Difference between machine hand washing and hand hand washing?

[orangeandemons]

I bought a very expensive cashmere cardi from Pure Collection. It said on it, do not machine wash..

I did machine wash it, on the delicate cycle on cold. Am sure it shrank. Washed it again. Am now convinced it shrank. Now, I have a degree in textiles, and know a lot about textile science, and to my mind there is no difference between the two. So why has it shrunk?

I don't know. I wash all my cashmere in the machine and it has never shrunk.

Same here, all my cashmere has been washed in the machine

The pain and heat will cause it to shrink.

Ahem ... Spin

The heat will cause it to shrink, but not the spin. It was on the lowest possible spin cycle, and was washed on cold

But cold on a machine is 30 degrees . Cold hand wash is in cold tap water . What exactly did the label say.? In my experience you can always push materials up a level ..I.e If it says wash at 40 it will probably survive 60 .

My machine has a 30 degree wash and a cold wash. But even 30 degrees is hand hot.

The label says: hand wash inside out. Dry flat, do not machine wash. It's the do not machine wash that gets me, it means cock all these days with modern washers, and who has the time to hand wash stuff.

Cold wash with no agitation or very very low agitation is equivalent to a hand wash

My machine has a cold setting as well as a 30 setting so I use cold hand wash setting to wash cashmere and wool and have had no probs. Spinning and agitation can matt the fibres and cause shrinkage, so maybe your machine is a bit too violent ?

Did you wash it with heavier fabrics too? That might cause more agitation? Could be to do with material itself, can imagine a looser or thinner weave would be more susceptible to matting and shrinkage.

I washed it on its own, with a very low agitation. Much lower than handwringing it.

I know heat can physically alter the scales on the fibres to make them lock up, but not sure how spinning can do this. I can see it might weaken them, but not matt them up

That's how you make felt, by agitating wool.

I respin all my cashmere on the 1200 cycle after it has finished the cold wool wash. It sounds like the jumper is at fault not the washing method.

I know felting is about agitation, BUT it needs heat to make the felt. Agitation alone shouldn't have any major effect.