The steam from an iron is used to heat and make the cane elastic. Hold the iron 2-3 inches from the rod and apply the steam, rotating the rod for even heating. After steaming for 30-90 seconds grasp in your hands and gently bend in the opposite direction as the set. When the rod section cools it will keep the new shape. Repeat the cycle as needed.
I have also taken the set out of a tip using a toaster, hold the rod section over the opening and rotate for even heating.
Any devise that can apply a controlable even heat over a wide area should work. The steam adds a safety factor since it is harder to get moist steam hot enough to burn the bamboo. An alchol lamp or high power heat gun can easily get too hot. Just go slow and do a little at a time. You can always add more heat, just can't undo if it cooks! Remember it takes time for the heat to penetrate, a butt section takes more time than a tip (not more heat, more time).
My favorite tool for the job is a Sears Craftman (made by Bosche) industrial quality heat gun with a spreader nozzle. It has cont. variable air temp. from 120 F to 1200 F, very controlable.
With a little practice you will get a feel for just how much heat it takes for the cane to get flexible. I like to work with bare hans instead of gloves, if I can't handle the cane it's too hot.
I would suggest practicing on some strips before starting on the actual rod. If you don't have access to Tonkin cane trips you can use the bamboo stakes sold at garden centers. The small diameters (1/8" to 1/4") act much like rod sections and the larger diameters (3/4" or more) can be
split into strips, too small for rod building but good for practice.