When laminating and steam bending wood you do need to be aware of the grain of the wood. Avoiding areas of short grain and twisted or wild grain helps ensure that the result is closer to a true curve.
In terms of laminating the spring back is dependent on the number of laminations.
This is the equation.
Percent of spring back = 100 x [1÷(N²-1)]
where N = the number of laminations.
This equation can be found on:
http://davewoodshop.homestead.com/coldbending.html
and on other internet sites.
This can also be expressed as :
r = R÷(N²-1)
where:
R is the radius of the former
R+r is the radius of your finished work
N is the number of laminations
Steam bending is more forgiving as you can over bend the wood and then relax the bend a bit if it is too tight by opening it out a little.
There is a short period of time when the cooling timber is still a little 'adjustable' when it comes out of the mould. When it has cooled properly it will be pretty much fixed.
You can re steam it but you will need to make a curved steam pipe to take it.
I've already planed down the thin strips of well seasoned english ash.
