Makes sense. Glutinous rice flour is the principle ingredient of wall paper paste in Asia, which is used for everything paper-related, even making furniture. It's very hard. Not as waterproof as shellac, but a lot better than plaster. They don't mention an antiseptic in the article, though. I've had paste mold because I didn't add
enough or the moisture content was too high. Flour, a little sugar, water, and antiseptic. But it needs to be boiled. You'd need a huge pot for an application like that, and probably several batches. If kept in an air-tight container, it will keep for a month or more. It's very cheap and pre-made here, but maybe not available pre-made outside Asia. It is quite thick, so has to be diluted prior to application.