Cutting Acrylic Plexi

Tighe

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I picked up a piece of acrylic plexi to replace the plexi protecting the control panel overlay on my Marvel Vs. Capcom cabinet.

My experiece has been that cutting plexi can be dangerous, if you are not careful CRACK!

My thoughts on how to cut it:

1. Go at it carefully by hand with a hole saw.

2. Use the old plexi as a guide (stencil, template) and use a scribe to slowly etch the holes.

3. Do the same thing, but use a tiny dremel bit.

Opinions?
 
Just take it to the hardware store. I took a piece to a "Do-it" Hardware, and they cut it for free on their machine.
Edit: I didnt read the whole post. They wont cut holes, just straight lines. Id use a hole saw bit and a drill and take your time.
 
I use a 60 tooth carbide tipped blade in my table saw for straight cuts and a holesaw (the kind that have an arbor and mound in your drillpress or hand drill). To keep from cracking it I normally drill the hole part way through, flip it over and drill from the other side. It's when the hole saw breaks through that most cracking occurs. This way the holes meet in the center where the plexi is the strongest and I rarely crack it anymore.

ken
 
if you take the new plexi and sandwich it between two pieces of wood then place the old plexi on top of the top piece of wood as a template you can just drill through the wood and the plexi with a hole saw and it won't crack. A paddle bit will also usually work but has a slight bit higher risk of still damaging the plexi.
 
The one time i had to drill threw plexi with a hole saw, after i first started with a pilot hole, I ran the drill in reverse and melted threw the plexi with the hole saw. then cleaned that up with a razor knife and the edges of the holes were covered by the buttons that went into those holes.
 
I use lexan and a laminate trimmer bit. Works perfect and lexan does not crack.
 
Having a large bit dig into the plexi, whether with a hole saw or not, is what cracks it. I always mounted or clamped the plexi to the control panel, then inserted the hole saw without the drill bit into the hole in the control panel and cut the hole in the plexi. Some hole saws don't have removable bits in the mandrell though. In that case, run the drill in reverse until the bit melts through. If centering the hole is a problem, start with a small bit and use progressively larger ones to get to the desired size, but always run them in reverse except for the smallest two or three sizes.
 
+1 on the laminate trimmer with a flush cut bit. You can use double stick tape to stick it to the control panel and use the laminate trimmer to cut off the excess. As far as holes go, just but a unibit or similar stepdrill and drill a hole in the center of each hole location and use the laminate trimmer to trim out the rest. - Barry
 
if you take the new plexi and sandwich it between two pieces of wood then place the old plexi on top of the top piece of wood as a template you can just drill through the wood and the plexi with a hole saw and it won't crack. A paddle bit will also usually work but has a slight bit higher risk of still damaging the plexi.

1+ This is the way I go after many different attempts. I ended up making a metal "C" shape jig when I had to drill ~100 holes to mount plexi panels. No other way to drill without cracks propigating from the drilled hole.
 
I've never had a problem drilling through Plexi. My table saw has holes on the top. I just position the circle for the hole I want to drill over one of those holes and go through it with a hand drill and hole saw. Haven't had a problem yet. I let the hole saw work it's way through and not push down on the drill. I would assume trying to push the drill through would cause the plexi to break.
 
I'll clarify in that I'm speaking of actual drilling procedure rather than a cutting action like that of a hole saw. The plexi likes to follow the bit up the shaft and slam back down when it reaches the chuck, this impact and calked hole / bit is what cracks it every time... The wood plates , jig, or whatever just keeps it from going up the shaft when it catches on the flutes of your bit.
 
How thick plexi can you cut with the laminate bit?

It depends on the flush cut bit. Most of the bits I've seen can cut up to 3/4 inch but you should go slow at that thickness. 1/4 inch or thinner is no problem at all. - Barry
 
It depends on the flush cut bit. Most of the bits I've seen can cut up to 3/4 inch but you should go slow at that thickness. 1/4 inch or thinner is no problem at all. - Barry

Flush trim bits rule for plexi and lexan- it goes through it like butter. I drill a pilot hole the size to fit the trim bit through and then I open up the hole with the trim bit using the old cp hole as the guide for the bit. Amazingly accurate and clean. Just beware of freakin' hot plexi flyin' everywhere.
 
OK it's done!

I picked up one of those laminate trimmer bits and used a router. It worked great, you just have to be very careful of the height, I cut a little extra in a couple places, but they are covered by the buttons. My router's height slips so I had to keep adjusting.

Here is the bit:
dscn2320.jpg


I drilled holes 1/4 inch the same size of the bit. You can see a hole that was routed in this photo:
dscn2321.jpg


It is important that the bearing line up with the original plexi:
dscn2322.jpg


Here it is installed, looks so much better than the cig burns and spider crackes!
dscn2323.jpg


Hard to really see ing photo, here is an angled shot:
dscn2324.jpg


The only downside of this method is that the bit was $25. But I am sure I will reuse it in the future.
 
Looks really nice, glad that it worked out well for you. Maybe it's just the angle but does the P2 stick go all the way into the down position w/o hitting the edge of the plexi? Again, probably the angle, but the stick looks a bit off-center.

*e* Did my own plexi cutting last night, had to shave about 1/4" off the 24x24 smoked panel that got here for the 6-1 I've been putting together. Tried scoring it but it was taking too long, went with a hand-held hacksaw which did the trick, as I don't have a table saw and I figured taking that small an amount off wasn't worth finding a friend with one. Amazing the amount of control you have with those things, though I still wound up with a bit of a rough edge. No big deal, as that edge was close enough and was up against the side of the cab so it doesn't really show. When I got done with that, it fit width-wise, but I wasn't able to push it up into the top to clear the CP. Like an idiot, I went "oh well, better cut 3/4" off the bottom to fit it". Got about 3" into that cut and double checked the cab, realizing that there isn't a support across it on the top and it was just flexing a bit. A jiggle later and I was good to go. On the bright side the part with the cut in it is fully covered/supported by the control panel, so I doubt I'll have a cracking issue and it looks great. I'll put up pictures at some point.

The important lesson I did learn in the whole process (other than always wear shoes sitting in an office chair, opened up a hole in the back of my heel by way of being clumsy) was with the scratches left from the scoring attempt. If you take a black sharpie and run it down the scratch in a one or two inch pass then immediately wipe the surface with a paper towel, it fills the scratch and the paper towel clears up most of the ink around it. I wouldn't do it in a spot over the monitor, but for small scratches in smoked that are showing white off to the side you don't see them unless you're right up on it with a flashlight after that.

Sorry for the thread hijack, but figured an existing post about plexi would be a good place to drop a tip that really isn't worth it's own thread. :)
 
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