Im only now coming back to modeling as a hobby. But back in the day, I used to make my own canoies. I used the kit part as master and a small vac-box I hooked to my vacuum cleaner. I got thermoforming plastic and made a small frame from scrap wood.
I heated the whole thing over the stove burner. It worked well, if a lttle crude.
Today I wouldnt mess with it, except in the larger scales.