Hi Dave,
Sikaflex is very strong stuff indeed, but it has a curing time ( dependant on temp of the area), so it may not "hold" the ali in place during the curing period, maybe set it in place but use those cheap straps that you can get from motor factors etc to hold it all together whilst the sikaflex goes off, after it has then i,d think it,ll be a strong enough bond.
cheers
andy
ps.... don,t get the stuff on your hands ......takes ages to get off
