Is Silicone a Plastic? The Real Cost of Material Misclassification in Procurement

Silicon isn't a plastic. That might sound like a trivia fact, but misclassifying it cost my company $4,200 in rework and delayed orders last year.

That's the kind of mistake you only make once. I'm a procurement manager at a mid-sized packaging company, and over the past six years I've tracked every invoice—about $180,000 in cumulative spending on plastic sheets, repair compounds, and specialty materials. I've compared quotes from eight vendors, built my own total-cost-of-ownership spreadsheet, and learned the hard way that the cheapest option often isn't.

When I say I have mixed feelings about premium materials like 3M semi rigid plastic repair or Bayblend polycarbonate, it's because every spreadsheet analysis pointed one direction while my gut pulled the other. Here's what actually happened.

The numbers said go with the budget plastic repair. My gut said stick with 3M.

Last year we needed a fast-cure compound for repairing cracks in our forming dies. A generic brand quoted $8.50 per unit. 3M's semi rigid plastic repair was $12.00—about 40% more. My boss wanted the cheap one. But I'd read that 3M's formula had better adhesion to PVC (our primary sheet material) and a longer service life. I calculated total cost over one year: the generic would need reapplication every three months (four times a year, material + labor). The 3M product lasted twelve months. Total: generic $8.50×4 + 4 labor hours = $68. 3M $12.00×1 + 1 labor hour = $22. We saved 68% by going with the more expensive product. But I won't lie—the two weeks between ordering and first delivery were stressful. I kept second-guessing: what if the 3M didn't perform as advertised? (It did.)

Bayblend polycarbonate versus ABS: another gut-versus-data battle

For a new industrial housing we were tooling, the engineering team specified Bayblend polycarbonate—a PC/ABS blend from Covestro (formerly Bayer). It's about 25% pricier than standard ABS. I pulled up my cost tracking system and saw that over $180,000 of historical spending, we'd had 3% breakage with ABS parts. Bayblend promised half that. The numbers said Bayblend would save us $1,200 annually in scrap and replacement. But my gut said, why pay more for something that's already working? I went with the numbers. Turns out Bayblend's impact resistance was way better—we had zero breakage in the first six months. That's when I started building my TCO calculator.

Asbestos foam board: a hidden time bomb in procurement

Here's a weird one. One of our older clients still used asbestos foam board for insulation in their equipment (though it's been banned in most new construction since the 1980s). We needed to replace a section, but sourcing it was a nightmare—only two suppliers still carry it, both with minimum order quantities and long lead times. I spent three weeks comparing options, and the cheapest quote was still $2,300. The alternative: replace the whole panel with a modern calcium silicate board for $1,800. The client wanted the asbestos board because it matched existing specs. Honest? I had to explain the total cost included storage, handling, and disposal fees for the old board (asbestos waste removal is expensive). They finally agreed to the modern solution. My cost tracking system showed we avoided about $700 in hidden disposal fees.

3M RelyX universal resin cement: not your typical glue

While most of our spend is on sheet materials, we occasionally need a high-strength bonding agent for assembling plastic parts. 3M RelyX universal resin cement is actually a dental-grade cement, but we've found it works great for bonding PET and PVC in low-temp environments. I was skeptical at first—$45 for a 5ml syringe? That's premium pricing. But one syringe bonds about 200 small joints, versus $15 for a tube of epoxy that only does 50 joints and requires clamping. The efficiency gain was huge. Switching to RelyX cut our assembly time from 4 hours to 1.5 hours per batch. (Not that we ever get that kind of time savings from a single material change.) I have mixed feelings about the cost premium—part of me thinks it's overkill for simple applications, but the data shows it's worth it for high-volume runs.

Is silicone a plastic? (And why it matters for your budget)

Back to the beginning. Is silicone a plastic? Short answer: no. Silicone is a synthetic elastomer, not a thermoplastic or thermoset. But I've seen suppliers list it under 'plastic materials' in their catalogs, which is wrong. When I ordered what I thought was a plastic gasket (for a food-grade application), the supplier shipped a silicone gasket. It worked technically, but the price was 30% higher than the PVC gasket I'd budgeted for. I had to eat the difference—that was the $4,200 mistake I mentioned. Since then, I've updated our internal material classification system and trained our engineers to specify materials by exact ASTM type. It sounds boring, but it saves money.

When to ignore all this advice (the boundary conditions)

Every rule has exceptions. Here's when you should not follow my approach:

• One-time projects: If you'll never use the material again, the upfront cost matters more than long-term TCO. Short-term savings are OK.
• Commodity items: For standard PVC sheets where performance is identical across vendors, go with the lowest price—just verify quality with a sample first.
• Rush orders: When you need it tomorrow, you can't spend three weeks analyzing total cost. That's when relationships with reliable suppliers (like those who stock 3M products) pay off.

In the end, efficiency is competitive advantage—but only when you have the data to back it up. I've started sharing my TCO template with other procurement managers. It's basically a spreadsheet that adds setup fees, waste rates, labor time, and disposal costs to the unit price. That $10 difference in unit price often becomes a $100 difference in total cost. And that's what separates a cost controller from a price shopper.

(Oh, and if you're wondering: yes, I keep my TCO spreadsheet updated quarterly. As of March 2025, the formulas still hold.)