Pattern Hacking a Colourblocked T Shirt

When I thought up this project, I really thought it was going to end up being one of my more ‘out there’ shirts, but it turns out to fit quite well into my wardrobe rotation! I think it helps that the colours I chose go with so many things in my closet, but either way – here’s a fun little colourblocked t-shirt project for you if you’d like to add some colours to an outfit!

Materials

A T-shirt pattern of your choice
3 colours of jersey fabric (or as many as you like! Scraps would work well for this.)
Wooly nylon thread for construction seams
Matching thread for hems

I made this project entirely on my bernette 68 AIRLOCK which is an overlocker/coverstitch combo machine. If you don’t have an overlocker, choose an overcast stretch stitch or zig zag on your sewing machine, and if you don’t have a coverstitch, you can hem your shirt with a zig zag or twin needle.

bernette 68 AIRLOCK

Automatic air threader for looper threads ✓ Color-coded theading paths for easier threading ✓ 2-, 3-, 4- and 5-thread stitches ✓ Large slide-on table ✓ 5 LED lights for best visibility ✓ High stitch quality with speeds of up to 1300 stitches per minute ✓ Large cut-offs bin included ✓

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Planning and Prep

The base pattern I started with is one of my own self drafted t-shirts, and we won’t be making any fit changes to the shirt so any t-shirt pattern you have will work for this! I also had my three colours of fabric selected. Each of these is a Merino jersey of around 200gsm – keeping the fabric weights consistent means the shirt will have a consistent drape which is something I wanted, although different weights could also be a cool effect!

After you’ve selected fabric, the next step is to make a map for your colour blocking. I did this by drawing a rough outline of my shirt (I did mine digitally in Procreate, but sketchbooks are great too!) and testing out some different ways to separate the pattern pieces.

I had a few requirements that determined my design, like making sure none of the seams ended in the armscye, and I wanted the colours to match across side and shoulder seams. Additionally, I wanted only straight seams – although next time I think it’d be great fun to throw some curves in there!

This vastly narrowed my options for how to separate my shirt, and I ended up settling on this layout:

Choosing how to distribute the colours was much harder! I made several options with my line drawing, and eventually managed to make a decision (option 2, though I ended up not adding the pocket) and move on to the drafting!

I traced off a copy of my shirt pattern’s front and back (My sleeves are solid colours so I didn’t copy these, I just used the original pattern piece) and made marks at the side and shoulder seams according to my sketch, ensuring that the marks on the front and back pattern pieces were aligned. Then, I simply connected them with a straight line. When you’re drawing your pattern, be sure to transfer the grain lines to each new pattern piece, and mark them clearly so you know which of your new set of very odd-looking triangles is which. You’ll also need to add seam allowance to the slashes to ensure the fit of your shirt doesn’t change.

Cut the pattern pieces according to your colour plan, and then we’re ready to sew!

Constructing the Shirt

Construction for the colour block shirt proceeds in much the same way as a regular t-shirt, the biggest difference is just getting the front and back pieced together before the rest of the assembly.

I used wooly nylon for both the top and bottom loopers for a few reasons – first, it gives great coverage and keeps things nice and neat on the inside, and second, it is softer than regular overlocker thread, and since there are a lot more seams in this shirt than usual, I wanted to make them as unobtrusive as possible. Wooly nylon isn’t terribly difficult to use, but I do have a few tricks I can share that might help you avoid hiccups if you’re using it for the first time!

The b68 is air-threaded, which I love, but the wooly nylon doesn’t always make it through the tubes on first puff. It is possible to air-thread wooly nylon, but I find it much easier to thread a length of all-purpose sewing thread through as a leader, tie the wooly nylon to the end, and pull it through.

Threading the needle with wooly nylon can also be a bit of a headache, and for the most part (as I did here) I just use a regular multipurpose sewing thread in my two needles. You can thread wooly nylon with a needle threader – it takes a bit of practice – and another good option is to run the last 3” or so of wooly nylon through some glue, pinch it between your fingers to pull it through and form a point, and then let the glue dry before threading the needle. I don’t like waiting for glue to dry though! In this case, using regular thread in the needles is just fine – the wooly nylon in the loopers will be enough to soften up our seams.

When sewing with my overlocker, I much prefer clips to pins because it’s impossible to accidentally sew through a clip! To construct the pieces, I joined the small blocks together first (my teal and purple), pressed the seam, and then added the larger (plum) block.

After that, construction proceeds just like any other t-shirt! Just take special care to match up the colour changes at the side seams and shoulder – I pressed my overlocked seams in opposite directions to make these joins less bulky.

I highly recommend stopping between each seam to press them as you go, especially if you have a more complicated colour block design. You’ll end up with odd bumps if your seams need to swap directions!

Once all the overlocking is done, it’s time to swap the b68 to coverstitch mode. I folded the hem of the body and sleeves up 1.25”, pressed, and coverstitched using thread that matched the hem and each sleeve. Again, I used wooly nylon in my looper for coverage, and regular sewing thread in each needle.

My neckband is finished with a coverstitch as well – I swapped to the narrow needle setting for this, topstitched, and there she is! A finished shirt that is quite honestly not as wild as I thought it would be!

Next time, I’ll get a bit more bold in my colour choice and introduce some curvy seams! In the meantime, I’m loving this very wearable, very fun tee in my wardrobe!