From what I've read, paraffin is the chief ingredient. There are also references to beeswax and linseed oil, so I've played around with all three with a ratio of four parts beeswax/paraffin and one part linseed oil. So far it seems like its a basically functional recipe, but there is still something happening in the commercial products that I don't understand. There is somehow more of an oiled, less waxy quality to professionally manufactured material. (An aside: Did you know early on sailors treated their sails with linseed oil, which turned them yellow? They then started using the sail material for rain gear, hence the ubiquitousness of yellow rain jackets.)
A shop apron I made recently
With my concoction I heat it up to liquid form and then paint the wax onto the untreated canvas. It goes on pretty easily but then hardens up unevenly and quickly, so I then put the whole thing in the oven at about 200 and that makes it saturate and even-out through the material. It's ready to go after that.
This is well and good, and offers a modicum of repellency to the fabric, but it's not quite the highly water resistant result I'm hoping for. I've wondered if perhaps petroleum jelly might be worth adding to the mix; it's sticky yet pliable and quite hard to remove.
A pair of canvas Converse sneakers, waxed
The nice thing about being able to wax material myself is that I'm not limited in what I can make bags out of; I love the look feel and texture of waxed cotton and enjoy the potential of being able to wax whatever I like.
An appealing aspect of this experiment is that we collect wax from our beehives and have accumulated a reasonable supply over the years. It feel good to have this a somewhat locally produced product. Makes me wonder where linseeds grow, and are linseeds from a tree? a shrub?
The waxed parts for a handlebar bag in process
I recently made myself a handlebar bag from home-waxed canvas and it worked pretty well in the few rain and snow showers that its been through. It's not waterproof, but I get the impression that it is resistant; that water stays at the outer surface, even if the moisture is not exactly beading on the outside.
Applying the melted wax
This is an ongoing experiment and I'm encouraged with what I've come up with so far. If anyone has experimented with their own waxing process or has any insights or suggestions, I'm curious to hear what you know.
I got ahold of some petroleum jelly and rubbed it into a piece of canvas. It seems so like the commercial stuff--quite repellant and saturated without being really waxy at all, but also not too oily. It'll definitely be what I'll try with whatever the next project is.