The picture below shows two options for welding the blade doublers to the
hub. Both of these indicate a large amount of weld required to attach the blade
if CJP is required on the blades and the doublers. A sketch indicating this
joint as designed may help. The joints as I have them drawn show a 3/16"
root opening and a 45 Degree included angle. The angle would probably be better
increased to 60 degrees on the 1st one with the 15 degrees on the doubler since
access to the root with the electrode would be restricted. 