I’ve been getting a lot of questions about how to waterproof your ruck. So in this post I’ve included a few ways to do so without harming your leather or canvas.
You can use a turpentine-wax or oil solution. Simply rub in the oil into the canvas and cover the entire bag.
You can also use a laundry detergent and alum method where you soak the ruck in a detergent-water solution then let dry and steep it in an alum-water solution then let dry.
The easiest way of waterproofing the canvas is to buy seam sealer and a fabric waterproofing spray. You can use most on both leather and fabric so there's no damage to your leather strapping.
Personally, I don't waterproof my ruck with a solution. I use a waterproof cover. It’s quick and easy to use and in really wet environments (like wading through a river in the Congo) I use a waterproof bag. I slip my ruck into the waterproofing bag before the move ensuring my ruck and contents stay 100% dry. The extra volume of a cover and waterproofing bag are very much worth the extra few ounces in such environments. My reasoning behind not sealing the canvas with a solution is that I like to maintain air flow through my ruck. Having a cover that I can easily remove allows me to air out my wet clothes from the inside of the pack. My change of clothes stays nice and dry inside my waterproofing bag so I don’t mix dry and wet items together.
In the end it's up to you. If you do decide to use a water based solution remember to treat your leather first to prevent unnecessary damage.