Silicone vs Non-Silicone Pile Weatherstrip: How to Specify

Published 2026-10-11

Silicone and non-silicone pile weatherstrip are separate product lines, specified separately, quoted separately, and ordered separately. Among XINHAI's official product lines are silicone bristled weather strip (siliconized, hardened pile), silicate weather strip (siliconized), and non-silicone sealing weather strip. All three use polypropylene (PP) yarn. This guide covers silicone-treated PP pile weatherstrip, one product type buyers may mean by "silicone weather strip." It does not cover solid silicone rubber seals. The difference between the first and third lines is a specification decision, not a quality tier, and it should be made the same way any other line item on a drawing is made — deliberately, in writing, before the RFQ goes out.

This article is about how to make that decision defensibly. The short version: follow your drawing and your customer's specification. If the drawing says silicone, order silicone. If the drawing is silent, do not guess — flag it, ask the factory to quote both options, and get the choice confirmed in writing. Everything below explains why that procedure matters and how to run it across the other variables that travel alongside it.

What "Siliconized, Hardened Pile" Means as a Specification Line

When a drawing or specification sheet calls out "siliconized, hardened pile," it is naming a product line, not describing a chemical treatment in detail. XINHAI lists this as the silicone bristled weather strip (siliconized, hardened pile), and it lists the silicate weather strip (siliconized) as a separate line. Both sit on the silicone side of the specification divide; the non-silicone sealing weather strip sits on the other.

What matters commercially is that the wording on the drawing maps cleanly to a line the factory offers. "Siliconized, hardened pile" is the manufacturer's description of that line. Use the manufacturer's product designation on the RFQ, and confirm what "siliconized" and "hardened" mean for the selected product, including any applicable acceptance requirements. Note that "Silicate weather strip" is XINHAI's catalogue designation; confirm the product's treatment rather than inferring its composition from the name.

Two practical points follow from this:

• The silicone option and the non-silicone option are both current, orderable product lines. Choosing one does not mean asking for something unusual or custom.
• The wording on your specification should match the wording the factory uses, so there is no gap between what is drawn and what is quoted. If your drawing says "siliconized," write "siliconized" on the RFQ. If it says "silicone bristled," use that.

Do not treat the line name as a marketing term to be substituted with a near-equivalent. Treat it as a part number level of detail.

The Decision Rule: Follow the Drawing and the Customer Specification

The decision rule for silicone versus non-silicone is procedural. For purchasing against an approved specification, follow the stated treatment. If treatment is unspecified, the responsible specifier should select it against the application requirements and approve it before ordering. It is this:

1. If the drawing or the customer's specification states silicone, specify silicone.

2. If the drawing or the customer's specification states non-silicone, specify non-silicone.

3. If the drawing is silent on the treatment, do not fill the gap by guessing.

The third case is where specification errors often start. A buyer looks at the application, decides what seems appropriate, and writes a treatment choice onto the RFQ that never appeared on the drawing or in the customer's documentation. The order ships against that invented line item. If the customer later inspects against their own drawing, the treatment on the goods may not match what their specification actually required — and the buyer has no documented basis for the choice.

The correct handling of a silent drawing is to say so explicitly and get both numbers. Write on the RFQ: "Treatment not specified on drawing — please quote both silicone and non-silicone options." Then take both quotes back to whoever owns the specification. That could be the customer, the architect, the fabricator, or your own engineering contact. Let them decide, and let the decision be recorded before the purchase order is issued.

Flagging the omission during quotation gives the specifier an opportunity to resolve it before production.

Note what this rule does not do: it does not rank the options. This article does not rank the options; they are alternatives on a specification line. Your job is to match the line, not to improve on it.

Treatment Choice Never Substitutes for Correct Dimensions

The most important thing to understand about the silicone versus non-silicone decision is that it is orthogonal to fit. Fit is determined by the A–G dimensions, especially A, B, C, and D — the treatment decision is a separate line item:

• A — Base Width: 4–25 mm
• B — Pile Height: 5–20 mm
• C — Base Thickness: 0.8 mm ±0.15 mm
• D — Pile Width: state the tier (e.g. 3P2L, 4P3L)
• F — Strip Length: customized

If the pile does not fit the kerf, no treatment selection will rescue the installation. Fit comes first. Get the A–G dimensions wrong and the order is wrong, whether it is silicone or non-silicone, fin or plain, adhesive or not.

This is why sample verification matters before committing to a production run. Order samples in the actual profile dimensions you intend to use, and check the fit in the actual frame or sash extrusion. If you are undecided on treatment, sample both options at the same specified dimensions. Using the same nominal dimensions helps compare the options, but verify each sample's fit, sash operation, and required sealing performance in the assembly.

A related error: a buyer samples a profile, confirms the fit is good, and then changes the treatment on the production order, assuming the dimensions carry over unchanged. The sample the customer approved and the goods that ship are now two different line items, and if the customer's documentation was written around the sampled item, that difference needs to be reconciled in writing. Confirm the full specification on the PO, including treatment, not just the dimensions.

Silicone, Fin, and Backing Are Independent Line Items

Treatment is not the only variable that gets collapsed or assumed. Specify treatment, backing, fin configuration, and dimensions separately, and confirm that the requested combination is available:

• Treatment: silicone (siliconized) or non-silicone — confirm each option for your exact specification
• Backing: adhesive backing or non-adhesive
• Profile: fin or plain — and if fin, fin material is plastic or fabric; fin height is same as / higher than / lower than the pile height
• Dimensions: A–G (base width, pile height, base thickness, pile width tier, strip length; base margin width varies — confirm with the factory)
• Material: PP yarn

Each of these is a separate decision. A specification can call for silicone with no fin and adhesive backing, or non-silicone with a fabric fin and no adhesive, and so on. None of these choices implies any of the others, and none of them should be inferred from the application type.

The practical risk is the silent assumption. A buyer reads "adhesive" on a drawing and assumes the fin question is settled too. Or the drawing mentions a fin and the buyer assumes a material without checking whether the drawing specifies plastic or fabric. These gaps produce the same outcome as the treatment gap: a quote built on assumptions rather than on the specification.

The fix is the same procedure. When any of these items is missing from the drawing, say so on the RFQ. Resolving missing requirements before ordering can reduce the risk of changes or rejection after production.

If you want a single habit that prevents most of these problems: read the RFQ back against the drawing, line item by line item, before sending it. Anything the drawing does not state should appear on the RFQ as an open question, not as a filled-in assumption.

RFQ Checklist

Use this list to make sure the specification you send is complete and unambiguous. Every line should be either stated from the drawing or explicitly flagged as unspecified.

• A — Base Width: state the value, 4–25 mm
• B — Pile Height: state the value, 5–20 mm
• C — Base Thickness: state the value, 0.8 mm ±0.15 mm
• D — Pile Width: state the tier, e.g. 3P2L, 4P3L
• F — Strip Length: state the required length (customized)
• Material: confirm PP yarn
• Treatment: state silicone (siliconized) or non-silicone explicitly; if the drawing is silent, write "quote both"
• Profile: state fin or plain; if fin, state plastic or fabric and the fin height (same as / higher than / lower than the pile)
• G — Base Margin Width: varies with base width and pile width; confirm with the factory
• Backing: state adhesive or non-adhesive
• Quantity: state the order quantity
• Reference: attach or reference the drawing or specification the RFQ is built from

One line on this list deserves emphasis: treatment must be written as an explicit choice. Words like "standard" or "normal" on an RFQ are not a specification, because they do not map to one of the manufacturer's official lines.

Send the completed checklist along with the drawing. If anything on the drawing is unclear or missing, ask before the quote is finalized rather than after the PO is issued.

Get a Spec Quote Against a Written Specification

The whole procedure comes down to one principle: do not let a specification gap become a production assumption. Silicone and non-silicone are separate product lines from XINHAI, alongside the silicate (siliconized) line, and the choice between them belongs on the drawing or in the customer's specification — not in a guess made at the quoting stage. When the drawing is silent, quote both options and take the decision back to the specifier.

XINHAI manufactures pile and brush weatherstrip in Jiaxing, Zhejiang, China, with more than 20 production lines, a 2,000 sqm facility, and a stated daily capacity of 300,000 meters. ISO 9001 certification was announced in company news in April 2019.

To request a quote, send your RFQ with the full specification line — dimensions A–G (base width, pile height, base thickness, pile width tier, strip length), PP yarn, treatment stated explicitly (or "quote both"), fin or plain with fin material, and adhesive or non-adhesive backing. Contact Mr. Adam Huang at [email protected] or +86-573-86779825.