When to Use This Checklist

This is for anyone placing orders for industrial rubber or plastic parts — O-rings, gaskets, hoses, tarps, food-contact plastic components — from a supplier like Trelleborg or through a distributor. I've been handling these orders for six years (started in 2019), and I've made enough mistakes to justify writing them down. The tally so far: roughly $8,000 in reorders, expedited freight, and one very awkward production delay. Below are the seven checks I now run before every purchase order. It takes about 20 minutes. It has saved me more than that.

One thing before we start: this checklist is for standard and semi-standard parts. If you're ordering custom-molded rubber or a non-standard polymer blend, most of it still applies — but you'll also need a materials person in the room (more on that at the end).

The 7-Step Checklist

Step 1: Lock the material spec in writing

"PP" or "rubber" on a PO is not a spec. It's a category. Before anything else, get the exact material grade, hardness (Shore A or D), color, and additive package confirmed in writing — not just in the catalog description.

The question is polypropylene PVC free comes up more than you'd think. Virgin PP is PVC-free by definition, but recycled PP can be contaminated, and some "PP blends" add PVC or other polymers to tweak flexibility. If your application touches food, medical, or potable water, ask for a material declaration — not a verbal "yeah, it's fine." I once ordered what the catalog called "food-grade PP" spatulas (plastic spatula, scraper style, for a client's food prep line), and what arrived was a PP/TPR blend. TPR is fine for general use but not for direct contact with fatty foods under our client's compliance rules. That order was $1,200 and never left the warehouse.

Checkpoint: material grade + hardness + color + additive/declaration all confirmed on paper.

Step 2: Verify brand markings and certifications

If you're buying Trelleborg or another branded product, check that the brand marking (the trelleborg logo, part number, lot code) is actually on the item or its immediate packaging. Counterfeits exist, and even legitimate distributors sometimes mix stock from different sources.

Ask for the certificate of conformity or a copy of the relevant standard (ISO 9001, NSF 61, FDA 21 CFR 177.2600 — depending on the part) and check the issuing body and expiry date. I learned this in 2021 when a shipment of O-rings arrived with a logo that looked slightly off. The font weight was wrong. Turned out to be gray-market stock — not counterfeit, but not traceable to the manufacturer's warranty either.

Checkpoint: brand marking verified against spec sheet; certificate on file with valid dates.

Step 3: Confirm hose pressure and temperature ratings

For trelleborg industrial hoses (or any brand), the spec sheet should list working pressure, burst pressure, and temperature range — separately for the tube and the cover. Don't assume the fittings match the hose rating. They often don't.

In February 2022, I ordered 200 meters of hydraulic hose rated -20°C to +80°C. Fine in summer. But our warehouse isn't heated, and that January hit -28°C for three nights. The cover cracked on about 40 meters before it ever saw pressure. That was $1,450 in scrap plus a two-day production delay. Now I check the cold-flex rating, not just the operating temperature — and I write the storage conditions into the PO.

Checkpoint: pressure, burst, and temperature range confirmed; fitting rating matches hose rating; storage conditions written into the order.

Step 4: Nail down tarp weight and coating on the PO

"Heavy duty rubber tarp" is marketing language. A PO needs weight (oz/yd² or g/m²), base fabric, coating type (PVC, neoprene, EPDM), and UV resistance if it's going outdoors.

I still kick myself for the 2020 order where I accepted "24 oz equivalent" over the phone. What arrived was 18 oz. It looked fine on the roll. It failed in six weeks. If I'd written the number into the PO, I'd have had grounds to reject it. Instead I ate the $890 and rewrote our template. The template now has a rule: if it's a number, it goes on the PO.

Checkpoint: weight, coating, base fabric, and UV rating all on the PO — not just in an email thread.

Step 5: Check food-contact compliance for plastic parts

Any plastic component that touches food — spatulas, scrapers, cutting boards, conveyor parts — needs a Declaration of Compliance (DoC) citing the relevant regulation (FDA 21 CFR, EU 10/2011, or your local equivalent). Get the DoC before the PO, not after.

This is the step where I see the most shortcuts. "It's just a plastic spatula, what could go wrong?" — well, the colorant can migrate, the plasticizer can leach, or the part can be the wrong hardness for the cleaning chemicals your customer uses. I don't have hard data on how often this happens industry-wide, but based on our own order history, roughly one in fifteen food-contact plastic orders comes back with a compliance question. That's not a rate I'm comfortable with.

Checkpoint: DoC on file; regulation cited; part number matches the DoC, not just the product family.

Step 6: Request a physical sample

This is the step most people skip. A sample costs $50–150 including freight. A wrong production run costs ten to fifty times that. Ask for a sample from the actual production batch (not a "lab sample"), and check it against your spec sheet: dimensions, hardness, surface finish, color.

I can't tell you how many times the sample has caught a mismatch that the drawing didn't. Last year we ordered a custom gasket profile; the sample was 0.4 mm off on the sealing lip. The supplier blamed the drawing (fair enough — it was a bit ambiguous). We would have caught it at incoming inspection anyway, but that's a three-week delay we didn't need. (Note to self: redraw that spec with proper tolerances before the next order.)

Checkpoint: sample checked against spec; deviations documented; supplier confirms whether the sample matches production intent.

Step 7: Write acceptance criteria into the PO

Every PO should specify: AQL level, sampling plan, what counts as a defect (dimensional, cosmetic, functional), and what happens if the lot fails (rework, replacement, credit). Add an inspection window — 5 to 10 business days is typical — so you're not stuck accepting a late-arriving defect.

This clause has saved me twice. Once for a batch of industrial hoses with inconsistent branding, once for a tarp order where the coating weight was 10% under spec. Both times the supplier replaced at their cost because the PO was specific. If it had just said "heavy duty," I'd have been arguing on the phone for a week.

Checkpoint: AQL, defect definitions, failure remedy, and inspection window all on the PO.

Common Mistakes and When This Checklist Won't Help

A few things I still see (and occasionally still do):

  • Relying on the catalog description. Catalogs are marketing. The spec sheet is the contract.
  • Skipping the sample to save time. A sample adds 3–5 days. A reorder adds 3–5 weeks.
  • Assuming the distributor knows the application. They know the product. You know the application. Spell it out — probably twice.
  • Treating "equivalent" as a spec. It isn't. "24 oz equivalent" is how I lost $890.

One honest limitation: this checklist is built for standard and semi-standard parts — seals, hoses, tarps, basic plastic components. If you're ordering custom-molded rubber or a non-standard polymer blend, the checklist still applies, but you'll also need a materials engineer in the loop. I'm not a polymer scientist, so I can't speak to long-term chemical compatibility or custom compound development. That's a different conversation, and it's one I'd rather have with someone who does it for a living.

Also — and this is the part people don't like to hear — a big brand like Trelleborg isn't always the right fit. If you need 50 pieces of a custom seal for a prototype, the minimum order quantity and lead time will probably push you toward a local job shop. Trelleborg's strength is breadth (EPDM, silicone, TPU, PTFE, HNBR, and so on) and engineering support for production-scale orders. For small-batch or one-off work, a regional fabricator is usually faster and, frankly, easier to deal with. Knowing which situation you're in is Step Zero — and no checklist will do that for you.

The checklist takes 20 minutes. The mistakes it prevents cost days and thousands of dollars. Run it before the PO, not after the rejection.