# Routing Plexiglass Advice



## rpludwig (Nov 22, 2011)

Upcoming project needs some plexiglas (acrylic sheet) routed and drilled...any tips, cautions, special bits, tools, etc? Thinking forstner bits for drilling, not sure on routing. I expect whatever I attempt will "gum up the works"!

Thanks in advance, great forum here!

Ron


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## CharleyL (Feb 28, 2009)

For drilling, regular twist bits work well if you grind a flat scrapping type edge on them. If you try to drill with the standard sharp cutting edges they will pull the work up the bit as soon as it breaks through the back of the work, and will likely destroy the work. Standard Forstner bits will do the same, but will also cause significant melting.

Routing at the slowest speed possible (8,000rpm) will work, but will likely not produce a very smooth cut. You will also get melting if you move too slow.

Charley


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## giltic (Sep 27, 2010)

I had no problem drilling it with forstner bits. For routing I was using 8mm spiral bit for metal cutting with rather high speeds (about 4 on the scale 1-5). 
Checking the Google I found very mixed advices how to route plexi - someone says you must use maximal speeds and spiral bits, others swear on low speeds. Try it on scrap and you will see it's not a big deal.
Regards


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## Quillman (Aug 16, 2010)

Don't want to burst bubbles just caution you.
 I work plastic, mostly acrylic, some PVC, PC et.al.
A bandsaw, drill, grind/sand, and rout the material.
Drilling is rife with adversity. The work can shatter, climb up the drill or melt in your face. The bandsaw is very forgiving but it has its caveats.
And routing is altogther like nothing else; usually done at 20krpm+ and always with carbide.
All operations require your attention with respect to holding the work accurately and in total isolation. A work piece has 12 degrees of freedom; the fixturing that holds the work also has its immobilization issues.
Bottomline: Consider your local resources for some hands on show & tell lest you experience nuthin' but surprises.


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## Mike (Nov 22, 2004)

Ron, I think the most important consideration is having sharp tools when working with plastics. I have cut acrylic on my table saw with no problems using a Freud red 50 tooth combination blade. To cut the 4-3/4" circles needed for the VacGuard I used a good quality Bimetal hole saw. Because of the large diameter of the hole saw I ran my drill press at the lowest speed. Light finger pressure is all that is needed; let the tool do the work! I clamped one end of the Plexiglas to the drill press table and also used my hand to hold it in place so it couldn't lift when the saw cut through. While the cut was clean there was a good amount of build up on the edge of the piece. After letting the piece cool for a minute I was able to simply snap off most of the build up. Then I used a bench top belt/disk sander to remove the rest, again with a very light touch.


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## Phil P (Jul 25, 2010)

Hi Pat

What would you advise for dealing with chip weld back?

Regards

Phil


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## Quillman (Aug 16, 2010)

With what tool for what op?


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## KenBee (Jan 1, 2011)

Do they not make router bits specifically for acrylics? I am sure I saw some during my travels around the internet. 

I have a Rockwell BladeRunner that uses jigsaw blades made for cutting acrylic and always get a nice clean cut using it. When I drill I use HSS metal drills and for large holes I use a forstner bit. So far no problems, but the one thing I do is clamp it down flat on the table so it can't climb or twist. If I am working with thin stock (1/8th or less) I sandwich it between 1/4 inch plywood there again clamping it down and I never remove the protective film or paper until I am finished.


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## Phil P (Jul 25, 2010)

Ken Bee said:


> Do they not make router bits specifically for acrylics? I am sure I saw some during my travels around the internet.


Hi ken

Yes they do. In the UK both Trend and Titman list them but surely the best known American specialists in this field are Onsrud



Quillman said:


> With what tool for what op?


Hi Pat

I was thinking about the scenario you were addressing above, i.e. edge routing of acrylic. The reason I'm asking is that your approach seems to be at odds with what I was often advised by tooling companies, that wass to slow the spindle to 12,000 rpm or so and speed-up the feed speed. The idea was to produce a definite chip as opposed to just dust and by doing so reduce the heat build-up in the waste. Either way waste extraction is a must

Regards

Phil


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## bobj3 (Jan 17, 2006)

Hi Ken


The ones I have I got from Grizzy (1/4" in size) and you can get them also in the states from,see below,one looks like a drill bit you could say and the other one looks like the Precise bits..
I'm to lazy to post the picture today and it's very cold in Denver with more SNOW, that's a 4 letter world by the way this time of the year.. .

Diamond-cut Routers

http://www.ebay.com/itm/12-16-Onsru...=200680717779&ps=63&clkid=4634917096184847385
===


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## Quillman (Aug 16, 2010)

Phil:
Nutzo.
Run at 20 - 25 KRPM and get serious chip collection right at the cutter.
You should have zero flying flakes, chips or dust.
Cutters must be sharp/new, at least with a 1/2 CD if SC, or 5/8 CD min. if brazed on carbide. Keep overhang to <1/16 x stage routing. Waste everthing down to a constant 1/16".


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## cygnus (Jan 24, 2011)

I will be starting soon on some 1/2" plexiglass for some windows. I will start by cutting out rough size (within 1/8"), then using to old windows as a templates, I will dress to size. From what I read, I will adjust to run about 20 to 25K on the router and a new carbide bit. Does anyone see a problem with this????
Thanks.


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## GulfcoastGuy (Feb 27, 2012)

Most plastics mfg's will recommend a three fluted bit. I used one from McmasterCarr #35505A65. Very good results.

 IMG_3528 by pat w1, on Flickr

GCG


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## fm1328 (May 26, 2012)

Hi Pat,
I assume " 'I' work Plastic " is you. 2 questions :
1) How thick a phenolic plate should be to hold a 6-10 Kg ( 20 Pounds ) router if mounted on a router table, 6, 9mm ???
2) Any idea how various patterns - call it inlays - are done on guitar pick guards ?
Thanks,


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## Quillman (Aug 16, 2010)

Thickness depends on the size (area) of the plate and where the hung mass is.
Smack center e.g.?
Phenolics due cup, however, unless way over rated or stressed.
The complementary routing I do is not inlay. I don't have facility with inlay or marquetry.


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