trimming bit with a 45 degree angle to it.  I mounted the plexi to the CP and routed right around it.  Snow flakes everywhere...but it went very smoothly!  I was surprised and proud!  I flipped the thing over and used the holes in the cp as guides for the plexi, but I just used the same hole saw I did for the wood.  Again, it went quite smoothly.
The trackball and spinner holes were a bit more tricky, but not too hard.  The router with a flute bit and some sand paper did the job.

(Also routed out the joystick, spinner, and trackball bases while I was at it!)

Wow, can't believe how much I got done!  Thanks for the help.
Next step:  find some place to print the artwork and marquee I made/downloaded.  Quick question:Do I just lay the artwork down and then cut the holes out with an exacto-knife?  Do you glue it down?

Thanks again Arcadelites,
~Mrbond

[deadhead]

Using plexi glass I found it easiest to lay the cp on it and trace it. Then use a jigsaw and over cut just slightly keeping the cut line close to the work surface as you cut(very important). Sandwich the plexi between the cp and a scrap piece of mdf and clamp them together. I used a 1

[anthony691]

Next step:  find some place to print the artwork and marquee I made/downloaded.  Quick question:Do I just lay the artwork down and then cut the holes out with an exacto-knife?  Do you glue it down?

Thanks again Arcadelites,
~Mrbond

Well, I can't say what is best, but I can say what I did; I just layed the art between my CP and my plexi and cut out the holes very carefully. Mine wound up looking totally swankadelic so I don't think you should have any worries.

I decided it was not fair to show my MAME cabs to anyone until they are all FULLY complete; here is a glimpse at my CP with it's SWEET CP underlay! (you can expect *ALL* of the pictures from *ALL* of my cabs before weeks end!



Oh, it's just so beutiful [drool] (maybe I just feel that way because it is mine)

[deadhead]

Beautiful underlay, what program did you use? Can you offer any tips on the look you got? That

[anthony691]

Beautiful underlay, what program did you use? Can you offer any tips on the look you got? That

[deadhead]

I'll start looken' thanks