Short answer. A Schlegel Q-LON product being offered for both timber and uPVC does not make every timber groove and every uPVC receiver interchangeable. Schlegel separates application groups for timber, aluminium, uPVC and universal surface fitting [F06], and offers distinct mounting approaches including kerf, surface and self-adhesive [F17]. If the old code, cross-section and opening-system specification do not line up, you currently have no confirmed exact fit—even when the visible bulb looks identical.
Begin with the frame and where the seal works
Capture the system, not merely the loose gasket: is it a timber casement sash, a timber entrance-door rebate, a uPVC sash, a sliding panel, or glazing edge? Note the part of the assembly that closes against the seal. Schlegel’s timber range explicitly references extruded Q-LON for timber windows with 3 mm grooves [F07]. That is a manufacturer range context, not a claim that your unknown frame contains a 3 mm slot or that every timber door uses that extrusion.
| What you see | Next evidence to collect | Why the lookalike still is not confirmed |
|---|---|---|
| A narrow routed timber rebate groove | Profile foot, groove throat, insertion direction, timber system and vintage | The specified groove is part of a particular timber construction, not a transferable uPVC dimension |
| A molded uPVC frame with a narrow channel | Full frame series, gasket position, intact receiver cross-section, service-manual drawing | The same exposed seal dome can hide a different retention lip or base |
| A flat rebate with no receiver | Photograph mounting face and any original bond/fastener evidence | Schlegel also has surface-fit Q-LON types [F08], not an invitation to substitute them for channel-retained parts |
| A moving/sliding location with bristles instead of a closed foam body | Photograph yarn, fins, backing and its sliding path | A brush pile is a distinct seal construction, not merely flattened Q-LON [F15] |
Six facts that turn a guess into a useful inquiry
- System identity: note manufacturer, model/series, nominal age and market if known; a hardware brand or old Aquamac label alone may not identify a complete assembly.
- Seal location: top, hinge jamb, latch jamb, sill, sash perimeter, meeting rail or sliding brush channel. Do not group separate seals just because they share a colour.
- Attachment: kerf/press-in base, slide-in carrier, surface bond or mechanical fixing. Never cut a new kerf to accommodate a sample.
- Original profile: front and side-on photos, especially backing and corners. If the original can be observed safely without removing it, leave it in place.
- Dimensions with uncertainty: only measure accessible frame receiver and an already-loose sample using a labelled tool. Note the unit and repeat range. Do not assume compression-gap ranges equal groove widths.
- Maker evidence: locate an original system schedule or matching product drawing with part code and mounting geometry. If only the brand's product marketing is available, the fit remains unresolved.
Interpreting legacy Aquamac and Q-LON labels
Schlegel describes Aquamac as a historical designation within its Q-LON family [F09]. That explains why old catalogues and current product pages use different names. It does not establish that the next available QL-number is dimensionally identical, a supersession for a particular sash or an authorized replacement for a specific entrance door. The existing code-reference page should remain the single owner for historical code tables and any proved code crosswalk; this page covers the no-confirmed-fit field worksheet instead.
Worked decision example (not a real matching claim)
Suppose a timber sash has a closed PU-foam-looking body with an apparently narrow insert. The local shop offers a similar-coloured uPVC strip. With no receiver width, original drawing or mounting confirmation, classify it LOOKALIKE—NO FIT CONFIRMED. Ask the door/window manufacturer for an approved service profile and a drawing of the insertion foot, then compare after the reply. If a frame already binds, do not use a thick trial seal to force an apparent close.
For commercial, fire/smoke-rated or required-egress doors, stop DIY changes and seek written assembly-specific advice. A material family page, EN performance classification or a product photograph is not an approved assembly alteration.
Original evidence and scope
- [F06] Schlegel, Q-LON Seals,
Find the right seal > categories: https://www.schlegel.com/products/qlon-seals/ (accessed 2026-10-12). - [F07] Schlegel, Timber Window & Door Seals,
Q-LON: the polyurethane foam seal for timber frames: https://www.schlegel.com/products/qlon-seals/aquamac-timber-window-door-seals/ (accessed 2026-10-12). - [F08] Schlegel, Universal Application Seals,
FAQ > universal application; no dedicated groove: https://www.schlegel.com/products/qlon-seals/qlon-universal-application-seals/ (accessed 2026-10-12). - [F09] Schlegel, Aquamac or Q-LON?,
History: https://www.schlegel.com/products/qlon-seals/qlon-aquamac/ (accessed 2026-10-12). - [F15][F17] Schlegel, Products,
Seal selection by application table: https://www.schlegel.com/products/ (accessed 2026-10-12).
Dedupe/ownership: Unlike dated existing /brand-systems/schlegel-aquamac-qlon-code-reference/, this page has no code conversion table. Unlike 69 accepted NW0148 aluminium-specific and NW0151 EN 12365-specific drafts, it claims neither an aluminium fit nor a standards table. Only final Leader may accept a separate canonical route after cross-lane and fresh-site-body check.