(Pictures coming soon)
Chest Guard (Old Way)
The chest guard was made from the same dull leather I used on the body suit , and the shiny leather used on the cod piece. The backing was made from, believe it or not, plastic 3 ring binders. We used the binders as a backing, stitched the straps onto it, and then glued the leather to the binders. It is not as stiff as some other designs using 3mm plastic, but it seems to work well.
There has been a change since we made the chest armor back in the original series. Since then we have changed to using the 3mm plastic as a base, and heating and shaping to the correct form. We cut out the correct shape, formed the plastic, painted the base color, the "gun-metal grey", and covered the "stripes" with a leather-like material, and formed it to the armor. Pictures to follow soon.
Shoulder Guards (Old Way)
The shoulder guards, for now, are made of a black plastic potting bucket cut to size.  The bucket gave it texture with the ridges and valleys made into it, and the natural curve fits right over the arm.  We put industrial velcro on the back of the guards and on the sleeves and just stick them on.
Since we changed the armor, we changed the bells also. Basically following the same method, just this time to the shoulder bells. Pictures to follow soon.
Now, since I am changing my upper armor, these are changing also. I will have pictures of the new armor up soon.
Chest Guard (New Way)
This method, in my humble opinion, yielded greater results. Don't get me wrong. The old armor performed, but was not "perfect". This armor is wonderful. Here is what we did, actually I should say, Here is what my WIFE did.
We have come to LOVE the SINTRA and STYRENE plastic. A plastic used for sign making. You can get this stuff from sign companies, such as Eagle Signs. The Sintra is normally a 3mm to 10mm plastic that has a "foam" core. It is moldable, and shapeable. All you need to use is a hair dryer. The STYRENE is normally a 1 or 2mm plastic that is PERFECT for vacuum forming. Both of these plastics are wonderful for all your costuming needs. I have used it on Vader, R2D2, and plans on a Stargate SG-1 Jaffa and a Fett costume.
Enough about the plastic, on with construction details. We used a piece of Sintra to create a base. We cut it to shape and molded it to the right shape with heat guns. Next we drew out the pattern of the color scheme on the plastic, so we could see what we were trying to accomplish.
The above picture actually shows the armor in mid-construction. But, if you look on the left side, you can see the plastic we used as a base, and the pencil marks for the colored sections.
Next came the colored sections. My wife had this wonderful idea. After watching, oh, every possible angle of Vader, from cut-outs to videos, to pictures, to others who have made costumes, she decided (and I agreed) the colors were black and a deep grey. She had the idea to use a grey vinyl pool float for the grey sections. She had to give it a black color wash to deepen it, but it worked. A color wash is basically paint with water added to thin it down. It will darken the object being covered, but it won't cover it like paint. It is an old model-building trick used on machines to show the seams in the plastic.
She also used leather for the black sections. We found it on the remnant table at our local fabric store. A word to the wise, always check the remnants table. You never know what you are gonna find for cheap.
Now for the tricky part. Vader's armor is not a straight line (as we can see). So to make the curves look right, she found some 2mm foam at Wal-Mart. Stuff is great. She traced the shape of a section onto the foam, and cut it out. Then she would cover the foam piece with the material for the section she was woring on. After she had all the pieces cut and covered, it wasn't much but to glue them down. Below are pics of the process and materials.
One more trick that really helps, soft SCUBA diving weights. They come in 1-6 pound bean bags, and are perfect for weighting down peices while you glue them.
The Finished Product