Repairs

[Nick Dennis]

The birchbark which we have found the U.K. needs some repairs. Especially the gores have opened and need to be redone with the caulk mixture. What is the best recipe with ratio of far, sap charcoal etc. obviously bear fat is hard to get in the Thames valley. Thanks in anticipation. Nick

 

[Rob Stevens]

The thing about superlatives is, they are the most.
Spruce resin/pitch.gum + fatty substance. Just about anything will do, though there are those who will tell you that one oil is "better" than another whether it be Crisco (all vegetable shortening), bacon fat, peanut/sunflower/rapeseed/canola oil, etc.
The ratio is approximately one or two large table spoons per skillet full of resin/gum. The consistency of the mix is determined by the weather conditions. More fat if paddling in colder, wetter, less sunny conditions. Less if warmer climes. Some people add epouse adding ground charcoal. Not sure what advantage this affords.
See Cesar's bark canoe. Start at 46:20, but especially 48:15+ for application.

César's Bark Canoe

This documentary shows how a canoe is built the old way. César Newashish, a 67-year-old Atikamekw of the Manawan Reserve north of Montreal, uses only birchbark, cedar splints, …

www.nfb.ca