All projects

Transparent Light Covers

Vacuum formed clear covers for brake, indicator and running lights, sized hard against the rules to stay small, light and easy to blend into the aerobody.

Role
Mechanisms and Finishing
Date
2025
Tags
Lighting CAD Manufacturing Regulations Solar Racing

Outcomes

  • Clearer PETG replaced the old opaque fibreglass, so compact lamps stay visible without wasting power.
  • Passed lighting and enclosure checks at scrutineering.
  • Sized aggressively against the regulations, giving smaller, lighter covers that blend into the aerobody.
  • Sealed against water ingress with clean wiring and service access.

New to Solar Racing? Read What is Solar Racing? for a quick overview.

Requirements

Meet visibility cones and brightness for indicators, brakes and DRLs.
Keep covers sealed and smooth for low drag.
Allow access for service without damaging the finish.

Design

I shaped the covers in CAD to follow the shell and keep a clean aerodynamic profile. I first placed the lamps to satisfy the cone requirements, then designed the cover geometry and flanges around that. I also sized the covers aggressively against the lighting regulations: pushing the size limits meant smaller, lighter covers that are much easier to blend into the aerobody.

I compared a few manufacturing options. The goal was high optical clarity so the lamps could stay compact without wasting power. The previous car used fibreglass covers that fit the carbon shell well but were opaque. I chose vacuum forming for cost, speed and clarity, then printed several forming tools to iterate.

Front light cluster behind a clear formed cover.
High-mounted central stop light.
Left indicator cover aligned to the shell curvature.
Right indicator cover trimmed to a scribe and sealed.

Most covers formed cleanly over male moulds thanks to gentle curvature. The two rear covers were more complex and needed female moulds. I tuned the vacuum port sizes to avoid print-through while still pulling enough suction to form. Below are two tool approaches used on the rear left cover.

Prototype female mould before surface prep and port tuning.
Formed cover next to a one-piece male tool used in early trials.

The rear left was difficult because of size and shape. A male draw thinned PETG too much and it lacked stiffness. The female approach uses two halves bonded together. The split line is less transparent than a single draw, but overall clarity is still a big improvement on the last iteration.

New vacuum-formed PETG covers compared with the older fibreglass covers. Higher clarity allows lower lamp power for the same visibility.
Finished rear right light.
Finished rear left light.

Build

Covers are clear PETG, vacuum formed over printed tools. I trimmed to a scribe line, test fit on the shell, then sealed with a thin adhesive bead around the flange. I faired the outer edge into the surface with a small fillet of body filler, wet-sanded to a smooth transition, and wrapped over the area.

Materials and notes

  • PETG sheet, 1.0 to 2.0 mm depending on stiffness and curvature
  • Printed tooling with light draft and a smooth surface to avoid imprint
  • Clear structural adhesive on the flange with light clamping during cure
  • Small body-filler fillet to blend into the carbon shell, then wet-sand and wrap
  • Service access planned for lamp PCBs and cable runs

What I would refine next

  • Bond covers earlier in the build to allow more fairing time and a cleaner wrap finish
  • Use printed resin tools for the complex rear geometry to improve surface quality
  • Standardise access for PCB replacement and sealing checks
Viewer //