I have used corrugated ribbing in several of my new designs, including the San Donato hat & mitts and the Murano hat. I love the stripey edging it produces. It does, however, have its own characteristics which are very different from ‘normal’ (e.g. k1,p1) ribbing. In particular:
- it does not contract and ‘cling’ like normal ribbing
- it is firmer and much less elastic than normal ribbing, due to the stranding of yarns behind the work
- it has a tendency to curl
On my travels around the internet I found a few interesting blogs and tutorials giving various tips and tricks for corrugated ribbing.
On the topic of a curling lower edge, in this article by Maggie’s Rags there is some helpful commentary about different types of cast-on to reduce curling. In this article by TECHknitting a different approach is proposed: working several stockinette rows for a deliberately rolled edge before starting the two-colour ribbing, or starting with some rows of single-colour ribbing. Elsewhere I read that the method recommended by Meg Swansen is the German Twisted cast-on. I tried this method and indeed found that it did not curl, therefore I tend to use German Twisted cast-on for corrugated ribbing (see my blog post on German Twisted and Channel Island cast-on methods).
I also experimented with different methods of working the two colour rib whilst avoiding the need to purl continental style with the yarn in my left hand (whilst I am able to do this, I find it more fiddly and slow than English style, which is my usual method). Below is an example of two of the ways I tried:
a) On the left I used ‘multiple pass’ knitting where I worked all the knit stitches in the round using the lighter (main) colour, slipping the purl stitches. At the end of the round, I turned and worked back the other way with the darker (contrast) colour, slipping all the stitches I had worked in the main colour and knitting the alternate stitches in the contrast colour. This was quite a quick method involving no purling at all, although when working with the contrast colour it is necessary to bring the yarn forward when slipping each intervening stitch.
b) On the right, I worked with both yarns at the same time with the main colour (knit stitches) in my left hand and the contrast colour (purl stitches) in my right hand. This way I only had to purl English style, which I find much faster.
There is a noticeable difference in the two techniques – in method a) the (purled) contrast colour is much more dominant and the ribbing appears less elongated – possibly also due to my gauge being slightly tighter and more consistent between the two colours. In method b) the columns of knit stitches are dominant – this may due to that yarn being carried in my left hand resulting in gauge differences and also colour-dominance (see my post about colour dominance in stranded colourwork).
Finally, in the example above, you can see that the purl stitches in first row of two-colour ribbing show a small ‘blip’ of the lighter coloured yarn, due to these purl stitches being worked immediately after a row of stitches in the lighter colour. Whilst this is a matter of personal preference rather than a problem, this can be prevented by working all the stitches as knit stitches in the first two-colour row, reverting to k1, p1 thereafter.