It bends. It does
not shatter.
Polycarbonate is what you specify when a broken panel is not an acceptable outcome. On the standard instrumented impact test, glass takes 6 inch·lbs before it fails and acrylic takes 24. Polycarbonate takes 800 — roughly 133 times glass and 33 times acrylic — and when it finally gives, it deforms instead of throwing fragments. That is the whole argument for machine guards, security glazing, and anything a person stands behind. If your drawing says Lexan, this is the material it means — Lexan is a brand of polycarbonate, the way most plastics go by a brand name.
Stock & Sizes
What we keep on the floor in Sparks
Solid polycarbonate sheet in six thicknesses, cut to size the same day. Clear carries the full range; the tints are stocked in the gauges people actually order them in. The gauges are drawn edge-on beside each size, all at the same scale.
| Thickness | Decimal | Edge on, to scale | Colors on the rack |
|---|---|---|---|
| 1/16″ | 0.0625″ | Clear | |
| 1/8″ | 0.125″ | Clear, gray, bronze, black | |
| 3/16″ | 0.1875″ | Clear, gray, black | |
| 1/4″ | 0.250″ | Clear, gray, bronze, black | |
| 3/8″ | 0.375″ | Clear, gray | |
| 1/2″ | 0.500″ | Clear |
Above 1/2″ we source to order, up to 2″. Abrasion-resistant, anti-fog and bullet-resistant grades come in to order as well. Everything on this table is cut same day — if you need a tint in a gauge that is not listed, ask and we will confirm the lead time with the price.
Looking for the ribbed insulating panel rather than solid sheet? That is twin wall polycarbonate, stocked deep in 6 mm and 8 mm — one sheet or a pallet.
Our Material: PolyGuard™ by Calsak
We buy PolyGuard because it is consistent sheet to sheet, the sign grade carries a real written warranty, and Calsak publishes full property data we can hand an engineer instead of a sales sheet. It comes in three grades, and picking the right one matters more than most people expect — the wrong grade is how a machine guard hazes over in eight months.
| Grade | What it is | Specify it for |
|---|---|---|
| PolyGuard IS SG | UV-resistant sign grade. 88% clear light transmission, 35% white. 10 year limited warranty against breakage, yellowing, and loss of light transmission. | Exterior signage and faces, skylights, canopies, glazing, anything that has to stay clear outdoors for years. |
| PolyGuard AR | Hard-coated, abrasion resistant. Taber abrasion at 100 cycles gives only 2.4% delta haze. 86% clear; brown, green, and smoke tints available. UL 94 listed, File #E331779. | Machine guards, viewing windows, safety shields, and any panel that gets wiped, scrubbed, or handled. Bare polycarbonate scratches; this does not. |
| PolyGuard IS Optics | Optical grade. 88% light transmittance with just 1.0% haze — the clearest of the three. | Instrument covers, lenses, display and enclosure windows — anywhere you are looking through the sheet and clarity is the spec. |
If you tell us the application we will tell you the grade. The most common mistake we see is a bare sheet going into a wash-down or high-traffic spot where it should have been AR, and the second most common is paying for AR on an interior part nobody touches.
Typical Properties
| Property | Test method | Typical value |
|---|---|---|
| Physical & optical | ||
| Specific gravity | ASTM D 792 | 1.2 |
| Refractive index | ASTM D 542 | 1.586 |
| Light transmission, clear @ 0.118″ | ASTM D 1003 | 88% (IS SG) · 86% (AR) |
| Light transmission, tints @ 0.118″ | ASTM D 1003 | White 35% · smoke 44% · green 42% · brown 41% |
| Water absorption, 24 hr | ASTM D 570 | 0.15% |
| Taber abrasion, 100 cycles (AR grade) | ASTM D 1003-13 | 2.4% delta haze |
| Mechanical | ||
| Tensile strength, ultimate | ASTM D 638 | 10,500 psi |
| Tensile strength, yield | ASTM D 638 | 8,700 psi |
| Tensile modulus | ASTM D 638 | 350,000 psi |
| Elongation | ASTM D 638 | 150% |
| Flexural strength | ASTM D 790 | 14,000 psi |
| Flexural modulus | ASTM D 790 | 350,000 psi |
| Izod impact, notched @ 0.125″ | ASTM D 256 | 17 ft·lbs/in |
| Izod impact, unnotched @ 0.125″ | ASTM D 256 | No break |
| Instrumented impact @ 0.125″ | ASTM D 3763 | 800 ft·lbs |
| Rockwell hardness | ASTM D 785 | M74 / R118 |
| Thermal | ||
| Coefficient of thermal expansion | ASTM D 696 | 0.000038 in/in/°F |
| Heat deflection @ 264 psi | ASTM D 648 | 228°F (IS SG) · 288°F (AR) as published — see note |
| Heat deflection @ 66 psi | ASTM D 648 | 293°F |
| Vicat softening point | ASTM D 1525 | 304°F |
| Electrical | ||
| Dielectric strength, in air @ 0.125″ | ASTM D 149 | 420 V/mil |
| Dielectric constant @ 60 Hz | ASTM D 150 | 3 |
| Dissipation factor @ 60 Hz | ASTM D 150 | 0.001 |
| Volume resistivity | ASTM D 257 | 2.0 × 1017 Ω·cm |
| Flammability | ||
| Horizontal burn, AEB | ASTM D 635 | 1 in |
| UL 94 listing (AR grade) | UL 94 | File #E331779 |
Source: Calsak Plastics published typical properties for PolyGuard polycarbonate sheet, rev. 02/10/2016, reproduced as published rather than adjusted. Where a figure runs above the general-purpose polycarbonate norm — heat deflection especially — design to the industry value and ask us for the certified number on the specific sheet. Typical properties, not specifications. IS Optics is published in metric — the grade table above and the data sheet download cover it. One note for anyone checking our math: the property table lists instrumented impact as 800 ft·lbs while the accompanying chart plots the same 800 figure in inch·lbs against glass at 6 and acrylic at 24. We quote inch·lbs, because that is the unit the comparison is actually drawn in. For a regulated, structural, or life-safety application, work from the data sheet and tell us what you are building.
The Numbers, on Charts
Straight off Calsak's published PolyGuard impact chart, drawn to a linear scale — the two small bars really are that small. Roughly 133× glass and 33× acrylic. One caveat worth stating: ASTM D 3763 is written for rigid plastics, so treat the glass bar as the manufacturer’s benchmark rather than a formal ASTM result for glass. The acrylic-to-polycarbonate ratio is the one to design against.
The abrasion-resistant hard coat costs about two points of light transmission. On a machine guard or a viewing window that gets wiped every shift, that is a trade worth making every time. White at 35% is the standard translucent sign face — it is engineered to diffuse a lamp evenly, not to see through.
Two different loads, two different numbers — heat deflection is always measured under load, so quoting it without the load is meaningless. Straight talk on these figures: they are Calsak’s published values for PolyGuard, and the sign grade and AR sheets list 228°F and 288°F for what is the same base polymer, which cannot both be right. General-purpose polycarbonate sheet across the industry lands around 265 to 270°F at 264 psi. Design to that, stay comfortably below it in continuous service, and if your application is genuinely heat-critical tell us and we will get the certified figure for the specific sheet before you commit.
Manufacturer documents for this material.
These grades come in to order. The sheet you download is the sheet we quote from.
PolyGuard™ is a trademark of Calsak Plastics. Every document above is the manufacturer's own, reproduced in full. The only thing we add is a “Distributed by” band across the bottom of each page so you know who to call locally — nothing above that line is altered, moved, or removed, and no page of ours is added in front of theirs. The SDS is passed through exactly as the manufacturer issued it, with the same band at the foot of each page and nothing else touched. Need a mill cert or a certificate of compliance for a specific lot? Ask when you order.
Where It Gets Used
Polycarbonate or Acrylic?
Impact versus appearance, and it is not close in either direction. Polycarbonate takes roughly 33 times the impact energy of acrylic and survives being drilled, routed, and cold-bent without cracking — but it scratches easily unless you buy the AR grade, and it costs more. Acrylic is clearer at 92% transmission, holds a polished edge, stays looking new longer, and machines beautifully — but it cracks. Rule of thumb: if someone could get hurt when it breaks, use polycarbonate. If it is a display, a sign face, or a cover nobody will hit, use acrylic and spend the difference elsewhere. Full side-by-side comparison with the numbers →
Fabrication
We cut polycarbonate to size, CNC rout it, drill it, and line-bend it in our Sparks shop. Two things worth knowing before you draw the part. It is hygroscopic — it picks up moisture, and it has to be dried before thermoforming or it bubbles, which is why a shop that does this regularly is worth using. And it moves: 0.000038 in/in/°F, about six times steel, so a 96″ panel grows close to 1/4″ across a 70°F swing. Build in clearance and use slotted holes, or the panel will bow or tear out a fastener within a year. Laser cutting is not recommended — it leaves a discolored, gassy edge. Saw, rout, or shear it instead.
Common Questions
How much stronger than glass is it, really?
On the instrumented impact test Calsak publishes, glass fails at 6 inch·lbs, acrylic at 24, and PolyGuard polycarbonate at 800 — about 133 times glass and 33 times acrylic. You will see “250 times” quoted a lot across the industry, usually against a different glass thickness or test. We would rather give you the number that comes off a published chart you can check.
Which grade do I actually need?
If the panel gets touched, wiped, or scrubbed — machine guard, viewing window, partition — specify AR. If it lives outdoors and has to stay clear for years, specify IS SG for the 10 year warranty. If you are looking through it and clarity is the specification, specify IS Optics. Call us with the application and we will pick it with you; it takes two minutes and saves a lot of grief.
Will it yellow outdoors?
Bare polycarbonate does. The UV-resistant grades are built for it: PolyGuard IS SG carries a ten year limited warranty against yellowing and loss of light transmission, and the AR data sheet publishes a yellowness-index curve out to twelve years against uncoated polycarbonate. Specify a UV grade for anything permanently outside, and mount the UV-protected face out.
Can it be scratched?
Yes, and this is the material's real weakness. Standard polycarbonate scratches much more easily than acrylic. The AR grade is hard-coated for exactly this reason — 2.4% delta haze after 100 Taber cycles. Also: leave the masking on until installation, and clean with mild soap and water. Ammonia glass cleaner attacks polycarbonate.
How hot can it run?
Heat deflection is 288°F at 264 psi on the AR grade and 293°F at 66 psi, with a Vicat softening point of 304°F. That is well above acrylic and far above polyethylene. For continuous service, plan on staying comfortably below those numbers and tell us the load — deflection temperature is measured under load, not in still air.
Do you have the SDS and data sheets?
Yes — all four are on this page, free to download, no form. The SDS is Calsak's document reproduced unaltered, which is how a distributor is required to pass one along. If your safety department needs a signed certificate of compliance or a mill cert for a specific lot, ask when you order and we will get it.
Can you cut it to size today?
Usually, yes. Clear and tinted solid sheet is stocked in Sparks and cut the same day, from one piece to a full sheet. Send a drawing, a sketch, or the broken original — we have made plenty of guards from the piece someone carried in. Free delivery in Reno, Sparks, Carson City, Fernley and USA Parkway.
One hour. Tomorrow. Or today when it can’t wait.
We stock it here and we run our own van. Three ways to get material — take the one you need.
