The untreated wood continued to smolder, so I decided to apply more torch to the treated stuff. Clearly this solution will not make wood and paper fireproof, but it does clearly help make things a lot more fire resistant. For about $30 I got enough borax and boric acid to make about 8 gallons of solution. I think that should be enough to treat several thousand square feet. Boron is quite water soluble, so my understanding is that anything exposed to rain will need to be retreated after a couple of wettings.
