Replacing plywood with carbon fiber
Plywood is already light and very cheap, so this isn’t a simple weight win — it’s about stiffness in less thickness, moisture resistance, and dimensional stability.
Baltic birch plywood is roughly 10 GPa and only ~0.7 g/cc, so it’s already a strong stiffness-per-weight performer and costs a few dollars a board. Don’t expect carbon to crush it on price — it won’t. Where carbon earns its keep is everything plywood is bad at: it doesn’t swell, rot, or delaminate when wet, it holds tight tolerances, and a carbon sandwich reaches the same bending stiffness in a thinner, lighter package.
Because plywood is light to begin with, a solid carbon swap often isn’t worth it. A carbon-skinned foam or honeycomb sandwich, though, can match a 1/2″ plywood panel’s stiffness at a meaningful weight reduction and far better moisture behavior — which is why marine bulkheads, RV/van cabinetry, and outdoor enclosures keep making this jump despite the cost.
The default is a 1/2″ (12.7 mm) plywood panel at 12×12″. Adjust it and watch how the carbon sandwich compares on weight, stiffness, and cost.
Baseline
Carbon alternatives
Verdict: choose carbon over plywood for moisture, precision, and packaging — not to save a few dollars.
When monolithic carbon actually makes sense
- Thin parts where a sandwich won’t fit. If you only have a couple millimeters of envelope, you can’t add core. Solid carbon still trims weight — useful for moving mass (rotating, reciprocating, hand-held).
- Fastener-heavy parts. Sandwiches need potted inserts at every screw location, which adds labor and tooling. Below some part count, solid is simpler.
- Cosmetic surfaces. If the part is the visual — a dash, a body panel, a cover — solid weave is what people are paying for.
Where to buy
The calculator output is a spec, not an order. For one-off or low-volume purchases, standard composite stock distributors carry pre-made carbon sheets and sandwich panels in common sizes:
- Rock West Composites — broad selection of sheets, tubes, and pre-fab sandwich panels.
- Dragon Plate — solid + sandwich CF panels with good customer-facing specs.
- ACP Composites — sheets, tubes, raw fabric.
- Layup Parts — custom-cut composite parts on demand.