These Tips may seem like the “long way around”, but ignoring these vital steps actually creates a lot more work… or a badly-finished bag!
1. It’s worth buying good bag patterns (…unless you know how to make very accurate bag patterns).
Patterns are made to fit together as a bag should - the seams all match, the lining is the correct depth for the bag, and all the details are marked where they need to be on the bag. Without an accurate pattern, the pieces may not come together as they ought, and because bags are quite small objects, these kinds of pattern mismatches stand out alarmingly. Often the only option is to unpick and recut the offending piece, or the whole bag.
Using a pattern reduces the likelihood of having to unpick, re-cut or disguise mistakes, and you can make the same bag over and over and know that it’s going to work every time. If you start with a paper pattern, you also have a clear point of reference to work from if you want to tweak the design slightly.
2. Take care to identify each pattern piece.
a) If you draft your own patterns, or copy them from a book, it’s worth taking the time to carefully label each pattern piece with grain lines, notches, identification labels and cutting instructions
b) Before you begin laying out your pattern for cutting, make sure you know what each piece is, and which fabric you will be cutting with it.
c) Separate the pattern pieces into groups according to the fabrics they will be used on.
d) As you lay out the patterns on each piece of fabric, make sure you know which way each piece will sit on the finished bag, and cut them according to the correct fabric direction or print placement.
e) Make sure that the grainline is running parallel to the selvage edge of the fabric.
Read the pattern pieces carefully! Unlike most garment patterns, which have obvious body shapes to tell you what they are, bag pattern pieces are often not easily identifiable. They are usually abstract or geometric shapes, and it’s easy to mistake one piece for another.
It’s also important that you recognise which is top and which is the bottom of a pattern piece. Apart from reducing confusion when you’re actually sewing the bag, you have to be aware of directional patterns and naps in the fabric. You may have to think about matching stripes or carefully placing a print detail.
Cutting a bag piece on the right grain is important. The strength of a bag often relies the strength of the straight grain, and stripes, prints and decorative weaves all need to be cut following a consistent grain.
You can waste a lot of time and fabric by cutting the wrong piece in the wrong fabric, or in the wrong direction. Taking the time to make a few checks beforehand may save you hours of unpicking and re-cutting.
3. Use Fabric Efficiently
Before pinning out a pattern, get all the pieces for that fabric and move them into the most efficient arrangement (or “lay plan”) that you can. Try a few different lay plans if necessary, and see which one uses the shortest length of fabric (and creates the least amount of unusable scrap).
When you cut fabric on the fold, start arranging your pattern pieces from the outside (selvage) edge first. Any leftover fabric will be on the folded edge, and therefore twice the width than if it was cut on the selvage, and much more usable for another project.
It’s good practice not to waste fabric. You never know when you might have to re-cut a piece, and you never know how much you’ll need for your next project. Aim to have as much left over as you can to cover all possibilities.
4. Cut out the pattern accurately. Use pins and sharp scissors when you cut out bag pieces. Aim to cut as close to, if not ON, the cutting line of the pattern.
Once the pattern is cut out and taken off the fabric, you no longer have a line to show you where to sew. You have to gauge where to put the seam by knowing the seam allowance depth from the outside edge of the fabric. If the outside edge has moved a few millimetres out, though bad cutting, then the gauge for your stitch line is out.
Even on a simple two-piece bag, if you’re a few millimetres out on each cutting line it can add up to be as much as a centimetre out around the top of a bag. On a bag with more seams, the margin for error increases. It can be too big to fit to the facing or lining, and this leads to puckering, stretching, unpicking and/or re-cutting pattern pieces.
You can spend much more time unpicking and re-doing than the time it takes to pin and cut the pieces carefully.
5. Follow the pattern instructions for cutting notches and marking dots on your fabric.
Because the individual pieces of bags are often geometric or abstract shapes, it’s not easy to tell which way is the top and which is bottom, and where bag pieces join others. Once you’ve cut and unpinned your pattern, notches, nicks and dots are the only guidelines for identification, alignment and the placement of pockets or details. Without them your bag can end up being quite misshapen.
6. Sew at the correct seam allowance depth.
a) If there are notches on the pattern to mark the depth of the seam allowance, mark them onto the pattern piece as you cut it out, and USE THEM (!!!) as a guide to where to start each seam.
b) At the beginning of a seam, put the needle through the fabric at the correct seam allowance, and line up the edge of the fabric with a fixed point on the sewing machine – whether that’s a seam guide (one of the lines on the machine bed) or the edge of the presser foot. Keep your eye on this fixed point, and keep the cut edge of the fabric travelling evenly along it as you sew the seam.
One of the most common reasons for bag pieces not fitting together is that the seams are sewn in the wrong place (ie. at the wrong seam-allowance depth).
The matching seamlines of a bag pattern are designed to be exactly the same length, to make the pieces of the bag all fit together smoothly. If you sew with the wrong seam allowance – or an inconsistent, uneven seam allowance – you are often trying to sew the fabrics along completely different lengths. This can mean that the bag pieces themselves will appear “too short” or “too long”. It may create a “twist” in the bag, as front and back no longer sit square.
Because bag patterns have lots of seams that transect other seams, it’s important that all the pieces are sewn accurately if they are to fit. For example, facings and linings each have to be sewn with exactly the same seam allowances as the outside of the bag, otherwise they will be too large or small to fit to the bag around the top seam. Fabric may have to be stretched or puckered to sew the pieces together.
Sewing with inconsistent or uneven seam allowances can create results similar to inaccurate cutting. If you have a combination of inaccurate cutting and inaccurate seam allowances, it can be disastrous.
7. DON’T trim off “leftover bits” when seams don’t fit together.
If a bag piece appears to be a different length than the piece to which it is seamed –
a) Check the seam allowances to make sure they are accurate.
b) Check the notches to make sure they match.
c) Check that the fabric piece is the same size as the paper pattern piece.
d) Check that the seamlines on the patterns are the same length.
e) Unpick the pattern piece and correct the problem.
If you have “leftover bits” of fabric at the end of a seam, it usually means that your cutting or your seam allowances are inaccurate. Occasionally it may mean that the pattern is inaccurate (see TIP No. 1). It can also happen when notch points and pins are not used, and one piece of fabric has stretched slightly with sewing.
By randomly trimming pieces off, you exacerbate the problem by changing the shape of the bag piece. Other pieces of the bag may then not fit to it. If it comes together at all, the bag will end up being misshapen, and there’s a good chance the lining wont fit.
8. Always secure the ends of each seam with “back-tacking” or “back-stitching” (a few reverse stitches) to stop it unravelling. Don’t simply tie the ends of the threads together.
Making a bag involves a lot of fabric manipulation and seam-allowance clipping. As you fit together lots of small pieces, and turn them all through to the right side (through a small gap in the lining), stress on the seams can be cause the ends to pull apart if they are not locked together securely.
If they are not secured properly, the seams may even split AFTER the joined pieces have been attached to another piece by a transecting seam (for example, the side seam may split at the point where it meets the facing or lining). It takes longer to unpick the transecting seam and sew the side seam again than it does to secure the ends of the side seam in the first place.
9. At the end of each seam, clip away the corners of the seam allowances.
Start about 3cm (1 ¼ “) from the end of the seam, and clip towards the end of the seam. Don’t cut the stitches – clip towards a point about 1-2mm away from the last stich of the seam.
Bags have a lot of seams converging at particular points. If the seam allowances are left whole they add bulk to these points, and can make it difficult (or impossible) to sew through all the seams. The bulk of the seam allowances may also be seen from the outside of the bag as an ugly bulge.
By clipping the seam at the angle described above, you will reduce bulk in the seam allowance, while leaving enough fabric to effectively press the seam allowance open (see below).
10. Press each seam allowance open as you sew the bag together. Don’t leave all of the pressing until the bag is finished.
Pressing the seams open creates clean, smooth lines on the bag, and it makes shapes easier to turn through to the right side. It makes smooth surfaces for topstitching. Good pressing can be the difference between a bag that looks amateurish and one that looks well finished.
As the bag comes together, you are creating an increasingly enclosed shape, and it becomes increasingly difficult to access all the seams with the iron. By pressing as you work, it’s easier to completely flatten all the seams properly, and reduces the time spent on a “final press” when the bag is finished.
credit to: Nicole Mallalieu