I just finished building two toboggans (pix included below). Couple of comments...I used very green white oak (sap still running out a knot!) for the slats (couldn't find ash). I used one 10" and one 12" plastic sewer pipe for the molds. 1 hour of steaming. I never got the amount of bend I would have liked (at least 180 degrees would have been fine and 270 would have been great!) because I didn't properly secure the slats in the molds when I started bending. Also, make sure each slat is parallel to the previous one (and perpendicular to the mold) or the tobog will be "skewed".