Have you ever started a pattern and get a little way (or a long way) in before getting frustrated that it just isn’t sitting right?
Perhaps you’re trying to make a yarn bowl and it keeps flopping over side ways or you are wanting a nice slouch hat but it is sitting up like a chef hat. You picked yarn in the right weight, hook size is good, even did gauge if it asked for it so what is happening here?
I am guessing you didn’t use the yarn recommended by the designer. Now look I understand recommended yarn can be to expensive, unavailable in your part of the world, or discontinued or just not what you want to use. It is however important to substitute with a yarn with similar properties.
In the case of the yarn bowl if it is designed in a really structured 10ply acrylic yarn and you pick a 10ply silky acrylic with lots of drape then that bowl is never going to sit up for you.
Same with the hat if it is designed in a drapey 4ply light merino and you pick a creped heavier 4ply merino it’s not going to slouch how you envisioned it.
I am currently working on a design that uses very drapey cotton 4ply, stranded yarn. A couple of my testers wanted to use yarn that was very full bodied and it did not end well at all. The pattern is a square in the round and by round 7 both testers had “3D” squares that would just not sit flat.
I did a little experiment and was able to replicate the results.
Using a full bodied yarn I too got buckling. I made a little adjustment changing the corner to a 3 chain rather than 2 chain and it worked.. it worked, so well in fact I started to wonder if my pattern was wrong.
So I tested again using yarn with the correct drape properties. This time the yarn buckled and would not sit flat when I added the extra chain to the corners and laid as it should when done as the pattern stated… phew it wasn’t me lol.
As you can see it isn’t just the weight of the yarn that makes a yarn suitable. Of course for a lot of patterns you can easily just substitute out any DK for DK and run with it but if you are struggling with a yarn and a pattern it could be that the yarn structure isn’t compatible.
There are a couple of really good yarn substitution websites on Google. That let you search by brand, yarn properties like ply and fibre content.
The one I use the most is: https://yarnsub.com
I am not affiliated with yarn sub and I can’t guarantee all information is correct.