Hi, I have a large seam that I need to glue together on a helmet that also needs large gaps filled. Can someone suggest the best method to guide me in the right direction? The seam goes all around the helmet and the two pieces only make contact at a few places. The rest of the seam has gaps ranging from paper thin to as much as 3mm (1/8th). I was thinking I could glue the contact areas with super glue to hold it in place, then fill the gaps with some rigid material. I want to avoid hot glue or epoxy glue because I find that it has a bit of a soft feel to it when dry and I'm worried that the slight amount of flex would crack the bondo that i plan to lay over it. I was also considering pouring smooth cast into the cracks but I can't figure out how to have it pour evenly into a curve without leveling off when drying.
Here is an image of the seam at one of the bigger gaps:
I'm open to new materials and techniques, as long as it makes a rock hard super bond like if the two halves were always meant to be together.