Polycarbonate vs PET: What the Eaton Portal Taught Me About Choosing Clear Sheet

Every few days, someone logs into the Eaton portal and asks the same question: "PET or polycarbonate?" They look alike, both are clear, and both end up in thermoforming and packaging. But after eight years of handling custom sheet and roll orders, I've learned the hard way that "they look alike" is exactly the kind of assumption that gets you in trouble.

I'm a production planner at Eaton. I've personally made and documented 14 significant mistakes, totaling roughly $38,000 in wasted budget. Now I maintain our team's material-selection checklist so I don't repeat them. This comparison is the short version of that checklist.

What's the PET Connection?

PET (polyethylene terephthalate) is the same family as clear beverage bottles, but extruded into sheets and rolls. Polycarbonate (PC) is the tougher-looking cousin. Both can be clear, both can be thermoformed, and both are priced differently. But they're not interchangeable.

People sometimes ask whether PET is "just bottle plastic." It's the same basic polymer, but sheet extrusion changes the properties. In our shop, we run PET in thicknesses from 0.15 mm to 2.0 mm, and it behaves differently at each thickness. So don't reject it because it sounds cheap.

Here's the framework I use whenever a buyer or an OEM engineer asks: compare them on impact resistance, chemical/UV resistance, forming behavior, and total cost. If you're deciding on clear plastic for an OEM part or a printed product, those four dimensions will get you most of the way.

Impact Resistance: Polycarbonate Wins, But Check the Fine Print

Drop a piece of polycarbonate and it usually survives. Drop PET and it scratches, dents, or cracks. That's why machine guards and protective windows are almost always PC. But here's the part that surprises people: in thin film form, PET can actually beat polycarbonate on tear resistance in certain thermoformed packages. Not every time, but often enough that "polycarbonate is always stronger" is a shortcut, not a rule.

The lesson? Don't pick a material just because it sounds tough. Pick it because the specific part and thickness are tested for what they'll face.

Chemical and UV Resistance: The Dimension That Caught Me Off Guard

In September 2022, I recommended polycarbonate for a clear cover on an OEM part. It made sense on paper – the cover was going to be handled, and PC is impact-resistant. But the part was cleaned with a solvent-based cleaner every day. Within two months, the covers crazed and cracked.

I had confused impact strength with chemical resistance. They're not the same. In many cases, PET handles solvents better than polycarbonate does. And PET is generally more stable outdoors unless PC is coated with a UV additive. The so-called "tough" material can be the one that yellows fastest in the sun.

People assume the tougher-looking sheet is also the more durable one in every way. The reality is durability depends on what you're exposing it to.

Forming and Fabrication: PET Is More Forgiving

On the production floor, PET is easier to work with. It thermoforms at lower temperatures, cuts cleaner, and holds print better. Polycarbonate needs higher heat, drier material, and tighter process control. If you're ordering thermoforming film for a deadline, PET usually means faster turnaround and fewer rejects.

That's not a judgment about quality. It's a practical difference that shows up in lead times and rework rates.

Cost: The Gap Is Real, But Don't Stop at Sheet Price

Based on publicly listed prices from major online sheet suppliers in January 2025, here's the rough baseline for clear sheets:

• PET, 0.060" × 48" × 96": about $85–$120 per sheet
• Polycarbonate, same size: about $130–$190 per sheet

That's a real gap. But total cost includes cutting, setup, shipping, and the cost of failure. I've seen buyers save $40 per sheet on PET, then spend $400 on rework because the part had to handle outdoor UV exposure. The cheaper material choice looked smart until the first summer. (Note to self: ask about environment before recommending based on price.)

One more thing about cost: a buyer in Raleigh once uploaded a drawing through the Eaton portal for what he called "replacement clear covers." He wasn't sure if the originals were PET or polycarbonate. We sent samples of both, and he went with PET. It saved him money, and the part worked. That's the ideal ending. The problem case is when someone assumes "clear" is a material spec.

When You Should Stop Comparing PET and Polycarbonate

Now for the part where I admit my own limits. I'm not a materials engineer, and I don't have enough experience with nylon production to give you a fair comparison. But I know this: if your part is a gear, a bushing, a hinge, or anything that slides under load, clear PET and polycarbonate are probably the wrong conversation. You need a different material family entirely.

When someone sends us a drawing through the Eaton portal and I see a snap-fit component, I tell them to talk to our nylon production partner before we quote sheet. It's not a sales move. It's the kind of honesty that keeps customers coming back. A vendor who says "this isn't our strength" is a vendor you can trust for everything else.

My experience is based on roughly 480 custom sheet and roll orders, mostly PET, PETG, PVC, and polystyrene. If you're working with nylon production or an exotic grade, this comparison only gets you so far. That's okay—the goal is to know when to ask for help.

So Which One Should You Choose?

Here's the decision guide I give buyers, and it's deliberately not a one-word answer.

• Choose PET if your part touches food, needs thermoforming, will be printed, or will stay mostly indoors. PET covers are also a solid default for binding covers and packaging.
• Choose polycarbonate if the part needs to survive impact, high heat, or outdoor weather. Use a UV-coated grade for anything in direct sun.
• Ask for a sample test before committing to a large order. We've caught 47 potential issues in the past 18 months just by asking two questions: "What is the part touching?" and "What is the part protecting from?"

If you're looking for Eaton OEM parts in Raleigh or anywhere in the Southeast, you can reach us through the Eaton portal. Tell us about the environment, not just the dimensions. That little extra detail has saved more orders than any material chart I've ever used.

PET vs polycarbonate isn't about which material is "better." It's about matching the material to the actual conditions. I'd rather answer a few boring questions now than write another $1,900 mistake into my log.