The references that I used for the vest are the photos of Luke from A New Hope in Costuming in a Galaxy, Far, Far away, the official costume book to the old trilogy of Star Wars films. Beware that in ESB the flak vests were worn backwards, and the X-wing costume has been presented like that in many exhibitions as well.
Then it was the X-wing pilot standards in the Rebel Legion forum. If you are aiming for Rebel Legion approval you need to read up on the standards and know what is required.
In the X-wing pilot forum there is also a tutorial with measurements for a flak vest, and I'm pretty sure but not certain that those measurements were taken from a screen used vest.
- In the original some kind of nylon was used. It's a thin fabric and when looking on references the fabric is a bit translucent. I couldn't find a nylon so I used what remained of a plastic coated thin fabric that I used for the flak vest for my A-wing pilot. Nylon is probably easier to work with.
- The side buckles and adjustment buckle were ordered from WampaWear. The tutorial I linked to above have links to where you can buy them, or what search words to use if you want to look for them online.
- A small scrap of white leather, I used a fake leather that remains from when I did my Princess Leia belt.
- A roll of plastic tubing. I chose a clear plastic tubing with an inner diameter of 3 mm and an outer diameter of 5 mm.
- White cotton grosgrain tape
I started off creating a pattern from the RL tutorial above on a piece of cheap cotton. When I had a pattern piece that I thought looked good I tried it on my dress form.
At this point it looked like I would have to have some kind of dart in the front to fit my bust. I also got a bit of panic when I started working on making the channels in the fabic that would create the ribs. The RL standards call for 16 ribs, and I could get 8 maybe 9 on to the backside. I had started with planning to use 5 mm tubing, but that would mean fewer channels. I switched to the smaller tubing and sewed the back. The backside is constructed from two pieces of fabric, with the tubing sandwiched inbetween.
This was the resulting back of the vest. I was not happy with it though. The ribs should be as large as the empty space between them, and I felt that the empty channels were too wide. I also thought that the curve on one of the sides simply didn't look good. After a whle fiddling with trying to even the sides I realized that I kept thinking "this will do for now, but on my next vest I'm going to do like this instead". It was clear that I wouldn't be satisfied with the vest so I started over. I made a new pattern and cut out new pieces for the back and front.
This time I started with finishing the bottom layer, with a simple turned hem, and then putting a smaller piece on top of it. The smaller piece, that will help create the channels is smaller on the sides, but reaches the top and bottom of the other piece. I sewed the two layers together just a few mm from the top edge, so that they wouldn't shift. As you can see the fabric is very creased, and of course since it's plastic I can't iron it. The good thing is that it doesn't ravel so I don't have to worry about finishing the edges.
The straps for the vest were made by first cutting a piece of cotton, and then folding a piece of the plastic fabric around it. Then I sewed line after line after line to give it a flat ribbed appearance. I had hoped that the cotton backing would pad the strap a bit and make the quilting more prominent, but in the end it made no difference.
The straps were pinned to the back of the two pieces before I started to sew the channels.
The plastic did warp while sewing. As you can see I'm using my roller foot, I tried at first with a regular foot and the fabric wouldn't move under it.
The trick in making the channels and rib look like they are the same size when the tubing is inserted is that they are not the same size. I made the channels that were going to be ribs 1 cm wide, while the channels that were going to be empty were 0,5-0,75 cm wide. I switched the width by changing the needle position on the machine between each row. The distance between the middle and the outer position is 0,5 cm.
Another thing that will happen when you insert the tubing is that the whole piece will shrink. Not a lot but enough that it affects the total length of the piece. Make it a bit longer from top to bottom than the finished length that you are planning on. It's easier to adjust by cutting off the excess from the bottom, than having to figure out how to get it long enough when all the ribs are finished.
To finish the backpiece I made a short sleeve of fabric and sewed it on over the channel that would have had the 2nd rib from the botton. I then inserted the cotton tape through it and fastened it with the adjustment buckle.
For the front I started wtih a new pattern as well, and instead of the dart I could fix the gaping issues by working with the curve of the side and placement of the side strap.
Otherwise the front was made in the same way as the back, except of course the section without any ribs. There I just sewed 0,5 cm channels, but they aren't filled with anything. The side buckle is attached to a small piece of leather that is then attached to the side of the flak vest. It connects with the strap from the back. Here it simply took a lot of trial and error, while wearing the fight suit, to get it to fit just right. In order for the strap to stay put I have sewed it closed, and sewed it to the back piece. That means that I can't adjust it, but it's not a hard thing to replace if it wouldn't fit any longer.
A final thing about the flak vest. In the Rebel Legion standards it's made clear that the flak vest needs to be proportional to the wearer. The most common reason for denying a pilot costume is that the flak vest is too long, reaching almost all the way to the waist, or to the belt. A danger with ordering a flak vest from the common vendors is that they usually only ask for circumference of the torso, not length which might give you a flak vest that is too long. If you look closely on my vest you will see that it does not conform to the Rebel Legion standards of how many ribs each piece should have. I have chosen to shrink my vest a bit, since I'm 10 cm shorter than Mark Hamill and the standards are made from the photos of him wearing a vest. That's also a reason why I went with the 3 mm tubing instead of the 5 mm. On the front my bust made my measurements almost the same, since that increased the length of fabric needed to cover it, but in the back I have fewer ribs than called for. I think this does look more proportional, and a lot better, but I don't know how the legion costume judges will judge the flak vest and the fact that it's lacking the correct number of ribs.
edit/ this flak vest has been approved, and I didn't need to change anything