Aurifil 40 wt Thread Vs Aurifil 50 wt Thread
Aurifil makes the highest quality cotton quilting threads on the market, and their leading weights: 40 wt and 50 wt are both beautiful and versatile threads. Let’s take a look at how these two threads are similar, how they are different, and when I recommend using each one.
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For years, I’ve touted nothing but Aurifil 50 wt thread for piecing and quilting, but I’ve recently begun using and recommending 40 wt, too. This comes with some obvious questions: which one is better? When should I use one vs the other? Do I really need both? I’m here to answer all those questions today, but first, a bit of back story:
When I first began quilting, I learned about Aurifil thread on a quilting podcast. The speaker praised it as “the best thread for everything,” and, being a newbie quilter who was excited to learn about all the tools and notions of my new hobby, I immediately saved up and bought my first box of small 50 wt spools. I used it for my very first “proper” quilt with designer fabric and free motion quilting, and I was definitely impressed by how well it stitched and how bright and shiny the colors were on the spools and my quilt. Shortly thereafter, I had the opportunity to work with Aurifil for the first time on a charity project, and I’ve been a dedicated fan ever since.
Over the years, I’ve had more and more opportunities to collaborate with Aurifil, one of the more recent including becoming an Aurifilosopher (Aurifil thread educator; click here to book a virtual Aurifilosophy lecture for your guild!). Thought this part of our relationship, I’ve had the opportunity to learn about and use the full product line of Aurifil thread (so much wow!). As the free motion quilting educator collaborating on the Color Builders 2021 project, I’m deep diving with 40 wt in a way I haven’t done before, and I’m LOVING it! So, let’s get into the nitty gritty, shall we?
What is the difference between Aurifil 40 wt and Aurifil 50 wt threads?
First of all, both threads are two ply (two stranded), high quality cotton threads. Both are available in 270 colors. Both are incredible for a range of tasks including: machine quilting, machine appliqué, embroidery, binding, and using in your bobbin. As you may have already guessed, the only key difference is the weight of thread and what that means.
When discussing weight of thread, the smaller the number, the thicker the thread. The weight is determined by how many meters of thread it takes for a skein to weigh one kilogram. In this case, the 40 wt thread is slightly thicker (heavier) than the 50 wt thread.
Note bene: you can tell at a glance which weight you’re grabbing from your collection: 40 wt is always on a green spool while 50 wt is always on an orange one.
When should I use 40 wt thread vs 50 wt thread?
The extra weight of the 40 wt thread makes it ideal for projects where you want a bit of “pop,” but you still want to avoid your stitches becoming too bulky or having extra tension challenges (I find heavier weights of thread can get a bit persnickety, but 40 and 50 wts are both easy to balance in my experience). Using 40 wt thread for FMQ, thread painting, embroidery, or appliqué is going to add just a little extra dimension, richness, and texture to your quilt. I also love Aurifil 40 wt thread when quilting a looser, all over quilting plan. The bit of extra stitch definition subtly takes the whole project to the next level.
Meanwhile, I recommend 50 wt for piecing, English paper piecing, foundation paper piecing, and hand appliqué.
(yes, if you’re making the Endangered Species BOM with me, I recommend getting a neutral spool, 2600 Dove Gray perhaps, of 50 wt thread to piece with)
Do I really need both?
The pragmatic side of me wants to say, “You really could get away with just the 50 wt— it’s so versatile!” But, as I’m quilting more with the 40 wt, I’m totally enamored the added definition it adds. I’ve also mixed multiple thread weights on one project a couple of times, and the effect is amazing! The areas stitched with heavier thread “pop” even more, and the areas stitched with finer thread melt into the background.
Above, I quilted the entire navy background with 50 wt matching thread. It makes incredible texture, and the fineness of the thread kept the quilt from getting stiff. For “Expecto patronum,” however, I layered several colors of 40 wt thread to create an incredible POP.
If I’m building a rainbow collection of one or the other, am I going to regret not having the other one right away?
Not at all! Both of these threads are incredibly versatile, and you’ll enjoy using what you have. If you’re building a collection of 40 wt thread (such as with the Aurifil Color Builders 2021 program), I do recommend purchasing a spool of 50 wt thread to piece with since it a bit finer. I use Aurifil 2600, Dove Gray.
Do you have more resources about these threads?
You bet I do, Rockstar! Here you go:
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