Layout is critical for getting maximum bags with zero waste. I always spend some time measuring, calculating, and drawing out on paper how to cut out as many sets of gussets and panels as the yardage will let me. Panels don’t vary in size. Gussets, however, while always the same length, can vary in width, depending on the available yardage.
To help explain what I mean, let me take you through the process.
I had a piece of scrap brown floral/paisley fabric in my stash. I laid it out on the floor to measure. I have 118 inches (about 3¼ yards) of 45-inch-wide fabric. That translates out into several sets of bags, both side panels and gusset.
Before measuring the cloth, I pulled threads from both raw edges, ensuring that I started with a straight edge, on the grain. Fortunately, this piece of fabric had been cut straight to begin with. Some yardage could have a cut edge that’s wavy, cut at an angle, or very uneven. That translates into less actual fabric you can use.
These tailored bags I make consist of a front or side panel, a back or side panel (both the same dimensions) and a gusset that connects the two sides from top edge, all the way around and back up to the top edge on the other side. That is, each cloth grocery bag is made of three pieces of fabric. The pair of handles are made from webbing, so I do not need to reserve cloth for them.
Each panels will be 13 by 15 inches. My gussets are going to be 43 inches long and the width will be what the fabric wants to divide into, but no less than 8 inches wide.
Gussets seem to work best if they are about 8 inches wide. Seven inches is getting narrow, so you never want to cut less than this. Nine inches is getting too wide, resulting in a square-bottomed grocery bag.
The length of the gusset is calculated by adding the length of both sides plus the bottom. That is, if your side panels are 13 inches wide and 15 inches tall, you will need a gusset that is 15 inches plus 15 inches (the two sides) plus 13 inches (the bottom measurement) for a total length of 43 inches. This gives you a margin for error as this measurement is a little too long; I have found through sad experience that you don’t want to cut your gusset short in an effort to save expensive cloth. I end up sewing in a patch.
If you make your side panels a bit larger, say, 16 inches tall and 14 inches wide, you will need to make your gusset correspondingly longer: 16 plus 16 plus 14 or 46 inches long.
I have my handy charts showing me that I can cut three panels, each 15 inches long, from a 45-inch width of fabric, if I stack them, one on top of the next. There will be zero waste, assuming that I include the selvedges in my measurements. I nearly always do include the selvedges unless they are woven too tightly to be used, distorting the sides of the cloth. Most of the selvedge will be concealed within the hems so it won’t show, or at most, it will show as a narrow line on one side of the panel. Selvedges included as part of the gusset never show because of the way the bags are constructed.
A brief talk about kerf
As I calculate out how many panels and gussets I can cut, I also keep track of kerf. Kerf is a carpentry word, and it means the thickness of the saw blade. When you cut wood, you have to measure and mark your line, cut the part off, and then measure and mark the next cut. Never make all your measurements followed by all your cuts because the first cut will eat up a bit of wood, enough to throw off the final size.
While scissors and rotary cutters have a much smaller kerf than a saw blade, there is some and it does accumulate over many parallel cuts in the width of a long piece of fabric. I always allot a few inches over what my measurements indicate I need to allow for this.
Fabric is also used up when you pull threads (for those unfamiliar with the phrase, that’s when you carefully isolate a single thread and pull it out of the fabric, leaving a small gap. Cut along that line, and you’ll have a perfectly squared-off edge).The width of two pulled threads doesn’t seem like much, but again, when you pull threads, in parallel sets across the length of a piece of yardage, it adds up and you find yourself with that last set of panels being a little smaller than you had planned on.
Drawing a picture
The brown paisley fabric does not have a definite direction so I can use the most economical layout for my panels and gussets. This is readily apparent in how 45-inch-wide fabric divides nicely into three 15-inch-panels, each 13 inches wide. It doesn’t divide nearly as well into 13-inch-panels, leaving me with a 6-inch wide strip that is too narrow to use for anything else. (13 times 3 is 39. Forty-five inches minus 39 inches equals a 6-inch wide strip.)
So I start by drawing a very rough sketch:
I drew my rectangle and started drawing in my gussets on the right and my panels on the left. Panels must always be in pairs. I started with estimating the width of the gussets. Nine inches is too wide and it eats more fabric than 8-inch-wide gussets. That is, six 9-inch gussets needs a total of 54 inches, whereas six 8-inch gussets needs only 48 inches in width, a difference of six inches.
Starting at the panel side, if I lay my panels one on top of another, I can get three 15-inch panels, each 13 inches wide. Two columns of panels will eat 26 inches, and give me three bags. Two more columns of panels will eat another 26 inches and give me three more bags, for a total of six bags (12 panels). Six columns needs 52 total inches of fabric.
It looked like, from my sketch, that I would have about 12 inches left over, after cutting 12 panels (four columns worth) and six gussets, each 9 inches wide. Twelve inches is awfully close to 13 inches in width. If I cut my gussets narrower, I could get another full column of panels, giving me seven bags and one panel left over for the Frankenstein pile.
(One reason to standardize the size of your tote-bag panels is to put any excess into a pile from which you can make more bags, instead of throwing the fabric away. You can also piece smaller fabrics to make a panel, hence the name “Frankenstein bag.”)
So that is what I did. I started at the straightened edge and drew a chalk line 13 inches in. I cut a 13-inch-wide column, then cut this into three panels, 15 inches in height. I repeated this action until I had cut five 13-inch-wide columns in all, cutting each column into thirds. This gave me seven pairs of panels with one left over.
Cutting the gussets
The remaining fabric was ready to be turned into gussets. The gussets were oriented to run from selvedge to selvedge as they are 43 inches in length, fitting nicely within the 45-inch-span of fabric. I went back and forth on how to do this. Subtracting 65 inches from 118 inches gives me 53 inches of cloth for the gussets. I can’t cut them 9 inches wide. Dividing 53 inches by seven (that is, seven gussets) gives me 7.57 inches, a difficult measurement to make. Dividing 53 inches by six (that is, six gussets) gives me 8.83 inches each.
I chose six gussets simply because it was easier to cut them. When cutting gussets, remember they don’t have to be exactly the same width; length is what matters. I didn’t have to measure 8.83 inches. Instead, I ironed the piece of fabric flat, folded it exactly in half, and then cut up the fold line. That gave me two identically sized pieces of fabric. I measured off 8-5/8 inches, drew my chalk line and cut that gusset. I folded over the remaining piece of cloth and cut along the fold line, giving me two more gussets, each the same width; they were about 8 5/8 inches wide.
I repeated these actions with the other piece of fabric. This gave me six gussets, each about 8 5/8 inches in width. This does mean that I have one extra pair of panels, along with a spare panel for the Frankenstein pile.
My other choice, the one I did not make, was to measure a gusset 7-5/8 inches wide, then ironed the remaining fabric, folded it and cut along the fold line. That would have given me two pieces of fabric, that could have been cut into six more gussets, each about 7½ inches wide. It felt too narrow so I didn’t do it.
This is the kind of decision that you will make over and over, when trying to squeeze out every gusset and panel possible from a specific piece of cloth. I am not too concerned about having spare panels laying around as I have a pile of them already (along with plenty of spare gussets) and plan to convert them all into Frankenstein bags. You may not want to do this. Frankenstein bags, while just as functional as a bag made of a single kind of cloth, do look odd. Very odd sometimes, particularly when the panels and gussets are pieced. If you don’t want too many leftover panels and gussets, then I recommend that you choose the narrower gusset width, but do not go narrower than 7 inches.
Once you have cut your panels and gussets, it is time to sew them up.
(This post is a draft from the upcoming book “Sewing Cloth Grocery Bags.” A complete list of the posts can be found here.)