I did not solder anything, but it would be a lot simpler to do so if you have the skill and resources. Also, most things are taped down because I bought a hot glue gun halfway through the project. I definitely recommend the hot glue.
When I took the pictures in the gallery, the room was pretty cold so the Arc Reactor was blue. However, I blew hot air towards Iron Man's temperature sensor to simulate a warm environment for one of the pictures, so you can see both the pink and the purple Arc Reactor as it cooled down.