I finally finished the reversible shell. It really did not take that long to make, I just worked on it a few minutes a day for a few days.
The view you see here is a mystery fabric that I found on a remnant table at Britex in San Francisco. It is a kind of mesh like knit, very stretchy, and very sheer, with a sheer black net-like backing. It is probably nylon. It melts very easily but I did not do a burn test on it, just accidentally hit a corner of the backing with the iron.
Here is a picture of the fabric held up against the window:
You can see how sheer it is, much too sheer to wear by itself without layering, lining or significant draping (or all three). I found a lilac rayon/Lycra knit that coordinates with the lilac color in the print very nicely. The rayon is also quite light, almost a lingerie weight, lighter than I would normally use by itself, but perfect for combining with the printed mesh to make a two-layer reversible top.
From here on down, those of you who sew far better than I can ignore this post as I am going to go into all the boring detail about this simple top. Part of my reason for making this blog is for myself, to keep a record of what I do and why because I am inclined to forget and then run around like crazy trying to remember where I put the instructions for something, or how I did something and so forth. A blog is actually easier than filing pieces of paper, which I invariably lose.
The following pictures will all enlarge if you click on them.
Here is a picture of the pattern pieces cut out. I cut one complete top out of each fabric. No facings or other pieces are required.
The pattern is an OOP Butterick pattern, 3124. It contains instructions for making the top that are quite clear. I forget that they are there as I have applied this technique to so many things. I think I originally got the instructions from Sandra Betzina's e-mail newsletter and they are available on her website for those that subscribe.
Of course the first step on any top is to reinforce the neckline, I used a fusible twill tape. Then I sewed the darts on the two fronts. After that you combine the two fabrics to make a two-layer front and a two-layer back. This is done by sewing the fronts together at the neck and armhole seams and then doing the same for the back. Sew the pieces right sides together, (you can see them pinned for sewing here) LEAVE THE SHOULDER SEAMS OPEN!! It is important, when pinning the front pieces together at the armhole, to make sure that the darts are lined up on both pieces. If one dart is lower than the other (from the armhole) the shirt will not hang and drape correctly. This seems obvious, but it is easy to forget in thrill of construction.
Here are the two pieces, sewn, trimmed, and 
turned. The pattern instructions tell you to trim and press the front of the top but not the back. I have found that, for me at least, it is better to trim and turn both pieces and press them very flat while they are separate. It is then pretty easy to open the back back out, wrong side out and press the seam allowance flat again for the next step. By putting in these few minutes of extra pressing you get a much better looking end result and I have fewer problems putting the pieces together.
The next step is to put the two pieces together and sew the shoulder seams. You do this by leaving the front right side out and sliding it up inside the back, which has been turned so that the wrong sides are facing outward (toward you). This way the two right sides are facing each other when you sew:
Once the shoulders are sewn, trimmed, and pressed the top can be tried on for any final tweaking of the fit and the side seams can be sewn as one continual piece on each side:
Then all that is necessary is to press the seams and hem the layers, leaving each side hanging free.
