Insulative properties of bark and funnels

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Oliver G

Full Member
Sep 15, 2012
Melbourne, Derbyshire
Good Morning All,

I've been mulling over a particular problem which is how to easily fill a water bag from the billy can without spilling water everywhere.

I have a sea to summit bag tap type affair (Think MSR dromedary) and the orifice is about an inch and a half which combined with a 14cm Zebra billy can I can imagine spilling significant amounts of freshly purified water around. I have previously used a tap or funnel to fill the bag. One thing I want to avoid is carrying additional kit where it can be avoided.

With lightning speed I came up with a possible solution in just under an hour. One could take birch bark, scrub the inside smooth, rinse, and wrap it into a funnel with some cordage. This got me thinking would you be likely to sustain scalds if you held the funnel without a gloved hand, and what natural materials would be best used for a funnel for hot water?


Nov 16, 2019
Vantaa, Finland
While nowhere as good as pine bark birch bark insulates heat fairly well especially if layered as the air gap is a very good insulator. On the other hand water can be boiled in a birch bark cup if carefully done.


Jan 21, 2005
S. Lanarkshire
The bark will insulate your hand, somewhat, but if there are any split lenticles then it'll seep through.

Sometimes the easiest option, since you're already using modern kit anyway and not going the no plastic route, is to buy a simple fold flat silicon funnel.
Like this.

Robson Valley

Full Member
Nov 24, 2014
McBride, BC
Strip the leaves off 6-12" of wooden twig.
Hold the twig against the lip of the billy can, 2" overhang pointed into the opening of the water bag.
The water should follow the twig. Even your knife should work. Experiment in your kitchen sink.
In a laboratory setting, we would use a glass stirring rod for this.