You can use almost any soft wood such as bass, pine and probably poplar and a few other open pore woods. I doubt that a hard wood a walnut or maple or cherry would work very well BUT, any of it is worth a try!
The idea here is to boil the wood in water to force out the air in all the pores and replace it with water. then you can squeeze (or stretch) the wood which squeezes out the water and allows the wood to hold the shape it is squeezed into for a short time. Then you re-boil it again (to refill the pores with water and take back it's original shape) and let it air dry in the "relaxed" original shape and you are done. It is a lot like steam bending that is used in building furniture.
It is fun to try a few times. I made several of these "Nail in a Tubafur" things just for fun and had two or three crack but, was successful with eight or ten of them and they are real conversation starters.
Rog
PS If I remember right, I had to boil this white pine 2 x 4 about 15 or 20 minutes to get all the air out. But, I was squeezing one leg down in a vice to about 1/2 it's normal width so I could drill the hole and install the nail. Then re-boiled it another 15 minutes and watched it go back into more or less original shape and then after letting it air dry for a day or so you could not tell that I'd ever done anything to it at all.
Rog
