copper vs galvalume

I have a cedar roof coming up, that calls for a few metal dormers. The dormers have a concave and conves swoop to them. Originally we had planned to form our own panels and hammer a double lock seam out of copper. I have no problem doing this. Now to save money they want to switch to a 24 ga. galvalume. I have never formed a panel like this out of anything but copper, what will i be getting myself into? I forsee problems with the swoop forming nicely in the double lock with a harder metal? Im a little nervous about telling them this can be done. Any insight or past experiance would be great.

Thank you

good point coppersmith, i was so wrapped up in if it would even be possible to make this work i did not even consider that. i went back to them and told them i would only be willing to do copper , untill i can make a mock up in the shop and try it with the galvanized. thanks for the reply

I can see doing it but once you run the galvalumne through the shrinker or stretcher you will ruin the coating and it will rust. Copper is the best choice for what you want to do.

i wish they would eliminate the curves but im not sure that is gonna be a option, i think it comes down to copper or nothing, thanks for the reply.

Lots of luck bending that. I think they can oder specially bent panels, but it might cost more than copper. 28Ga. galvalumne can be bent some, but it'll still split. Just tell them to eliminate the curves and you'll be good to go.