Backlit Acrylic Face Plates
How to build a professional-looking backlit cockpit panel from 3mm white translucent acrylic — laser cut, primed, painted in RAL colour, edge-sealed, and laser-engraved to reveal glowing white text.
A cockpit panel that looks the part requires more than just correct dimensions. The material, paint process, edge finishing, and laser engraving sequence all determine whether the final result reads as a professional instrument or a hobby prototype. This guide covers the complete process from CAD to a finished backlit acrylic face plate, including a multi-layer approach for panels that also carry hardware components.
CAD & Design
The multi-layer system
Cockpit panels are rarely a single sheet. Depending on whether the panel carries hardware components, the build uses one, two, or three layers of 3 mm acrylic stacked behind each other. Designing each layer as a separate body in Fusion 360 from the start avoids alignment problems later.
Layer 1 — Face plate (always present) The front-facing layer made from 3 mm white translucent cast acrylic. It carries only the panel outline and any text legends — no hardware cutouts. The white core is what glows when the panel is lit from behind; the paint on top is what gets engraved through to reveal it.
Layer 2 — Separator (when the panel holds components) A 3 mm acrylic layer sitting directly behind the face plate. Its purpose is to create depth between layer 1 and layer 3 so that hardware components mounted in layer 3 can have their nuts tightened without protruding above layer 1. Without this gap, a toggle switch nut would sit proud of the back face of layer 1, preventing the face plate from sitting flush. Layer 2 has clearance openings at each hardware position, sized so the component body passes through freely. The exact opening shape does not need to be precise because layer 1 covers it entirely; a simple rectangle around each hardware position is sufficient. No text, painting, or engraving required on this layer.
Layer 3 — Hardware plate (when the panel holds components) The rearmost 3 mm acrylic layer. All hardware cutouts live here: toggle switch holes, encoder shafts, push button apertures, and any rectangular openings for sub-panels. Hardware components are inserted from the front of layer 3 and secured with nuts on the back face; the separator (layer 2) provides the clearance depth so those nuts sit completely within the stack and do not contact layer 1. Shared mounting hole positions across all three layers are the critical alignment reference.
Designing in Fusion 360
Work on all layers simultaneously within a single Fusion 360 file, with each layer as a separate component. Project the mounting hole positions from one layer to the next to guarantee alignment.
For layer 1, sketch the panel outline and place text labels. Font choice and minimum text sizes are covered on the dedicated Fonts for Laser Engraving page — the short version is: use a condensed sans-serif at 7 pt minimum with 0.12 em letter spacing.
Export two DXF files per layer: one for the cut profile and a separate file (or separate colour layer) for the engraving vectors. Most laser cutters process colour layers as separate operations with different power/speed settings.
Panel examples
The four CAD renders below show the range of face plate designs — from a simple blank cover to a complex multi-cutout hardware panel.
The blind plate (top left) is the simplest case: no hardware cutouts, no text to engrave, just a clean painted cover. It uses layer 1 only. The gear panel and AFDS back panel both carry hardware components and therefore use all three layers — face plate, separator, and hardware plate. The main captain panel (bottom right) shows the layered profile edge visible on a fully assembled three-layer stack.
Manufacturing
Process each layer separately. They go through different steps and cure at different times.
Layer 1 — Face plate
1. Laser cut the panel outline Use 3 mm white translucent cast acrylic. Cast acrylic engraves cleaner and more evenly than extruded; the cell-cast variant has a more consistent white core. Cut the profile first, before any painting.
2. Clean Remove the protective film from both faces. Wipe with isopropyl alcohol (IPA) on a lint-free cloth. Any oil or residue from handling will prevent primer adhesion.
3. Prime Apply two thin coats of grey aerosol primer (Rust-Oleum Automotive Primer or equivalent). Thin coats prevent runs; thick coats peel when engraved. Allow 30 minutes between coats. Let cure for 24 hours before top coating.
4. Top coat — RAL colour Two to three thin passes of the target RAL colour. Common cockpit panel colours:
| RAL code | Name | Use case |
|---|---|---|
| RAL 9005 | Jet Black | 737 overhead, CDU bezels |
| RAL 7021 | Black Grey | Throttle quadrant, pedestal |
| RAL 7016 | Anthracite Grey | Centre console |
| RAL 9004 | Signal Black | General instrument surrounds |
Allow 24–48 hours full cure before the next step. Rushing this step causes paint to lift when engraved.
5. Edge sealing
This step is easy to skip and the hardest mistake to fix after assembly. Paint all four side edges with a brush — same colour or matte black. Acrylic transmits light along its length like a fibre optic. An unpainted edge glows brightly even when no text is engraved there, which looks wrong from the side and wastes LED output.
Use a small flat brush and apply two coats. Let dry fully before engraving.
6. Re-engrave
Always run a test strip on a scrap piece of the same painted acrylic before engraving the final panel. Target power: enough to clear primer and paint but not deep enough to score the acrylic surface. A visible texture on the exposed white face means power is too high — the goal is a clean, flat white surface.
Oramask before engraving. Apply a layer of Oramask 810 (or any equivalent low-tack vinyl masking film) to the painted face before running the laser. The laser cuts through the film and the paint in the same pass. When you peel the film off afterwards, it lifts all the carbon and smoke residue with it, leaving the surrounding paint perfectly clean. Without a mask, smoke embeds into the paint surface around every letter and has to be cleaned manually with IPA and a cotton bud — slow work on a panel with many labels. With Oramask the panel comes off the laser bed clean in one step.
Run the laser over the text vectors using the engraving DXF file. The laser burns through the film, paint, and primer to expose the white acrylic below. Peel the film off immediately after engraving while it is still warm — it releases more cleanly than after it has fully cooled. This exposed area is what glows when backlit.
7. Clean engraved channels Use a soft brush or short burst of compressed air to clear the carbon residue from the engraved text. A cotton bud dampened with IPA can clean stubborn residue without damaging the exposed acrylic.
Layer 2 — Separator
Cut from 3 mm transparent acrylic. The separator shares the same outer profile and mounting hole positions as layer 1. At each hardware position, cut a clearance opening large enough for the component body to pass through freely — a simple rectangle around each hardware footprint is sufficient, since layer 1 covers this layer entirely.
Selective painting with Oramask When a specific zone behind layer 1 needs to block light or show a distinct colour through translucent areas of the face plate, Oramask is the best masking material for the job. Unlike regular masking tape — which must be cut by hand and produces slightly ragged edges — Oramask is a vinyl masking film that the laser cutter can cut precisely from the same DXF file used to cut the acrylic itself. The result is a mask whose edges align to the design exactly, with no hand-trimming required.
To use Oramask for selective painting:
- Add a separate cut layer to your DXF that outlines only the zones to be masked.
- Cut the Oramask sheet on the laser at low power — enough to cut the film without cutting through the backing paper.
- Weed (remove) the film from the areas that should be painted, leaving film over the areas that should stay clear.
- Apply the weeded mask to the separator, aligning it to the hardware cutouts.
- Spray the exposed area; allow to cure fully.
- Peel the Oramask off — it leaves no adhesive residue and lifts cleanly from acrylic.
Regular masking tape with hand-cut edges works for simple rectangular zones. Oramask becomes worthwhile when the mask boundary follows a curved or complex shape, or when multiple panels of the same design need identical masking.
Layer 3 — Hardware plate
Cut from 3 mm acrylic (clear, opaque, or tinted — appearance does not matter). Hardware tolerances matter here more than on any other layer: toggle switch threads, encoder shaft diameters, and push button snap-in collars all have manufacturer-specific hole sizes — measure the components before cutting.
Deburr all hardware cutouts after cutting. A deburring tool or a few passes with a fine file removes the edge sharpness that would otherwise scratch component threads and snap-in clips during assembly.
Insert hardware components from the front face of layer 3 and tighten the nuts on the back face. The separator (layer 2) ensures those nuts have clearance depth and do not press against layer 1 when the stack is assembled.
Assembly
Stack order: Layer 3 (hardware plate, rear) → Layer 2 (separator, middle) → Layer 1 (face plate, front)
Install all hardware components into layer 3 first, tightening every nut against the back face of layer 3 before stacking. Place the separator (layer 2) over the hardware — the clearance openings should pass freely over every component body without forcing. Lower layer 1 into place last. None of the component nuts should contact the back of layer 1; if they do, the separator thickness is insufficient or the clearance openings need to be enlarged.
Fix the stack together with M3 countersunk screws from the front face so the screw heads sit flush with layer 1. Countersink the holes in layer 1 at 90°; layers 2 and 3 take standard through-holes.
LED strip behind the stack The LED strip mounts behind layer 3 in the panel enclosure — it is not sandwiched between the acrylic layers. This keeps the LED strip accessible for service and allows the three-layer panel stack to be removed as a unit.
Blind plate — simplified case A blind plate uses layer 1 only. Cut to size, prime, paint, edge-seal. No layer 2 or 3 required, no engraving unless the panel carries labels. Fasten directly to the structure behind it with countersunk M3 screws.
Electronics
LED selection
Use a warm white (3000 K) or neutral white (4000 K) LED strip for instrument panel backlighting. Cool white (6500 K) reads as blue-white under camera and looks unnatural in a cockpit environment.
WS2812B strips (addressable) allow per-panel brightness control from the ESP32. Single-colour strips with a MOSFET or transistor dimmer are simpler if the whole panel dims at the same rate.
Placement and spacing
The primary rule for even illumination: the LED pitch should not exceed the distance between the LED strip and the panel face. A 10 mm LED pitch requires at least 10 mm of depth between the strip and the back of layer 3. Closer than this and individual LED positions will be visible as bands on the panel.
For LED wiring, current limiting, and PWM dimming circuits, see the LEDs & Lighting page. The resistor values and transistor switching circuits covered there apply directly to panel backlighting.
If hot spots are visible through the panel, place a sheet of 80 g/m² white printer paper between the LED strip and the back of layer 3 — it costs nothing and diffuses the light significantly without reducing brightness noticeably.
PWM dimming
Wire the LED strip through a MOSFET (e.g. IRLZ44N) driven from an ESP32 PWM pin. This allows day/night mode brightness adjustment from the CockpitConnect flow layer without modifying any hardware.
Testing
Illumination check
Power on the LEDs in a dark room and inspect the panel from directly in front and from both sides at 45°.
| Problem | Likely cause | Fix |
|---|---|---|
| Edge glow visible from the side | Edges not sealed, or one edge missed | Add another brush coat to all four edges; re-cure |
| Bright spots behind each LED | LED strip too close to panel | Increase standoff depth, or add a diffuser layer |
| Painted areas glow faintly | Paint coat too thin | Let cure fully, add another coat, re-engrave |
| Text glows unevenly across the panel | Laser power inconsistency | Re-run engraving pass at consistent feed rate |
| Sharp line visible between engraved and painted zones | Engraving vector has gaps | Check DXF for open paths; close all contours |
Readability at distance
Stand at the cockpit operating distance — typically 55–70 cm for a seated pilot position — and check that all text labels are legible without straining. At this distance, 7 pt Eurostile Extended engraved at correct depth reads clearly when lit. Smaller text or lower-contrast colours may need a size increase.
Check both day and night modes if PWM dimming is wired: at full brightness the panel should not wash out; at minimum brightness the text should still be readable in a dark room.