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Adjustable support for angled plexiglass laminating plates

Context

The goal was to build a support for laminating carbon-fibre fins using available wooden planks. The support needed to hold two plexiglass sheets with an included angle adjustable between 20° and 30°.

No stand was built or tested during the conversation. The dimensions and thickness of the sheets, curing pressure and temperature, and whether the assembly would act as a mould or a press were not specified.

Advice received

The suggested design was an adjustable wooden A-frame or V-shaped cradle with:

  • a stable base;
  • two end supports establishing the plate geometry;
  • removable stops or braces for repeatable 20°, 25°, and 30° settings;
  • an angle finder or inclinometer for checking the included angle;
  • end bracing to prevent spreading or twisting during lamination; and
  • a compatible release film, such as PET or Mylar, protecting the working faces.

An adjustable structure would allow the geometry to be reused and tuned for different fin profiles. Fixed wooden wedges could provide simple, repeatable settings; a locking brace could provide continuous adjustment.

If curing pressure were applied, the supporting structure and backing would need to carry and distribute the load instead of relying on the plexiglass sheets alone.

Editorial notes

  • The original response proposed attaching hinges and screws directly to the plexiglass. Drilled holes and concentrated fastener loads can create stress concentrations and cracking. A safer structure would continuously support each sheet on a wooden panel or frame and place the hinges and braces in the wooden structure.
  • Holding two plates at an angle does not by itself guarantee uniform laminate pressure. The pressure method, backing stiffness, and support geometry must be designed together.
  • The specified 20–30° is the included angle between the two plates. In a symmetric stand, each plate would be inclined by half that amount relative to the centreline; its angle relative to a horizontal base depends on how the stand is oriented.
  • Any PET or Mylar release film needs compatibility testing with the selected resin and cure schedule.

Open design inputs

  • Plexiglass length, width, and thickness.
  • Required supported span and permissible deflection.
  • Whether the angle must be continuously adjustable or only selectable at fixed values.
  • Clamp, weight, press, or vacuum-bag loading arrangement.
  • Resin system, cure temperature, and any post-cure.
  • How excess resin will be contained without bonding the laminate to the support.