I got an old canvas backpack and I'd like to weatherproof it. Some cursory googling yields a number of waxing methods, either beeswax, paraffin or a combination of both. Some recipes also call for adding boiled linseed oil and/or turpentine. Wax is either painted onto the canvas while melted, or rubbed on once hardened. Then you apply heat with a heatgun or blowdrier to set the wax into the canvas.

Anyone have experience doing this themselves? Can you recommend a recipe? Apparently blo can make the fabric susceptible to mildew and adding pine tar can help with this? Turpentine seems optional and is added to help work the wax into the canvas, but can leave it smelling and requires a lot of time outside to evaporate. Also apparently this treatment can make the canvas quite flammable, is that a concern?