And now for something completely different....
The corrugated dryer ducts are NOT your friend. They are inexpensive, yet they trap the dryer lint. Thus a great source of fires in the home. Use galvanized metal. Smooth surface, and the screws you use to connect pieces together must not penetrate the duct, else link will build up around the screws.....just food for thought.
Great safety reminder Redshaw, and and like electrical cords, periodic inspection can help maintain and prevent accidents and catastrophes.