Step 1: Gather Materials
1. Vinyl banner (truck tarp)
2. Soft material for padding (I used a blanket)
3. Lining material (I used corduroy)
4. Sewing machine
Step 2: Cut up the Blanket
I used four layers of blanket material and one layer of corduroy and diamond quilted it to ensure that there would be enough padding.
Cut the blanket into four equal sized rectangles that are big enough to wrap around your laptop with a few inches to spare. Cut the corduroy to the same size but with one side double long. This will be the inside lining of the flap. Stitch two seams down the middle where the spine of your laptop will go.
Step 3: Quilt the Padding!
Use a ruler and chalk to make lines that criss-cross on your padded section about 3 or 4 inches apart and that intersect to form diamonds. Do this on both sides of the padded part of your laptop sleeve.
Then, sew along the lines that you drew being careful not to let the fabric bunch up.
When you have quilted both sides, fold the whole thing in half and put your laptop in it to see how it fits. Mark where the sides should be and sew up the sides, (through all 10 layers of fabric) making sure to backstitch when you start and finish. (This was the hardest part for my sewing machine to handle--it broke several heavy-duty needles !)
Cut the excess off the sides, leaving about a 1/4 inch.
Step 4: The Outer Part
Start by placing the padded part of your bag on the banner and measure (by wrapping the banner around the padded part) how big it should be. ALWAYS leave some room for the seams (about 1/2") and a little extra wiggle room.
Instead of just folding it and sewing up the sides (like I did on the padded part) I wanted my sleeve to have a 'bottom'. In order to do this, I came up with a way to fold and sew the bottom so that it would hold a better shape. I first tried it out on a scrap piece of fabric to see if my idea would work. One picture shows the lines I drew to help me figure it out.
After you sew the tricky corners, sew up the sides of the outer part of the bag, making sure to fold over a little flap on the front (so that it looks nicer when you sew it to the padded part).
Step 5: Put it all together!
Slide the padded part into the outer part and sew a line down the back, right above where the front is. Sew another line about an inch above the first, so that the flap hinges better on it.
Here's a tricky part: on the front, you must sew the front of the pocket to the top of the front of the bag.
The flap is lined with corduroy, and is sewn to the vinyl tarp by folding the edges and running a seam down it on all sides. I used paper clips to hold it together while I was sewing.