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Tutorial and Video by Seamster Sewing Patterns – How to skip hemming the Comox Trunks

Sewing Indie Month

Today, we have a guest tutorial for you, as part of Sewing Indie Month!  Mari, of Seamster Sewing Patterns, is not only the mastermind behind this month’s cornucopia of events, tutorials, and contests, she has also kindly taken the time to contribute a tutorial of her own to our blog.

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She’ll be walking you through how to dye fold-over elastic with food colouring and how to apply it to our Comox Trunks.  The tricks she will be showing you will allow you to avoid using the self-made binding for the fly and to skip the worry of using a twin needle or zig zag stitch while hemming the legs.  These are both of the steps that sewers found to be the most tricky during our Comox Trunk Sew-Along.  Thank you, Mari, for providing an alternative method to finishing these areas of the trunks!

Now over to Mari, who you can thank for making your Comox Trunk sewing life just that much easier!:Seamster Sewing Patterns

Hello Thread Theory readers! I’m Mari and I run Seamster Sewing Patterns. Today I’m going to show you how you can easily dye fold over elastic with simple ingredients you have at home, like food coloring. Then, I’ll walk you through attaching fold over elastic to the Comox Trunks.

Why dye fold over elastic when you can get a lot of colors online? It’s fun! Seriously, I find it really excited to see what colors I can come up with. It’s like finding a spare $5 in your pocket when doing laundry; the color you get can be a total surprise, but a really good one. Dyeing is also a great way to quickly customize a project, make it extra special, and get fun colors you won’t be able to find in your local fabric store.

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Before we begin though, let’s go over a few dyeing basics. 

In this tutorial we’ll be acid dyeing nylon fold over elastic. Acid dyes are one of the easiest dyes to get started with. They involve the use of acid (nothing scary dangerous, just vinegar for this tutorial!) and can be used to dye protein fibers like wool or silk and often nylon. They will not dye cotton or polyester. That is why it’s very important to make sure you’re using fold over elastic made from nylon. How to find out if your elastic is made from nylon? Ask your local or online shop. I bought the elastic I’m using in this tutorial from Peak Bloom. They told me their solid colored fold over elastics are made from nylon, while their patterned fold over elastics are made from polyester. Keep that in mind if you order from them.

The reason why I’m not showing you how to dye polyester is because it’s difficult to do at home. It also necessitates constant, high heat, which would badly damage the spandex in your elastic. Acid dyeing with nylon also calls for heat, but is a little more forgiving. So, we must strike a balance between heating our dye bath (solution of water + dye) with maintaining a temperature below 105F (40.56C) so our elastic doesn’t degrade .

One more thing to note before we get started, you’ll see I’ve been very specific in the list below by specifying the use of wooden, plastic, or stainless steel tools. That’s because certain metals act as mordants, which can change the color of your dye.

Here is a quick reference “recipe card” that Mari made for you to refer to while dying.  She includes a detailed write-up and photos below, so keep reading before you begin your dyeing project!


…And now the full tutorial:

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In order to dye we’ll need a few things:

  • crockpot (you could use a regular pot over a stove, but I find it’s easier to use a crockpot for consistent temperature and because it lets me walk away without worrying about burning the house down)
  • water
  • food coloring
  • distilled white vinegar
  • non-iodized salt (optional, it helps drive dye into fibers, but I only had himalayan salt on hand, so I didn’t use any in my experiments)
  • wood, stainless steel, or plastic stirring utensil
  • plastic gloves (optional, but great if you don’t want to scrub dye out of your hands)
  • glass or stainless steel bowl
  • plastic, glass, or stainless steel measuring cups and spoons
  • thermometer
  • dish soap or synthrapol (special soap used when dyeing)

Here’s my basic dyeing recipe:

  • 1 c water
  • 10 drops food coloring (you can use a couple drops less and still get a brilliant color; for a light color use just a few drops)
  • 1T distilled white vinegar
  • 1yd 5/8” fold over elastic or 2yd 3/8” fold over elastic

For the Comox Trunks I graded from a size 28 to a 34, for which I only needed about 30” of 5/8” fold over elastic to sew to the leg and cup openings. However, it’s best to give yourself a little extra, so instead of 30”, I dyed a full yard, although you may need to dye more.

Because my local fabric store doesn’t carry wide elastic made from nylon that’s needed for the waistband, I dyed an extra yard of fold over elastic to sew on top of my polyester elastic waistband for purely decorative purposes (Morgan: Nice idea, Mari!  What a great way to customize boring waistband elastic by adding strips of colour!).

In total, I dyed 2yd of fold over elastic, for which I doubled the basic dyeing recipe above.

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Here’s how to dye nylon fold over elastic:

  1. Fill your crockpot about 3/4 full with water and turn it on. (I set mine to high, but each model cooks at a different temperature, so you’ll need to experiment)
  2. Fill your glass bowl with water (going by the recipe above) and mix in salt if you’re using it.
  3. Stir in your food coloring and let the mixture heat. This is your dye bath. Once it has fully heated, take its temperature. If it’s well below 105F (40.56C) you may be able to bump your crockpot up to medium or high. If it’s above 105F (40.56C) lower your crockpot to medium or low.
  4. While waiting for your dye bath to heat, wash your elastic. This will get out any chemical residues that could give you an uneven dying job.
  5. Submerse your still wet elastic in your dye bath. It’s important that the elastic be wet before putting it in so that the color will take up evenly.
  6. Pour vinegar around, but not on top of your elastic. Thoroughly stir it in. As you pour in your vinegar you’ll notice your elastic quickly chaining color.
  7. Let your elastic sit in your dye bath until you’ve reached your desired color or until your dye bath is exhausted. Periodically check on it and give it a little stir to make sure it’s as dark as you want it. I usually let mine site for about 1-1/2hrs. A dye bath has been exhausted when the fiber has soaked up all the dye that’s in the water. My recipe is a little heavy on the dye, so there’s usually some left over. Since food coloring is cheap I don’t mind that there’s some extra dye being thrown away at then end.
  8. Wash your elastic. If dyed at high enough of a temperature, there shouldn’t be much dye rinsing out of your elastic. If you’re concerned about more dye leaking out, toss it in a washing machine. Let your elastic air dry.

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If you’d like to know more about dyeing, check out Paula Burch’s All About Hand Dyeing site. It’s a great wealth of information. 

How to add fold-over elastic to the Comox Trunks: 

Now that we have our custom dyed elastic, let’s sew it to the cup and leg openings. Note that the Comox Trunk pattern calls for the leg openings to be hemmed at 5/8″. By binding the openings with fold over elastic the legs will be 5/8″ longer than if they were hemmed. (Morgan: You could simply trim off this extra 5/8″ if you would like to keep your trunks the original length.)

To show you how to sew fold over elastic to the Comox Trunks I made a video tutorial. The technique shown here can easily be used with other knit garments too, like my Yellow Tail Camisole. If you prefer reading over watching, below the video is a transcript with a few extra tips that didn’t make it into the video.

Video Transcript:

Hey everyone! This is Mari from Seamster Sewing Patterns. As a part of Sewing Indie Month, a month long sewalong and celebration, I’ve been working with fellow indie sewing pattern maker Thread Theory to bring you a tutorial on sewing with fold over elastic. 

Fold over elastic is a great way to finish the edges of knit garments. Today I’m going to demonstrate how to do that with Thread Theory’s Comox Trunks sewing pattern. 

For this tutorial I’m using less than a yard of 5/8” wide fold over elastic for the size 34 Trunks. Fold over elastic is like the knit version of bias tape. That means it will fold over on itself to encase the raw edge of your fabric. Before we begin, take a good look at your elastic. See the central groove running down the length of your fold over elastic? That’s the fold line where you’ll be folding your elastic in half. 

Also see how one side is shiny and one is plush? You can use either side. For these trunks I want the plush side to be visible, which also means it will be directly touching the wearer’s skin, while the shiny side will be hidden. 

I’m going to show you how to attach fold over elastic two ways. But if you’ve never sewn with fold over elastic before you’ll definitely want to practice first on a scrap of fabric! 

To begin with, we’ll be attach the elastic to a flat edge, in this case the cup opening on the Comox Trunks. To figure out how much elastic you need, lay the elastic in a straight line alongside the curved part of the cup to which it will be sewn. Your cut piece should be long enough to reach from each end of the cup opening. 

Now for the sewing! Use a wide zig zag stitch for this step. I like a stitch that’s 3 wide by 3.5 long. In this step we’ll be stitching the fold over elastic to the wrong side of your fabric, or what will be the inside of your garment.

Remember that the side of the elastic you DON’T want visible will be the side that directly touches your fabric; in this tutorial that’s the shiny side. Line up the raw edge of the fabric with the central groove in your elastic. That means half of your elastic will be sticking past the edge of your fabric. It’s also easiest to get started if there’s a little extra fold over elastic hanging past the end of the cup opening. That helps prevent your fabric and elastic from getting sucked down into your sewing machine. For easiest visibility while sewing, your fabric should be on top of your elastic and your elastic should be directly touching the throat plate on your machine. 

Once you have everything lined up, begin stitching the two together. Stop after you’ve sewn a few stitches, making sure your needle is still piercing your fabric and elastic. Now gently pull your fold over elastic. It is incredibly easy to stretch out your fabric as you attach your fold over elastic. Gently pulling your elastic helps prevent that and as long as you don’t pull too tightly it won’t gather your fabric. Keep stitching your fabric and elastic together, making sure the raw edge of the elastic aligns with the center groove in your elastic and that your elastic is slightly stretched out while your fabric is feeding through your machine at a normal rate. When you get to the more curved section of the cup opening you may wish to pull on your fold over elastic just a little bit more tightly. 

Now we’ll stitch the front of your elastic to the right side of the fabric. Fold the remaining half of your elastic over the raw edge of your fabric. Stitch it to your fabric using a straight stitch or a very narrow zig zag stitch. When stitching 1/8” or closer to the edge it’s called edge stitching. If you’re using a contrasting colored thread like me, you may want to break out an edge stitch foot if your machine has one. That way you can more easily edge stitch a nice, straight line. And that’s all there is to it!

Next, I’ll show you how to sew fold over elastic in the round to a garment’s opening, like a sleeve or neckline. In this case, we’ll be binding the leg openings of the Comox Trunks. 

Before we begin, we’ll need to determine how much elastic to cut. Lay your assembled trunks on the table. Like we did when cutting elastic for the cup opening, we’ll lay our fold over elastic out in a straight line, from each edge of one of the leg openings. Double that length and cut your elastic. Next, fold your elastic in half, right sides together. Using a 3/8” seam allowance, straight stitch the raw ends of the elastic together. Do this for each leg’s elastic. 

Your fold over elastic will be smaller in circumference than your leg openings. So, mark your leg openings and fold over elastic at four evenly spaced points. Then, pin the elastic to the leg openings at those marks. See how the leg openings are larger? It’s important to evenly pin the elastic and fabric together so that the elastic evenly stretches to meet the fabric. 

Same as before, we’ll stitch the fold over elastic to the wrong side of our fabric. What we’ve got to watch out for here is that the raw edges of the elastic’s seam allowance don’t peek out. Now, stitch the elastic to your fabric using the same 3 x 3.5 wide zigzag stitch as we did when sewing the cup opening. After you’ve sewn a few stitches, stop with your needle piercing your fabric. Then grasp your fabric and elastic where the next pin is and pull until the elastic is the same length as your fabric. Sew the elastic and fabric together, remembering to align the raw edge of your fabric with the central groove of the elastic. Keep sewing like this until you’re back to where you started. 

After that, switch to a straight or very narrow zig zag stitch. Fold your elastic over the raw edge of your fabric. I like to start stitching a little bit before the elastic’s seam allowance so that I’ve got a few stitches anchoring things down. Often when I get to this side the fold over elastic’s seam allowances will be peeking out. So, I’ll tuck them under. Using a seam ripper helps since the seam allowances are so small. Once your seam allowances are no longer visible, keep sewing around the garment’s opening until you’re back where you started. 

That’s it! Simple, easy, fast, no annoying stretched out edges.

To make your own Comox Trunks, go to, where you can also find another tutorial by me on how to dye your fold over elastic.

To see what other great tutorials and hoopla is going on around Sewing Indie Month, head over to

Thanks for watching and happy sewing!   


Thanks Morgan and Matt for having me on your blog! And happy Sewing Indie Month everyone!


Looking for elastic for your Comox Trunks?

Happy Friday!  This post is going to be a little bit of an update on all sorts of things…our sew-along, an elastic shopping resource, and a look at what’s on my sewing table right now!

First off, remember to submit your entry to our Comox Trunks sew-along contest by May 5th for a chance to win this awesome kit of everything you need to sew an underwear drawer full of trunks!  You still have time (especially since it only takes a couple hours to sew these bad boys and the PDF download is instant.IMGP7128

Next on the agenda is something to further inspire you to sew those Comox Trunks: A source for awesome elastic!  I have noticed a lot of people mentioning that they have struggled to find nice elastics to add to their Comox Trunks.  Some people have even resorted to re-using elastic from old store bought trunks (an awesome idea but sometimes that’s the part that wears out first on underwear so that idea may or may not help you out…).  If you can’t find elastic locally, never fear, there are great online options!  And shipping is quite cheap too because elastic is so light and makes for a very small parcel.

One of our stockists, Mrs. Bao recently let us know that they have just added a whole selection of Comox Trunk worthy elastics to their shop.  Just have a look at these interesting options – all are a far cry from boring white or black!
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All photos link to the product so just click on them to check out more information.  I’m thrilled by the width of these elastics, the quality of the photos (it is easy to see that they all look to be quite soft and appropriate for underwear) and the reasonable prices (both for the elastic and shipping).  Even with shipping, most of these elastics are still cheaper than I would pay at my local fabric store!

Okay, now lets move on to the final update of the day – here is what is on my sewing agenda for Sewing Indie Month!

I’m providing a tutorial for Tilly and the Buttons later this month so I’ve been busily searching for inspriration and sewing her Coco pattern.


I mentioned and showed you photos of my first version in yesterday’s blog post:


I’ve got two more in the works which are inspired by Antrhopologie tops.  Aren’t these pretty?

My tutorial will be posted on Tilly’s blog on May 19th, but in the meantime you can look forward to a tutorial by Mari, from Seamster, on this blog.  It will be posted on May 7th…not long now!

Have a lovely weekend everyone – hopefully at least part of it will be spent sewing some Comox Trunks!

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Sewing Indie Month is here!



Today marks the first day of Sewing Indie Month!  Haven’t heard of this amazing, month long celebration of independent pattern designers yet?  That’s because this is it’s first year and it is going to be SPECTACULAR.  This month will include dozens of behind-the-scenes designer interviews, loads of tutorials relating to indie patterns, and most excitingly, the biggest sew-along that has ever existed complete with loads and loads of prizes!

If you are in doubt of just how awesome may is going to be, have a quick look at how many indie companies are involved:


Here are links to the websites of all of those companies so that you can easily check up on them to see what great things they are posting throughout the month:

I will be posting tomorrow about the interviews, tutorials, and sew-alongs that I will be involved with so that you can look forward to what you will be seeing on this blog for Sewing Indie Month and where you will see tutorials and information about Thread Theory patterns popping up on other blogs.

The mastermind behind this event is Mari from the indie sewing pattern company, Seamster.  She deserves a big round of applause and lots of appreciative emails and comments because she has worked incredibly hard planning this for months and I am sure it will go off without a hitch solely due to her high level of organization and her devotion to the project.

So are you curious about how to get involved?  Apart from simply enjoying the many different articles and tutorials that will be all over the sewing corner of the internet, you can grab yourself a button for your blog:

Sewing Indie Month
<div align="center"><a href="" title="Sewing Indie Month"><img src="" alt="Sewing Indie Month" style="border:none;" /></a></div>
…AND…most excitingly, you can join in by sewing along!  Without further ado, here is the information all you sew-along and contest enthusiasts are waiting for:

sewing indie month sewalong rules

The sew-along hosts to whom you will be submitting your entries are the following well known bloggers.  Check out their sew-along announcement pages:

And now that you know how to enter, you’ll probably be wondering, well what are the prizes?  Here, broken down into the four categories, is what you could win!


  • 1 year subscription to SewNews magazine
  • A 2013 Threads Archive DVD from Threads Magazine
  • 1 class of your choice from Pattern Review
  • The Sassy Librarian Blouse Craftsy class by Sewing Indie Month designer Christine Haynes
  • The Sewing Indie Month designer prize pack: PDF pattern of your choice from Stepalica Patterns; PDF Nettie Dress & Bodysuit by Closet Case Files; PDF Twisty Top Pattern by Soma Patterns; paper pattern of your choice from Tilly and the Buttons


  •  1 year subscription to Sew News Magazine
  • 1 year subscription to Threads Magazine
  • $25 gift certificate from The Smuggler’s Daughter
  • Sewing Vintage: The Flirty Day Dress Craftsy class by Sewing Indie Month designer Sew Chic
  • The Sewing Indie Month designer prize pack: PDF pattern of your choice from Lolita, Pauline Alice; paper pattern of your choice from By Hand London, Christine Haynes


  • 1 year subscription to Sew News Magazine
  • Sew Smarter, Better and Faster book from Threads Magazine
  • $30 gift certificate from Girl Charlee
  • $25 gift certificate from The Smuggler’s Daughter
  • Comox Trunks Supplies Kit from Sewing Indie Month designer Thread Theory
  •  Sewing Indie Month designer prize pack: PDF pattern of your choice from Maria Denmark, Sew Caroline; PDF Duathlon Shorts by Fehr Trade; paper pattern of your choice from Sewn Square One


  • 1 year subscription to Sew News Magazine
  • 1 class of your choice from Craftsy
  • £20 gift certificate to Minerva Crafts
  • Hot Iron Transfer Embroidery Pack from Sewing Indie Month designer Kate & Rose
  • Sewing Indie Month designer prize pack: PDF pattern of your choice from Seamster Sewing Patterns, Sinbad & Sailor; PDF Movie in the Park Shorts by Dixie DIY; PDF or a paper pattern from Skinny Bitch Curvy Chick

Bonus Winner!

A Bonus Winner randomly drawn from all the sewalong participants will win the following prizes:

  • 1 year subscription to Sew News Magazine
  • $75 gift certificate from Britex Fabrics
  • 1 year Friends of PR membership from Pattern Review
  • Love at First Stitch signed book by Sewing Indie Month designer Tilly and the Buttons
  • Sewing Indie Month designer prize pack: PDF pattern of your choice from Waffle Patterns; PDF Wardrobe Builder Pack by Thready Theory; paper pattern of your choice from Kate & Rose, Sew Chic


A pretty astounding list of prizes!  Thank you very much, on behalf of all the Sewing Indie Month pattern companies, to the amazing array of sponsors who have donated these prizes!  Here are their logos (as well as some of the prize images) so you can see just how many generous companies are involved (click on the logo or prize image to be taken to the company’s website):

1 year subscription to Sew News Magazine

2013 Threads Archive DVD from Threads Magazine

1 class of your choice from Pattern Review

Sassy Librarian Blouse Craftsy class by Sewing Indie Month designer Christine Haynes




$30 gift certificate from Girl Charlee

Comox Trunks Supplies Kit from Sewing Indie Month designer Thread Theory



Kate and Rose Embroidery Pattern Pack


Love at First Stitch signed book by Sewing Indie Month designer Tilly and the Buttons

I know I am looking forward to May!  Are you?  Do you have plans to submit an entry to one of the sew-alongs?  I hope we will see some menswear garments as entries!