First things first, go to the jungle and make friends with a guy who has a big chainsaw...
Pay him 20 bucks to cut down Balsa trees.
Depending on the size of the trees, the general rule is three Balsa logs for a one-person raft, then add one log for every extra person.
Next up, make friends with a guy who has a truck
Find a nice place close to the river for the construction... but not too close — if it pisses down rain and the river comes up, you'll have to start again from step one.
Once you have found a good site for the build, drop the logs in place. Balsa trucks are pretty fucking heavy when they're still wet, so move them by hand as little as possible.
Now that the logs are in place, give truck guy a high five and a few bucks, then peel the bark off the trunks.
These days with rope technology, you can throw the bark away, but the traditional Indigenous rafts used the strong, fibrous bark to tie the logs togther.
With the bark off, strap gopro to chainsaw guy and cut the ends of the logs into points.
This will help the hydrodynamics of the raft and prevent it from spinning around in circles in the current.
Next up: The cross stays....
The cross stays are what keep all your balsa logs together... so this part is pretty important.
First, measure out 2 lengths of strong yet small logs like so:
Then, cut notches into the balsas to keep the stays in place...
Next, carve out some stakes from dried palm wood.
And use the palm stakes to hold down the cross stays like so...
If you do it right, the downward pressure of the upper log will pin the lower log to the balsas :)
And there ya have it: A basic model tradition balsa raft.
Depending on how far you want to travel on your raft, you can add some extras for more comfort and safty. Check out How to Build a Jungle Raft Pt 2 for more fun stuff :)
Please note: This guide is for entertainment purposes only.
There is a lot more to consider when constructing a river balsa. If you seriously want to build a raft for an expedition, send me an email for more detailed information :)