Which thread is the best for piecing quilt blocks? If you engage with the quiltsagram (the quilting community on Instagram), you probably hear A LOT about Aurifil thread. I mean, people go CRAZY over this stuff! It's like it's THE ONLY decent thread available. I've always found it to be a bit expensive for my tastes, but so many quilters seem to love it that I thought it was time to see what all the fuss was about. So here it is, a head-to-head test.
The Threads
In general, when piecing, there are three criteria you want to meet: (1) always use cotton thread, (2) use as thin a thread as you can reasonably acquire, and (3) use thread from a quality manufacturer. (And yes, this matters. Cheap thread is extremely linty and annoying to work with, breaking frequently. You can read more about why these three things are important here.)
For me, the thinnest cotton thread I can reasonably acquire from a quality manufacturer is 50 wt thread (yes, they make 60 wt and even 80 wt cotton threads, but those are expensive and difficult to get a hold of in the quantities I need for piecing). I've used many threads over the years (from the cheap stuff you can get at Walmart, to more specialty stuff) and the one that I've used most frequently and enjoyed is Wonderfil Konfetti Cotton 50 wt thread. It's certainly not cheap, but I can almost always get it on sale and it's always performed reliably for me. However, it is nowhere nearly as popular with quilters as other threads and I've always wondered why.
That's why I'm pitting my usual piecing thread, Wonderfil Konfetti Cotton, vs. Aurifil 50 wt cotton thread to see how each holds up. Here are the threads I tested:
1. Wonderfil Konfetti Cotton: 3 ply, 50 wt, double gassed, mercerized, long-staple Egyptian cotton.
2. Aurifil 50 wt: 2 ply, 50 wt, double gassed, mercerized Mako Egyptian cotton
The Experiment
I used both threads to sew some rail-fence blocks that I'll be using later this summer to make a guest book quilt for my sister-in-law's wedding. These blocks were strip pieced, and that made it the perfect test to compare both threads in a controlled way.
I sewed the top set of seams with Wonnderfil Konfetti, and the bottom set of seams with Aurifil 50 wt. Since I was strip piecing, it was easy to ensure that both threads were sewn at the same speed, for the same distance, and pressed exactly the same way using the same fabrics. All of that removed as much variability as possible so that any differences were solely the result of the difference in thread. I cleaned my sewing machine thoroughly before and after testing both threads.
The Hypothesis
Both threads come from quality manufacturers so I wasn't expecting to see much of a difference between the two. The only difference I thought I might see was a difference in the amount of lint build-up or a slight difference in how flat the seam laid, so those were primarily the things I was looking for
The Results
Straight out of the package, I noticed that the Aurifil thread felt slightly silkier than the Wonderfil thread. I had thought this might require some adjustments to my tensions, but both threads worked equally well in my machine. I had no issues achieving good tension or with thread breakage. (As expected; these are both good quality threads.)
Next, I looked at the amount of lint produced. Both threads produced about the same amount. Although surprisingly, most of the lint in my hook area (the parts around the bobbin) actually came from the fabric and not the thread. How do I know this, you ask? The lint was purple and I wasn't sewing with purple thread. This is a little-known fact: most of the lint that needs to be cleaned out of your sewing machine actually comes from the fabric you're sewing with, rather than the thread. (Again, true as long as you are using quality thread. I've seen some very nasty lint piles produced in very short amounts of time from lower-quality cotton threads!) Now, admittedly, I only sewed 21 width-of-fabric strips with each thread. Had I sewed a lot more, maybe larger differences would have become apparent. Regardless, I sewed long enough to observe lint build-up, and both threads performed roughly the same.
Finally, I look at the seam flatness. Both threads produced equally flat seams. Again, maybe there were some slight differences, but they were so minimal that it wasn't observable when 21 seams (quite a few!) were stacked on top of each other so this probably isn't going to make a difference in the long run.
So that's that: both of my hypotheses blown. However, I did notice a couple of unexpected differences.
First, I got a lot more thread on the bobbin when I used the Aurifil thread. I needed just over a full bobbin to sew my 21 strips with Wonderfil Konfetti, but I still had a significant amount left on the first bobbin after sewing my 21 strips with Aurifil. This is no doubt because Aurifil has one less strand (2 ply vs. Wonderfil's 3 ply), but I was surprised it made that much of a difference. Ultimately, that means less bobbin changing and less bobbin chicken which is no doubt a good thing.
Second, when I ran the price difference, I realized that Aurifil isn't actually more expensive like I thought.
Typically, I purchase Konfetti cotton directly from Wonderfil's website (usually whenever it goes on sale or when there is a coupon). I always purchase it by the cone rather than the spool because I go through a lot of thread. 1 cone of Wonderfil Konfetti Cotton thread costs $22.10 for a 2500 yd cone. That's $0.00884 per yard.
Conversely, Aurifil 50 wt thread cone prices can vary widely depending on who you're purchasing from. Online through the Fat Quarter Shop, a 6452. yd cone of 50 wt Aurifil thread will cost you $48.48 which is almost double the price. However, when you work out the price per yard, it's actually only $0.00751 per yard since the cones are so much bigger. That's slightly cheaper than my usual Wonderfil Konfetti and price was my main reason to stay away from Aurifil in the first place. It's also worth noting that other online distributors, such as Wawak, carry Aurifil cones for even less than that.
Now, if you sew more casually and don't want to buy huge cones of thread, the price per yard does change slightly. Wonderfil Konfetti large spools purchased full price from their website will run you $0.00878 per yard while large spools of Aurifil 50 wt purchased from the Fat Quarter Shop will run you $0.00948. So in that case, Wonderfil Konfetti is cheaper, but cones are always the better deal.
The Conclusion
So what's the point of all this? Well, I'll be switching to Aurifil bought by the cone just as soon as I use up all the Konfetti in my stash (that will be a while). As much as I hate jumping on the bandwagon, the data doesn't lie.
Performance-wise, the two threads behaved almost exactly the same. While I do like that I can get more thread on each bobbin with Aurifil, that doesn't justify a price increase for me. However, since it's cheaper than Wonderfil when bought by the cone, I'll happily switch. Every penny saved means more fabric budget for me!
If I wasn't buying by the cone, I would definitely stick with Wonderfil Konfetti. It's a quality thread with a more palatable price tag and your piercing will still turn out equally great.
Now I know there are a lot of other great threads out there that I didn't test, and I'm certainly not ready to say Aurifil is superior to all of them. I suspect they all (provided they're 50 wt or thinner) will behave very similarly to the Aurifil and Wonderfil threads tested here. Threads that would be equally acceptable to me include Gutermann Natural Cotton 50 wt, Sulky Cotton+Steel 50 wt, and Superior MasterPiece 50 wt thread. The only reason I don't use them is because they're harder for me to get reliably.
The threads I would definitely not use are bargain brand threads from a local box store (because they shred easily), or chunkier threads (30 wt, 40 wt, etc) from other quality suppliers because these are too chunky for a flat seam. It is more than worth the extra cost of buying a quality thread!
Are there other products you want me to test? Let me know in the comments. And make sure you're subscribed to my monthly newsletter to get quilting tips and tricks delivered to your inbox monthly!