This article was originally posted in Instructables and is reposted with permission from Jeremy Dick.
Ever wonder why some canvas, like the stuff a Carhartt jacket is made of, is so much tougher than, say, a dropcloth? The secret is waterproof and fireproof “tin cloth,” invented in some year by some guy — probably an American — who needed something tougher than canvas or denim — tough enough for fighting dragosaurs with a claw hammer on horseback across the Great Plains. Tin cloth is that kind of tough. And you can master homemade waterproofing by making your own tin cloth, using these easy instructions.
To demonstrate the wonders of tin cloth, I took a shower in my clothes and tried to set myself on fire. Allow me to explain.
Step 1: A Simple Recipe
Tin cloth is made by coating canvas in liquified oils that will dry and harden to create a fireproof and waterproof fabric. My recipe calls for beeswax and boiled linseed oil. To demonstrate how to waterproof fabric, I coated my Instructables apron. The reason I made gallons of the tin cloth mixture is that I also needed to coat a 20-by-24-inch canvas tent that I sewed for winter camping. Coating the apron only used about a cup and a half of the liquid.
Beeswax (I used toilet gasket rings: dirt cheap)
Boiled linseed oil
(Optionally, you can add turpentine. I saw it referenced in a few places in my research, but opted against using it because it seemed to increase drying time.)
Melt and mix together the beeswax and linseed oil. The tin cloth mixture doesn't have to reach a certain temperature; it just needs to get hot enough to ensure complete combination of the ingredients.
Step 2: Application
Paint the liquified mixture on your canvas apron, tent, or whatever you want to waterproof. You'll know when you've applied enought because it will be really easy to see when the canvas is properly saturated. I had to coat both sides of the apron's pocket areas to achieve penetration.
Make sure the solution is brushed on evenly, give it a quick inspection and then hang up the canvas to dry. The drying should take two days-ish, depending on conditions.
So, how did my homemade waterproofing fare when I put the apron through its paces?
Step 3: Let's Take a Shower, Robot!
As you can see in the photo below, water beaded up immediately on the tin cloth apron. The water stayed beaded until it evaporated: zero penetration.
As far as the flame resistance goes, I figured that if I held the lit blowtorch to the tin cloth while I was wearing it, and kept it there until I couldn't stand it, that would pretty much simulate the worst possible kitchen flame. I did that about 10 times until it raised my pink. I'm not always the smartest guy in the room, especially when I'm alone (which I frequently am).
The blowtorch made no marks on the tin cloth and even left the Instructables Robot unscathed! This exceeded my expectations.
But the real test was chocolate. I quickly scoochmarooed a mug cake with pecans and semisweet chocolate and dumped some on the tin cloth apron. I let it sit long enough to take some photos and eat my cake. Then I just wiped it away. The apron looked like the cake was never there. Indestructible!
You can see more photographs of this project on my original Instructables post.