Fiberglass is the de-facto material for real boats; I thought it would work equally well for miniature boats. Paper Wings tells honestly how easy it is to work with.

The form

I made the form from cardboard and papier mache. The cardboard layers are horizontal, cut against a printed pattern to make the boat symmetric.

Final layer was aluminum foil. I thought it would help the mold come off: BAD idea. Instead just apply plenty of wax over the paper directly.

Fiberglassing

Equipment:

• Gas mask, 50 EUR
• Nitrile gloves, 10 EUR
• Fiberglass mat, 1 m², 10 EUR
• Polyester resin + hardener, 1 kg, 15 EUR
• Epoxy paint + hardener, 1 kg, 30 EUR

Missing from the list: topcoat/gelcoat. It really is necessary to make the surface smooth and waterproof. My hardware store didn't have any, so I used the epoxy paint. Works ok but costs a lot.

Now, it really wasn't as straightforward as it appears from the photos. More like:

1. Test over a plastic cup before the real mold. Works great (doh, plastic is not paper).
2. Fiberglass the real mold. Leaves a lot of air bubbles which supposedly are going to break the structure later on.
3. Try to remove the mold. Half of it stays behind; remove it with sand paper and get bits of glass fiber everywhere.
4. Apply several layers of epoxy paint and it hides everything nicely!