I guess Instructablers are really green generally so you will like this way to recycle the dead umbrellas and at the same time have handy compact shopping bags so that you never need a plastic supermarket bag ever again. They roll up so small you can keep one in the pocket of each coat and handbag.
Step 1: What you will need
These are very easily come by, especially in city centres in wet windy weather. In one week I gathered over 30 umbrellas on the 2 minute walk from my home to the station and the 10 minute walk from the station to my office in the city centre. I just helped myself to the umbrellas jammed into the public waste bins.
Here in Glasgow the small, telescopic umbrellas are popular and the majority of that type are black. I ended up with loads of them and, to avoid making a million small black boring bags, I used a lot of them either for lining some bags or for making handle strips. If you dont do that then you will need something to make handles or straps from: tape, bootlaces, string even.
Step 2: Preparation
Skin: the fabric of the umbrella
Struts: the metal or plastic rods that make the umbrella's skeletal shape under the fabric.
Ends: the little plastic thingies which are sewn onto the fabric and fit over the ends of the struts.
Handle: the whole thing from the bit that you hold, right to the ferrule.
Ferrule: the little end piece (metal or plastic)that makes the pointy bit on top of the open umbrella.
When you find the dead umbrella it is almost certainly going to be sopping wet ('cos its raining, innit?) and possibly grubby too, so you have two choices:
carry it home in a bag you carry with you for that purpose,
Strip the fabric off right there and then. You can really only do this with some of the big "golf" umbrellas. Due to the way they are made, you can slip the stitching over the struts and pull it straight off over the ferrule.
You cannot do that with the telescopic ones though, because the stitching is more complicated. I always have a penknife in my handbag (as in NCIS Gibbs' Rule 9, but i have always done this as you never know what you may find in your travels)and am shameless about stripping the skin off an umbrella in public.
Most umbrellas' end bits just pull off the struts, and are still sewn onto the fabric edge. If not you will have to cut them off with scissors. Then you have to cut the thread that sews the struts to the fabric - usually 3 or 4 points per strut. Lastly you have to cut around the ferrule to get the whole skin off the struts.
Now wash the fabric. It will dry very quickly. If you want to iron it smooth, be sure to use a cotton teacloth or something similar between the umbrella fabric and the iron or the fabric WILL melt excitingly.
Step 3: Cutting and sewing
Umbrellas are either 8 skin panels (octagonalwhen you lay them flat)- picture 1, or6 skin panels (hexagonal) - picture 2. This affects what you can do with them.
The basic shopper is made by cutting the skin in half - pictures 3&4. Then you fold one half in half again, with the right side inside - picture 5.
From an 8-panel skin this gives you a shape which has the former edges of two panels at the top of the bag and a steep point for the bottom of the bag. Sew up the side and put some handles on and thats you done.
I do all my sewing with an old hand sewing machine I got out of a skip (dumpster in USA) so the bags are totally carbon neutral.
If truly desperate you could probably assemble these with staples and duct tape.
Step 4: Bags galore