Here's a little update on visor installation. In my opinion it's best to have the visor area cut out and sanded properly before you start this. You might try before that's done but then your visor won't fit as well. You can buy pre made visors from a number of vendors but there wasn't a boba fett visor shop in 1978 so I won't be using one. My way is more fun too. When I first started looking at this I was thinking that those guys in 1978 were crazy and that from a design point of view the chicago screw method was better. Actually I've changed my mind and think this is probably one of the better methods to attach a visor. One of the great advantages is that the visor is a proper rigid fit rather than constantly fighting the wish of flexible visors to return to flat.
The first thing you'll need to do is buy some A4 sheets of dark grey smoked perspex. It'll likely come in packs of 5 or 10 but don't worry about that as you may not get it right first time and perspex is brittle and prone to snapping so your spares will come in handy (I went through 7 sheets before I was happy).
Then you'll need to take some measurements from your helmet to come up with a general visor shape and from that you'll make a template. Here's my template which should work for most helmets but will probably work best for those in the MR size and shape range.
This is an scan of a drawing of the outside of the template I cut out using my measurements. If you're thinking it looks a bit untidy and uneven then you're right but as the helmet is not symetrical and as you'll be trimming. sanding and tweaking after the initial cutting that really doesn't matter. The bottom section is deliberately left overlong and it shall remain so on the visor until the visor fitting is complete when it will then be trimmed to match the fit of the visor to the helmet.
Once you've done the cutting you'll end up with something like this:
This was actually an early one I didn't end up using. I hand cut mine which was more difficult but I suspect it was how it was done back then. The visor that is taped inside the PP2 is pretty untidy in a handcut kind of way. I could be wrong of course.
Avoid the temptation to remove the protective film if you can because if you remove it you run the risk of marking it when fitting it.
Now, this next method is really only going to be available to those of you working with fibreglass helmets. Those with resin lids that warp under heat won't be able to do this.
Use a heat gun (mine's a black and decker) to warm your visor so it becomes mildly flexible and then lay it on the OUTSIDE of your helmet and then apply a bit more heat unitl it starts to match the shape of the curve of the outside of the helmet. Let it cool slowly for a bit until it becomes slightly less flexible and then place it INSIDE your helmet and heat some more to match the inside curve. Once it's more or less where it needs to be place it in cold water to cool it quickly and set to shape. The story won't end here and there'll be lots of trimming and minor reheats to get a better fit but that's the essence of it.
Once you've got that good fit the visor will actully sit in place with minimal pressure. Tape your visor into place using gaffer tape. For the next phase you'll need some visor clips. It will be easier to do the bottom set first so start there. I used milliput to fix mine into place (i'll paint it a better colour match later). Enusre the screws are in place in the tabs but after you've fitted the tabs make sure there is no pressure on the screws (because that will push the tabs out of place). Once you've got a decent placement you'll need to LEAVE IT ALONE FOR 24 HOURS so it can cure properly. This is roughly where you'll end up (you can't tell from this picture but the visor is long at the bottom because it hasn't yet been trimmed).
Live the dream
Update: I'm no good with anything metal or technical so following some discussion with kurtyboy
I turned to Sidewinder for these. There was an initial consultation in which I provided SAS with not very much material and he provided me a prototype set. Based on those I then sent SAS a drawing with some revisions and he made me a revised set. On arrival I could see they would be the ones. I made some minor tweaks to them before installation. If you want a set of clips Sidewinder
is your man.