Common wisdom says you shouldn’t grade up more than 1-2 sizes. For many bigger gals, this would eliminate most vintage patterns. This post will show you how I do it. BTW, I started grading patterns before I knew I wasn’t supposed to. I’ve been asked if grading is hard. It’s not, just time consuming. I will show you how I do it, which may or may not be the “right” way to do it. One important thing to keep in mind is that while I may be a plus sized woman, I am also a petite woman. I am short, fined boned and short waisted. This means that I don’t have to do many of the more difficult parts of grading. I generally don’t need bigger collars, pockets, other design details that a taller plus sized woman might need. Generally speaking, when pattern companies and RTW designers grade up, they grade everything up. Personally, I don’t need larger armholes, longer sleeves, bigger neckholes, longer hems. Therefore, if you are not petite, this “fast and dirty” way of grading might not be exactly what you need, but might at least get you thinking in the right direction.
Here’s what you need to get started: pattern, tape measure, newspaper or pattern tracing paper and pins or scotch tape. You might also want to bring some brutal honesty about your body.
First step: measure yourself at the bust, waist and hip, 7 inches below the waist. Measure the pattern pieces at the same places. Don’t forget to subtract the seam allowances and any pleats, darts or tucks. Write these down. Figure out how much more room y0u need. In the example I’m using, I need to add 8 inches. Because each front and back piece represents half of the completed piece, adding 1/4 inch means you are adding 1 inch to the finished garment. This means I need to add 2 inches to the front and back pieces.
Make sure you transfer all the pattern marks, dots, notches, ect to your traced copy.
Your next step is to cut through your traced copy at regular intervals, then place those sections on more of your tracing medium. In this example, the first copy is newspaper and the second copy will be muslin. I typical place my first cut just outside of the neckline. I prefer to alter my neckline during the muslin fitting stage.
If you use muslin as your second copy, you will be able to use this as a fitting muslin. If you are doing this, use doubled fabric as if you are cutting a pattern in the normal fashion.
Start the grading by placing the center seam or fold section on your tracing medium and pinning or taping in place. Then place the next section on the tracing medium next to that section, leaving the space needed. In this case, because I need to add 8 inches, each section will be placed 1/2 inch apart. After you have laid out all sections on your tracing medium, draw a line around the edges of the spread-out pattern, smoothing the line between the pieces. After you have finished the perimeter, make sure to transfer all markings. You now have your new pattern!
I hope this is clear and feel free to let me know if you have any questions!