Friday, January 28, 2011

From Pattern To Purse: Phase Two, Creating the Pattern

(Not the bag I'm describing here, but I thought it would be nice to have something pretty to start the post.)

Here's the bag I'm making a pattern for:
 Before you start it would be helpful to pull out your sketch and graph paper drafts of your purse design.  Keep them with you to refer back to often as you create the pattern.

Last week we left off with a list of all the pattern pieces I would need to make my slouch bag.  As a refresher, I'm going to be making these pieces:

For the slouch bag we need:
2 large rectangles for the outside
1 oval base
2 straps for the sides (measuring longer so we can attach the D rings)
1 center strap finished measurement about 7 1/2"
1 center strap that will wrap from the bottom back of the bag all the way around to the front
1 handle, 20-24"  (gotta ask the girl what she wants)
3 D rings
1 clip or metal closure of some kind

For the lining:
2 large rectangles
2 zipper pouch pieces
1 pocket piece
1 12" zipper

You need to evaluate your graph paper sketches the same way.To figure dimensions we'll add 1/2" to each side for seam allowance.  Most clothing patterns have 5/8" seam allowances but I like 1/2" on the bag patterns I make because I like lazy math.   With a seam allowance all the way around the rectangle of my bag will be 1" longer and 1" wider than the finished measurement, or 16"x13".   I can draw out a rectangle on my pattern fabric for that.   Then I mark how many of what fabrics I need to cut with that piece.   Usually you need a front and back out of your outside fabric, 2 lining pieces, and 2 interfacing pieces.   Write all that down on the new pattern piece itself just like a commercial pattern has those things listed on the pattern.  When you write it down, you don't forget what needs to be done so you don't have to redo your work.

The accent straps up the side are easy to figure because they go the full height of the bag, or 15".   I'll need 1/2" at the bottom for seam allowance and I want an 1" at the top to sew the D ring in.   All together that means the strap will be 2 1/2"x16 1/2".   Does your bag have accent pieces like this?  Stop and figure out how much fabric you need for them.  If you are sewing in D rings, you can always have the piece be a little longer than you think you need, just in case.   If you are sewing patch pockets on the front, you will probably only want a 1/4" seam allowance around three sides and 1/2" to an 1" at the top edge.   Pockets sewn into the seams will need the same seam allowance you've added everywhere else.   If you've sewn a bag that's similar to the one you're making now, look at that pattern for pattern ideas.   How did that pattern work?  What pieces did it use and did it work for you?

For the strips that go around the middle of the bag, I'll need to slightly more complicated math.  Just slightly, though.   The strip on the front will have 1/2" seam at the bottom and add another 1" to sew in the swivel clip assembly.  Since I want it to reach half way up the front of the bag, that means the finished measurement is 7.5".  So the pattern piece is 2 1/2"x 9".  (finished measurement+bottom seam allowance+top seam allowance.)

For the wrap around strip, I want it to have it start at the bottom of the back side.  It will reach all the way up the back (15") and then wrap around the front to attach to the clip (7.5").  I'll need 1.5" for the seam allowance. The clip is 3" (including D ring).  I want the strap about 3" shorter than it would need to be to reach around.  So the math is 15+7.5+1.5-3-3=18.   Now, the strap will be seen from both sides, so I'll want two pieces sewn together for this one.

Here's those four pieces all drafted out.  Notice I've got my quilt cutting mat underneath my pattern fabric.  The grid shows through quite well and keeps my corners square and my lines straight.  I do use my quilt ruler to draw the lines so I can measure as a mark and be sure I'm getting perfectly straight lines.  

For my bottom piece, I want an oval.  I like the softness the round shape will give to the bag and it will be easy to sew on this bag that has no separate side pieces.  To start I'm going to draw a guide for the oval shape.  It will mark the widest and longest points of the oval.  For this bag I want a finished measurement of 4"x11".  This will make the bottom actually smaller than the width of the bag.  This will soften the lines of the bottom of the bag.   It will also make drawing the oval easier because I'm gathering fabric into it.  I don't have to worry about making the bottom the same circumference as the bottom of the bag.   The guide will measure 5"x12" to allow for seams.

Next, I will sketch in the curve on one quarter of the guide.  I just lightly work with my pencil until I get a curve that satisfies me.  I'll need to be careful to get the ends nicely rounded so the oval doesn't resemble a football.  When I'm happy with it, I darken the line I like best so it stands out from the rest.

Next I mountain fold my pattern fabric.  (origami term.  Fold the wrong sides together here so the pencil marks are on the outside not the inside of the fold.)  Then I trace the line.

Mountain fold the fabric in half the other way and trace the half oval.

Open it up and I should have a full oval on the front of my pattern fabric.
Now mark on your bottom piece what fabric needs to be cut with this pattern piece.  For the bottom we need one from the lining, one from the fabric, and one interfacing.

There's a lot of calculation in pattern making.  You need to know how much fabric it takes to do what you want.  Use your rulers and tape measures to get a feel for size and shape.  Work with the numbers and if you need to, cut a sample piece out of cheap fabric to see if it will do what you want it to do.  Adjust your pattern as needed to make everything work.  It's always best to start with something simple, like a rectangular bag, so you can get a handle on the basics before you jump into the more complicated stuff, like curves and gathering.

For the lining I already know I'm going to have two pieces the same size as the outside of the bag and that is marked on the pattern piece.  Now I need to calculate and cut my pocket pieces.   I want pockets on one side of the lining and I want it to reach halfway up the bag so the finished measurement is 12"x7.5".   Add in the seam allowance and that makes the piece 13"x8.5.    For the center pocket I want it to be the same width as the bag and reach about halfway up, so I'm going to cut it the same size as my side pockets, 13x8.5.

I've decided on a 24" handle that will be 1.5" wide (for now.  I can change my mind on this at any time.  The handle will be sewn last.)  I like two piece handles rather than one piece that's folded in half.  I also use 1/4" seams on my handles because I'm too lazy to trim seam allowances. That means I'll want two long rectangles measuring 25"x2".

Just so you know, most of the time when I'm making a purse pattern I do not make all the pattern pieces.  I make the ones that curve or are more complicated, but the basic rectangles just get listed in my directions for the bag so I know what to cut.  Since I use my quilt cutting tools, I really don't need the pattern pieces.   You can do this as well, but be sure to fully document exactly what pieces you need and what size they should be.  You can mark this in a set of directions that you keep with the other pattern pieces.  I'm drawing out most of my rectangles partly because there are so many of them and partly to demonstrate the process of creating the pattern. 

I've shown you how I go about creating a pattern.  Some patterns will have lots of pieces, some will have very few.  It's all in the design of the bag.  Don't be afraid to look at other patterns to get a feel for how the pieces are shaped and how the bag is constructed.   If you've got an old bag you don't mind destroying, cut it apart so you can see what the pieces look like flat.  Look for construction details that tell you how the bag was put together and why the pieces are shaped the way they are.   Next time you are out shopping, take a detour into the bag section.  Inspect the bags.  Flatten them out.  Count the pieces that were used to make it.  See if you can figure out how they added a particular detail you like.  Look for accents and shapes that appeal to you that you can put into your bags. 

Have fun with this.   Don't stress over the pattern because next week we will get to tweak and perfect as we make the mock up bag.   Have a good week and see you next Friday for part three.   (Or you can show back up all week to read my other posts.  It's ok.  I love visitors.)


  1. Hi Amy,
    I wanto to thank you so much for teaching us so many things.
    Your purses are all very beautiful.
    Kisses, have a nice week.

  2. Thank you! I do think purses are my favorite thing to sew. It's very satisfying. :)