How to Construct Undies with a Serger and FOE

Here we go people, the very thing that you've been asking for and I've been promising to deliver: a how-to on pants/knickers/panties/undies construction. After a fair bit of examining my shop-bought pants, I did some experimentation with different construction methods and types of underwear elastic (a lot of which has been previously documented on this blog) to work out how best to make my own. This is my favourite technique for creating great-looking and comfy pants!

Materials:

• Pants pattern. Either make a pattern by tracing or deconstructing an existing pair or download my hipster pants pattern (to be uploaded to Burdastyle in the near future and available for free download). Make sure there are three pieces: front, back and gusset
  
• Knit fabric. You can upcycle old T-shirts or use any piece of pants-appropriate knit fabric. Remember, standard crew-neck T-shirt fabric tends to have less stretch quality than a lot of knit fabric (particularly those with an elastane content), so you may want to add an extra 0.5 - 1 cm at each side seam if you want to use the less-stretchy type to give yourself an extra 2 - 4 cms in total for comfort.
  
• FOE (fold-over elastic). You can use any type of elastic you please, but seeing as I prefer FOE for it's ease of use and clean finish, that's what I'm using for this tutorial. It is available in some haberdashers, and many ebay sellers stock it in a variety of colours and finishes.
  
• Serger/Overlocker
  
• Standard flatlock sewing machine that can make a three-step zigzag stitch or normal zigzag stitch.
  
• Thread
  
• Large handstitching needle

Step 1:

Serge/overlock the top edge of the gusset to create a neat finish.

Step 2:

To create the main gusset seam lay your pattern pieces on top of each other as follows:
Lay the front piece right side up. Lay the back piece on top with the wrong side up. Lay the gusset piece on top with the wrong side up.

Step 3:

When the edges are lined up, pin the layers together.

Step 4:

Serge/overlock them together making sure you catch all three layers in.

Step 5:

Open out the pieces so the front and back pieces are lying wrong side up and the gusset is positioned towards the front with the right side up. The seam will be hidden inside.

Step 6:

Pin the sides of gusset to the front piece.

Step 7:

With the right side up, start at the side seam and apply FOE around each leg hole. The FOE folds in half and traps/sandwiches the fabric edge inside it. Using a three-step zigzag (or a normal zigzag if your machine doesn’t have the three-step) topstitch along the FOE. I usually use a 90-gauge sewing machine needle and haven’t had any problems before.

I would recommend practicing with the FOE and scraps of your fabric until you feel comfortable with this process. It can be a good idea to very gently pull the elastic as you are stitching to create snug-fitting pants. The sides of the gusset will get sandwiched in between the FOE as you stitch (don’t forget to remove the pins as you go!).

Step 8:

You should now have two elastic bound leg holes!

Step 9:

With the right sides together, serge/overlock one of the side seams together. Don’t forget to leave tails of thread, you can stitch these in later to create a neat finish without the risk of unravelling.

Step 10:

Now it’s time to apply FOE along the waist edge of your pants. Just as you did with the leg holes, start at one end with the right side up and sandwich the edge inside your FOE, topstitching with a zigzag stitch as you go.

Step 11:

With the right sides together, serge/overlock the final side seam together.

Step 12:

You should have three tails of thread hanging loose, one at the bottom of one side seam, and two at the other side seam (one at the top, one at the bottom). With a large handstitching needle, like a wool needle, thread the tails of thread back inside the seam overlocking so that the ends cannot be pulled out.

Ta da!!!!! Finished pants! Don’t forget, you can add anything, for example, lace, ribbon, small buttons, appliqués, bows, ruffles, embroidery, ricrac etc. to make your pants super-special!

If you need any stage of this how-to clarified, please leave a comment on this post and I'll try to demystify my meaning! If you don't have a serger/overlocker, don't fancy making or downloading a full pants pattern or don't feel like acquiring FOE, I would recommend Cal Patch's Make Your Own Underwear how-to for a slightly different approach to the one detailed above. Good luck and happy undies making!