After the small exposed hinge is affixed, I applied heat mainly to the bottom shell to realign the edges. I then held them in the position I wanted and ran them under cool water in a sink to maintain the shape. If I had just let them air dry, they could start going back into their original unrealigned position. If after you have the hinge/pin side affixed there is still a lot of tension on the pin, I'd recommend heating up both sides significantly, placing the pin in and letting them cool with the pin installed. This should decrease the amount of tension that may be on the pin.