In which the crafter learns that science is only half the trouble...
After I performed some experiments with wax, I felt ready to start my waterproofing! I sewed the sturdy backpack pieces together, until there were only two sides to be sewn, I didn't want to wax each piece and then deal with sewing all the waxed seams.
So, using my little blocks of prepped wax, I began rubbing. And rubbing... and rubbing... and I finally completed one section. It wasn't sinking into the grain quite as much as I wanted, so I figured I would warm it up a little. I held it over a candle, which works swimmingly, but took a while. I realized I couldn't use this technique as some parts of the bag had multiple layers of fabric to warm thru.
If I make any more waxed items I think I will invest in a thrift store hair dryer, faster than the candle, more versatile than the iron.
I riveted on leather straps for closures, and a belt that serves as shoulder strap. Not pictured - me hammering nails through the belt to get holes... it is very thick leather!