And this is where the fun begins. The hand sander is officially my Best Friend.
It doesn't look like much right now, but when I was at this stage about two weeks ago, I was just starting to get used to using the hand sander. The black areas you see had begun to smoothe out, but the important thing is to always tilt the helmet away from you and to see it at an ant's eye level to see how much more sanding you have to do.
Again, I don't recommend PC-7, but in this picture...
... I attempted to use putty to fill in those areas I just discussed. It has since been all removed (forcably) and replaced with QuikSteel which has been wonderful and shapable with 80 grit sandpaper.
Again, it's important to establish the necessary areas before doing this, else you're filling in and smoothing out your finish and yet there are still bumps and distortions that prevent the mid "rib" from gaining definition.
In this particular case, the change from the dome surface to the rib was very abrupt, and so putty is needed to fill up the cracks and to round things off.
And here's a first examination of my efforts. I have found that gray primer is a very nice neutral color to allow you to see shapes well. At first I thought black primer (even black fiberglass) is cool, but black has a tendency to hide details and inhibit proper visualization. Gray is better. Sure, it's fun playing with a project that's black because Vader is a black-themed costume, but the worst thing that can happen is for you to find distortions and stuff after you painted it. Then you'd have to remove all that paint and sand it all down to re-establish the last known good surface!
Now it may seem like I did the entire dome but I didn't. I only did the front. The top is the least likely-to-be-seen area, and it's somewhere up here (an inch or two away from the injection molding hole) that I chose to begin transitioning from sharp to shallow. This is going to be tricky. As it turns out, the rib on the back of the dome is quite pronounced, and I don't see any reason to mess with it.
From this point on, I continued sanding down either side of the mid rib, as well as the mid rib's own two sides and surface. The rim's "eyebrows" or "frown" have begun to look better and better. I've worked extensively to not only eradicate those grind lines I carved in, but to smoothe out the transition so that the line where the neck protector joins with the skull cap is of similar "blurr".
More photos to come! Stay tuned!!