I realize I just did a tutorial on adding sleeves to something, but this one was already on my other blog, so I thought it'd be easy enough to paste it over here. I did this project a while ago and didn't take near enough pictures for a proper tutorial, but it's a very simple project, so hopefully this will be enough.
Normally I like to wait to show the final product in a big reveal at the end, but I think the instructions will be a lot more clear if I show you what we're making first. We did a cap sleeve that was ruched where the sleeves met the dress.
We started with a strapless sequined gown that two layers, a lining layer and a layer of sequined fabric. the dress had a sweetheart neckline that didn't go very low on the body. First we picked out some silk and tulle to go with the dress. We didn't end up trying to match the fabrics exactly. We just went into the store and tried out a few different layered color options and picked one that coordinated nicely, rather than matching imperfectly. We only needed about a third yard of each fabric (Our dress was a size 4, you may need a little extra fabric for a larger dress, but I don't think you'd need more than half a yard).
I had my model put her dress on and then we made a rough pattern with some spare fabric. We then cut rectangles the size we needed (thanks to the ruching, you're just cutting a big rectangle, easy, huh?). I believe we wanted our final sleeves to be 6 inches wide, so I cut our fabric 6 1/2 inches for seam allowances.*Since our tulle was sheer, I didn't like the idea of sewing the fabric together with right sides together and basically making a tube. It looked bulky. It looked better to just do a tiny seam, sewing very close to the edges. Serge or zig zag your edges then turn them under 1/4" and stitch as close to the edge as you can. Barely noticeable, see:
Next, I ruched the ends by running a basting stitch along the edges, gathering them and pinned them to the dress. Check the fit before you sew the sleeves down to make sure the sleeves aren't too loose and that the gathering is the same on both sides. I ended up slanting them slightly so they fit over the shoulder, rather than straight over like a tank top. I hand sewed the sleeves to the dress so I didn't have to go through the sequined tulle layer.
You could be done here, but since our dress was sequined and it came with a little baggy of extra sequins, I decided to cover the seam with them and sprinkle them on the sleeve. It made a huuuuuge difference! The pictures don't do it justice. The dress actually looks better with sleeves and I think it looks like the dress was meant to have those sleeves.
Doesn't Sara look AMAZING? So glamorous! That's her standing with her proud parents. My camera died before I could take a picture of her with her date, but he was so dashing in his tux and hand tied bow tie. They looked so old Hollywood. So glad I could help her look amazing and "classy modest", as we put it. :)Our dress had very minimal sleeves in the back, if you wanted more coverage, I would suggest measuring your dress across the back and instead of ruching the back, I would make your straps wider at the back than the front and just sew them straight across the back, while still gathering the front. I don't think it would look as nice, but if would give you more coverage.