Following on from my last post: Slipper Felting - Part 1, this is where we go all-out and talk about throwing your knitted slippers into the wash.
Firstly, all the samples here were felted in a front loading washing machine; in fact all the felted items I make are felted this way, because it is all I have. This does not stop you from using a top loader if that's what you have, in fact felting is much easier in a top loader as you can whip your item out almost whenever you want. The types of programs and lengths that I give will be slightly different though. You can also felt items by hand, it takes longer but you do have more control over the finished item. This method comes in particularly handy if you have felted something in the washer and it is almost the size you need it, but not quite, or if for some reason it has not felted evenly. If you don't want to take a chance on it becoming too small if you put it though a whole wash again you can finish by hand.
I come across plenty of people, mainly here in the UK, that would not felt anything because they have a front loading washing machine. I think opinion is that you really need a top loader to be successful. This is certainly not the case and although you perhaps don't have the control you would like, you can still produce felted items with great success.
There are so many variables when felting something it can seem complicated but it's really not. Mostly you can just take a chance and see how things go but it does help to have a little background knowledge to better your chances of getting exactly what you wanted.
To put your item in a lingerie bag or not.I know that a lot of people use lingerie bags to put their item into and felt in that. This is, I think, mainly to keep any fluff that comes off of during the felting process out of the machine. To be honest I have never used one and never had a problem but that is only my experience and if you have an expensive machine and don't want to take a chance, using one can't hurt.
Detergent.I use ordinary laundry detergent to felt all my items. If I am hand washing a delicate hand knit I only use a wool wash but I have always been of the opinion that as I want my item to shrink and be hard wearing, not needing it to be particularly soft so, to me, using an expensive wool soap has no advantage.
Temperature and Length of wash.This really is the crux of the matter isn't it? No matter what machine you have, whether or not you use a bag to put the item in and what detergent you use, it all finally comes down to what temperature and for how long to get the item come out how you want.
Unfortunately, there really is no easy answer. I would love to say, 'oh, just do this and all will be perfect' but in all honesty I can't.
The following knitted samples were all made in Cascade 220 held double, at the gauge I use for my slipper patterns except D which was the tighter gauge sample I used in part 1.
I washed each slightly differently. Each came out a slightly different size. Again, I have worked out a percentage decrease for each one so you can see exactly the difference it made. It all seems a bit technical but I wanted to be as accurate as possible so you could see what difference a wash can make. I have left out sample D as it is not relevant here.
Sample A = washed at 50 deg C / 122 deg F for 1 hour with towels
Sample B = Same wash as A but with denims not towels
Sample C = washed at 40 deg C / 100 deg F for just over 2 hours with clothes
Sample E = washed at 30 deg C / 86 deg F with towels
The following are the percentage decreases in size:
Sample A = -13% width x -26% height
Sample B = -11% width x -20% height
Sample C = - 17% width x -27% height
Sample E = 0% width x -10% height
So as you can see, all exactly the same in all respects to begin with, so different after a wash. Even changing what you use to agitate your item with changes your outcome. In my opinion, felting with the towels which 'foam' up the washing water more is why that particular sample felted more.
For my patterns, using the recommended yarn and sizing information, I use the wash from sample A - 50 deg C / 122 deg F for 1 hour.
Too much information? Probably.... maybe, but I hope that this has given you something to think about when embarking on a felting project and perhaps taken a bit of the mystery surrounding it away. The good news is that, with the exception of sample E, overallthese figures will not make a huge difference to what exact size a small item such as a pair of slippers comes out. If your slippers are a little loose, felt a little more (see part 1), if they are a little small, put them on while still damp and wear them around for a while, they will stretch to the size of your feet.
Mostly, just have fun with your felting and experiment.