Basic, shopping bags are great for toting around all your cool stuff. Even better they are simple to make. Use French seams on three sides of the square. Add some handles and hem to the top and you are done. Because of the French seams there is no need for a lining. Thus they use less fabric, fewer resources, and are less expe nsive to make.
But sometimes you want a bag with a little more substance. Once with a boxed bottom but still with the ease and cost effectiveness of a bag without a lining. This Instructable shows you how to box the corners on your basic bag to give it that substance and style.
Instructions for cutting and links to basic directions can be found here.
Step 1: Nesting the Seams
Once you have sewn the French Seams all the way around your bag you are ready to box the corners.
In the picture, the bag is inside out. I am holding the corner on the RIGHT side of the fabric. I have lined up the stitching and have made sure the seam allowances go in opposite directions. This is called nesting the seams. If you tried to put both seam allowances in the same direction it would be too bulky to sew.
Step 2: Marking the Corner
Turn the bag RIGHT side out. Carefully keeping the seams nested. Lay the corner on the table like you see in the pictures. Remember to keep the seams nested. You can feel through the fabric to see if they are. The seam allowances will feel like one smooth section with no gaps or ridges.
Line your ruler up on the the sewing line. You can see that in the first two pictures. The point of the bag should be at the depth you want your seam to be at. I am sure there is some magic rule relating the depth of the seam you make to the width of the box. Whatever. I usually stick to a seam depth of 1 - 2 inches. In this case it is at 1.5 inches. You do want to remember how deep you make the seam on the first corner so you can match it on the second.
Carefully draw a line across the corner, perpendicular to the seam. I tend to use markers or pencils that can wash out. It isn't critical because the mark will end up in the seam and won't show. But you are drawing on the outside of your bag at this point and you want to be sure you have your line even and in the right spot before you pull out your sharpie.
Step 3: Pin and Sew Th First Seam
Use a couple pins to keep everything in place.
Sew directly on the line you drew. Go from edge to edge. Backstitch if you like.
Step 4: Cut
Yep. Now you cut away the corner. Leave a scant 1/4 inch seam allowance. (Or a scant 1/2 inch seam allowance if that is what you use.)
Step 5: Seam #2
Turn your bag inside out.
Carefully poke the corners out and lay the corner out so that the seams are nested (this time you can see the top seam.) Feel along the seam to make sure it is smooth with no ridges or gaps.
Sew a full 1/4 inch seam (or half inch if that is what you are doing).
Backstitch on each end.
Step 6: Finish
Turn your bag right side round. Trim off any little threads that might have escaped your seam. Repeat on the other corner.