Went ahead and printed this fantastic model as practice for future costume parts. Hindsight is 20/20 and I learned a lot but overall it came out better than hoped. I printed at 102% and while I still had to cut the back off and make a "hatch" I think I would have been fine at exactly 100%. I think overall the model is a bit big, but I'm not sure you could get it smaller without it being custom made for your head proportions. The whole thing is made from HIPS only because I use it as support, but not often enough, so I had plenty to spare.
(Re-ordered the images to show finished first. Build process starts at Pic 15 and then loops back)
Pics 1-9: I did a lot of weathering. There are some videos on youtube I watched, some even for other red hood helmets. I used a large square file and scraped in some spots, cuts, grooves, dark black washes, dry brushed some silver here and there. I also hot glued in some tinted safety glasses lenses. One seam flaked off a lot of bondo so I used it as a really deep cut and it looks pretty good.
Pics 10-12: Keeping true to my original intent for this to be a test bed project, I wanted to try some bullet strikes. They look really cool, if not really accurate. I took a blow torch to a domed lag bolt, and smashed it into the helmet in a few places. Doing direct hits is easy; graze marks are harder. I like how it peeled the paint up around the edges, although again, maybe not accurate. I went over those spots with more dry brushing and washing, and took that opportunity to add some orange rust spots, mostly near the bullet strikes.
Pics 13-14: Finally added the internal padding. I hinged the back "hatch" with a piece of elastic, and put some rare earth magnets stolen from some building toys, down near the ears. The padding is mostly eva foam around the top, to get the height just right, and I used a lot of weather stripping to finish out the edges. It actually fits like a glove now. I may add electronics in the future, but for now, this experiment is a success.
Pic 15: Printed all 14 parts separately. Could have printed about half that many on my printer, but I was lazy. I HIGHLY recommend at least fusing the two chin pieces and the eyes across the nose bridge if your printer can. Otherwise, maybe cutting up the solid model yourself. I had lots of problems with the chin breaking along the seam in the finishing process, and the nose bridge is hard to sand.
Pics 16-20: Initial assembly and sanding. I super glued the parts together. I didn't like how the top went together, but I decided it was too much work to break them apart and try again. I should have tried again, as those seams proved to be hard to cover. I would also suggest immediately coating the inside at least, with liquid epoxey, to reinforce all the joints. Will save you a lot of trouble later. Sanded from 60-220 grit. Doodled some ideas that were scrapped.
Pics 21-23: I tried Bondo for the firs time, based on one of the other builds here. It is easy enough to use and sand, although I occasionally used a belt sander to heft off large bits. In the future I will use epoxy on the inside and Spackle to fill the outside, because while Bondo is easier than epoxy to sand, spackle is way easier than both haha
Pic 24: After sanding the first bondo layer smooth, I thought I might be done enough to paint, so I put on a layer of primer and lo all my seams and mistakes were revealed
Pics 25-27: I decided to try more bondo. This could have been a mistake, but it ended up working out after several hours of painting. I also ignored the instructions to sand off primer, and that definitely was a mistake. because while my primer was rated for plastic, and dried over 24 hours, the bondo stuck to it better than it stuck to plastic. Lots and lots of sanding later...
Pics 28-31: I primed it again, and it looked better, but I was dumb and did it in the dark and dropped the helmet on the pole I was using to paint, and cracked all the seams in the top, and some in the front in back... So More epoxy, which again, should have been coated from the beginning, And more sanding.. At this point my seams were nearly invisible though.
Pics 32-35: The scary part. I was actually so annoyed at myself with this that at this point I almost skipped making the helmet wearable at all. I'm glad I didn't though. I used this handy ruler tape I have and a compass to draw some arcs on either side of the helmet and have them cross at a horizontal line in the back, and then basically free hand cut it with a dremel. It worked out fantastically. Probably should have sanded the edges more smooth, but whatever. Probably should have filled the now exposed print layers, but...whatever
Pics 36-39: As I had actually intended from the beginning, I primed the helmet again, and painted the whole outside with a truck bed-liner to give it a rugged finish. This worked fantastically, and also helped to hide any irregularities in the bondo finish. After another day, I painted it red with a flat(or so it said) metallic red car lacquer. Again, I got really lucky, because the color came out exactly how I wanted. Not glossy, but not plain red either. Then I masked off the lines and did a garbage job of painting the black lines.