This short guide shows variants of making paper waterproof and writable. Waterproof means that the paper does not tear apart when it is wet and you write on it. (The methods also work for read-only paper.)
Waterproof paper already exists. For example, Rite in the Rain sells notebooks with waterproof paper, and other suppliers also sell waterproof printer paper. Many methods have been invented and patented.
The methods often use some of those components:
- Adhesive (acrylic polymers, polyurethane, etc.) for paper stability
- Wax (paraffin wax, natural waxes) for soaking the paper so it cannot be soaked by water anymore
- Fillers (BaSO4, TiO2, CaCO3) for different purposes – whitening, roughening, and so on
Paper is then either coated with those components, or they are added directly to the paper pulp when the paper is created.
Some papers are also made of synthetic materials instead of cellulose. They are obviously very waterproof since those materials, unlike cellulose, won’t soak with water and become soft.
Paper can also be made waterproof with some simpler DIY methods. The result won’t be as high-tech as commercial paper, which can e.g. also be laser-printed, but one can write on it even underwater.
The approach is to soak the paper with some lacquer. This works pretty well.
Other approaches have disadvantages:
- Wax (applied under heat) makes paper hard to write due to the waxy surface
- Nano covers (like the liquids used for waterproof clothes; I tested a spray from Granger’s) rely on repelling water, but do not prevent it too well from soaking, so once the paper is wet, it still tears apart.
Probably the easiest method is to use lacquer from a spray can. Apply it to one side, let dry, and then apply to the other side. The paper should become slightly transparent while spraying, and it should be covered by a thin film everywhere.
Another method, which is also bio-degradable, is using shellac. Shellac is produced by lac bugs and can be dissolved in ethanol, but not in water. Shellac is used as lacquer for e.g. violins.
When dissolving shellac flakes, cover them with the 2-fold amount of alcohol, and add more if required when everything is dissolved. The liquid should be more viscous than water, but not much. You can use a brush to apply the shellac (put the paper on baking paper or similar as pad), or directly bath it.
Note that the paper will stick when drying; I usually let it dry on top of a halfway opened book so that it only touches the cardboard binding. Or, fold a Z-shaped pillar of a thicker piece of paper.
Writing on waterproof paper
The best idea is to use a soft pencil (B or softer), or an all-weather pen. Normal ink-based pens will not work; water-based inks will just be washed away, and solvent-based inks will not write either underwater or smear on moist paper.