First of all, you have to make your sled boards smooth. It will better for you to use hickory, birch or ash. But, you can use any other type of wood for your toboggan. Just find a wood which is air dried. If you can’t find dry wood, just heat it or kiln dry it and then soak it in the water for around half a day in order to bend it properly. You have to sand all the boards round from the top edges. After that, you have to drill a hole on each piece of board in the centre.
Then, hammer a nail to join the lumber boards to make a curling block of wood. You will have to hammer around five nails to make it. It is very important for you to make sure that all the pieces are parallel to each other.
You have to curl the board through steam for around an hour. You can also boil the three boards to give them curling ends. Then, just slide the ends after steaming to make the block. Put the nail between the sled boards. Bend the sled boards by applying some pressure on them. Now, allow the wood to dry after which it will get into its shape.
Just take the clamping boards off including the block from the sled. Attach them by using a wire and in the end trim the excess wood from the board.
You can use varnish or any other oil to seal your wood toboggan. Besides, you can make it smooth through sanding.