Acrylic vs Polycarbonate and why?

12765 Views 25 Replies 14 Participants Last post by harrysin, Nov 4, 2019

AshleyJ

Discussion Starter · Oct 7, 2019

I'm considering making my first custom sub-base for my Bosch 1617. It's less about necessity than trying something new, so I'm quite flexible.

I've read this fine thread and half a dozen others, used google to search this site, and viewed a dozen youtube videos. Everything about making sub-bases seems quite clear except this...

Key question: Do you use acrylic or polycarbonate, and why?

Bonus question: How thick? 1/2", 3/8", 1/4", other?

What's not being asked here...

I'm aware that acrylic is also known as plexiglass, plexiglas, lucite, and many other trade names. I'm aware that polycarbonate is also known as lexan, makrolon, and others. I'm not particularly interested (yet) in debating the various brands... only understanding clear acrylic vs polycarbonate, and desirable thickness.
I'm aware that a router sub-base can also be made from MDF (or almost anything else), though in this case I'm particularly interested in it being clear and easy to see through.

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Cherryville Chuck

· #2 · Oct 7, 2019

One of my kids left a sheet of something in my shop. I’m not sure what it is but I made a table plate out of it. If you are making something like an offset base then just about any plastic sheet will be okay. A table plate might be more critical where sag is possible. I manage that possibility by not leaving it in the table when I’m not using it and having made it as small as I could. You don’t want it any thicker than it needs to be. Every 16th is a 16th less reach your bit will have but usually 5/16 to 3/8 is about right.

One consideration is that some plastics are prone to crack when you torque down flat head screws so you may want to counterbore holes and use pan heads screws instead.

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kp91

· #3 · Oct 7, 2019

Cast Acrylic. Cheaper than lexan, and you can find it lots of places. If just making a sub base you don't have to be that thick. If you are making an offset base or something you might want closer to 3/8".

If drilling thin acrylic look up ways to drill it without cracking it, such as grinding back the corners where the edge of the drill bit meets the flute so it doesn't catch and crack it.

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difalkner

· #4 · Oct 7, 2019

Polycarbonate is stronger and more impact resistant. Acrylic is shinier and less expensive. Acrylic cracks easier and Polycarbonate is easier to scratch. Acrylic can be heated and bent to shapes while retaining its appearance, not so with Polycarbonate. Polycarbonate yellows over time, especially if in sunlight, but Acrylic remains clear.

There are obviously more pros/cons but this is the quick list I refer to when deciding which product to use.

David

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Stick486

· #5 · Oct 7, 2019 (Edited by Moderator)

I vote for polycarbonate... VOE...
keep in mind that acrylic is nick sensitive...

Acrylic plastic:

Less expensive than glass and polycarbonate
17x the impact resistance of glass
92% light transmittance in all thicknesses (better clarity than glass)
Insusceptible to yellowing or discoloration from the sun
Thermoplastic with a working temp of 180F continuous
Durable against scratches and dents
Sheets can be polished smooth
Easy to cut
Heat bent
Clean glue joints
Shiny surface
Large variety of colors available
Widths from 48” to 108”
Lengths from 72” to 192”
Recyclable

Polycarbonate:

250x the impact resistance of glass and 30x stronger than acrylic
Bullet resistant grades are available
88% light transmittance
Less rigid and available in a variety of flexible grades
Thermoplastic with a working temp of 240F continuous
Low level of flammability
Durable against chips and cracks
Highly resistant to acids and other chemicals such as gasoline
Sheets can be drilled without worry of cracking
Cold formed or bent without heating
Widthes from 38” to 75”
Lengths from 78” to 150”

Acrylic or Plexiglass Sheeting:
Pros:
Easier to machine than polycarbonate
Can be polished, both for scratches and clean edges
Better glue bonding
Shinier
Less expensive than polycarbonate by as much as 35%

Polycarbonate Sheeting:
Pros:
Greater strength than acrylic
More flexible than acrylic; can be shaped at room temperature
Can be exposed to high temperatures and is non-flammable
Highly resistant to chemicals
Can be drilled without cracking
Lighter in weight than comparable acrylic

Acrylic or Plexiglass Sheeting:
Cons:
More rigid
More likely to crack during drilling or upon impact
More likely to chip
Should not be exposed to open flames

Polycarbonate Sheeting:
Cons:
Scratches easily
Can be dented easily
More translucent than transparent as compared to acrylic

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TWheels

· #6 · Oct 7, 2019

One factor to keep in mind is that polycarbonate ie a polymer of bis-phenol A (bPA), and the monomer leaches out when exposed to water. bPA acts as an estrogen mimic. Hence some care is needed during working, and the waste must be carefully disposed.
On the other hand there are very few side effects of using acrylic, a polymer of methyl methacrylate. It has been used in medical implants. It seems that there are few if any risks associated with the waste beyond that of any fine particulate.

David Bradford

· #7 · Oct 7, 2019

Thanks for all that info Stick.

Stick486

· #8 · Oct 7, 2019

Bonus question: How thick? 1/2", 3/8", 1/4", other?

all of the above...

harrysin

· #9 · Oct 8, 2019 (Edited)

I prefer to use Poly-carbonate because it's tougher than Acrylics and routs without all the fluffy static laden swarf like Acrylics do. The first shot is Poly-carbonate 5mm and the second 4m Acrylic and I've had no problems with either.

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smitty10101

· #10 · Oct 8, 2019

@stick

add the chart to the addendum library????

& perhaps to a sticky in the forum since a form of this comes up regularly

smitty

Reactions: 3

Stick486

· #11 · Oct 8, 2019

smitty10101 said:
@stick

add the chart to the addendum library????

& perhaps to a sticky in the forum since a form of this comes up regularly

smitty

good plan...

Stick486

· #12 · Oct 8, 2019

smitty10101 said:
@stick

add the chart to the addendum library????

& perhaps to a sticky in the forum since a form of this comes up regularly

smitty

done...

Stick486

· #13 · Oct 8, 2019 (Edited)

Need to polish your Polycarbonate???

Have at it...

.

TenGees

· #14 · Oct 9, 2019

Ashley, I used 1/4" cast acrylic (better quality than extruded) in a router table and found that it sagged a little (see Chuck's advice above). Polycarbonate is even less stiff. I would go thicker if you're going much beyond the router base and expecting support.

Doug mentioned drilling... A guy I used to work for in the sign business would drill the concrete floor before using a new bit on acrylic. Maybe not the ideal way to handle the situation but it avoided the snagging / cracks.

As I mentioned before, I use cheap stepper bits but that might not be great for thicker plastic because of the bit-width changes (I used mostly 3/16 and 1/4 inch for signs).

radios

· #15 · Oct 10, 2019

stretched Polycarbonate is used for fighter jet canopies, as it's very tough, and because it's stretched, if hit with a bullet, it shatters into small pieces like tempered glass.. I don't remember Acrylic being used in any Military applications, so I don't think it's better..

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gmedwards

· #16 · Oct 10, 2019 (Edited)

One other thing. You can glue acrylic, by not polycarbonate. The glue is a very thin liquid and needs a special needle applicator to apply. I found the glue and applicator at a local plastics shop. Here's a link to what you need at Amazon:

https://www.amazon.com/Weld-Acrylic-Adhesive-Applicator-Bottle/dp/B0096TWKCW/ref=asc_df_B0096TWKCW/?tag=hyprod-20&linkCode=df0&hvadid=312719382368&hvpos=1o2&hvnetw=g&hvrand=8862313467348406152&hvpone=&hvptwo=&hvqmt=&hvdev=c&hvdvcmdl=&hvlocint=&hvlocphy=&hvtargid=aud-801381245258

la-404766667839&psc=1&tag=&ref=&adgrpid=63696814698&hvpone=&hvptwo=&hvadid=312719382368&hvpos=1o2&hvnetw=g&hvrand=8862313467348406152&hvqmt=&hvdev=c&hvdvcmdl=&hvlocint=&hvlocphy=&hvtargid=aud-801381245258

la-404766667839. It's been awhile since I've purchased any, but I believe was cheaper locally.

The ability to glue acrylic really expands its possibilities. As an example, several years back, I made a vacuum fence for my cabinet saw. It attaches to my Incra TS fence system. With a variable speed control on my vacuum, I can set the vacuum from light to so tight it's hard to feed the stock. It has completely eliminated kickback on my saw and ensure the stock remains tight against the fence. It's also very slick.

Gary

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Stick486

· #17 · Oct 10, 2019 (Edited)

How to Glue a Polycarbonate Sheet

Lightly (VF/XF) sand the locations where you want to glue the pieces together.
The locations should be smooth to the touch.
Clean the edges of the sheets where you want to fuse them together.
Add a small trail of methylene chloride or chloroform along one edge of one sheet.
Allow the solvent to soak into the sheet. The edge should become a little sticky.
Place the sticky edge onto the clean edge of the other sheet.
Support/clamp the sheets to keep the two edges in constant contact with light clamping pressure while the sheets dry.
Allow the two sheets to dry for 14~48 hours.
This should be done in an extremely well-ventilated area.

DO NOT FORGET to use your respirator, eye protection and rubber gloves....

http://www.wipolymers.ie/2015/05/gluing-polycarbonate-polycarbonate-glue-plastic-glue-ireland/
https://www.cyberbond1.com/adhesive-solutions/polycarbonate-adhesives/

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Stick486

· #18 · Oct 10, 2019

y'all might want to read this...

.

Reactions: 2

Stick486

· #19 · Oct 10, 2019

How to Clean Polycarbonate Sheets

How to Clean Polycarbonate Sheets

Manufacturer-Approved Cleaning Procedures for Multi-Wallcleaning-polycarbonate-sheets. Polycarbonate, Acrylic & APET

The UV-resistant surface treatment on one side of the polycarbonate sheet significantly improves long-term weatherability. Periodic cleaning using proper procedures and compatible cleaners is recommended to prolong the service life. For general cleaning, it is recommended that the following instructions and cleaning agents be used. These procedures and cleaners are also recommended for use on the untreated, interior surface of the polycarbonate sheet, and for acrylic and APET plastics.

CLEANING PROCEDURES

Rinse polycarbonate sheet with lukewarm water.
Wash polycarbonate sheet with a mild soap and lukewarm water.
Use a soft cloth or sponge and gently wash with an up and down motion in the same direction as the flutes, as shown in Fig. 1.
Rinse the cloth or sponge and change the water often. DO NOT SCRUB or use brushes or squeegees. The coating on polycarbonate sheets is UV-resistant; IT IS NOT A MAR-RESISTANT COATING.
Repeat rinse and dry with a soft cloth to prevent water spotting.

IMPORTANT: If a material is found to be incompatible in a short-term test, it will usually be found to be incompatible in the field. The converse, however, is not always true. Favorable performance is no guarantee that actual end-use conditions have been duplicated. Therefore, these results should be used as a guide only and the products must be tested under actual end-use conditions by the user.

NOTE:
I have found that ammonia degradates Acrylic and Polycarbonate's inherent UV protection over time...

Polycarbonate sheets are treated on one side for protection against UV damage. This treated side must be glazed outward or toward the light source to provide protection for polycarbonate sheet substrate.

© 2014 The Polycarbonate Store

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TenGees

· #20 · Oct 14, 2019

When putting sheets in aluminum frames, we used to put a 'hanging block' along the top and bottom edges of a face. We used methylene for acrylic but pop-rivets for polycarbonate.

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