A way around the canvas shortage is to buy those surplus cylindrical kit sacks used by soldiers to carry their gear. You can often find them unused and in excellent condition. The only problem is the color, they only come in various shades of olive drab. But they are made of 100 per cent heavy cotton canvas and one of them has enough cloth to cover a case.
For waterproofing I use self made wax made of beeswax, linseed oil and turpentine (pine turps not white spirit). Apply, use hair dryer to soak in and repeat till the cotton has absorbed enough.
