Monday, 4 August 2014

What happens to wool samples in the lab? Part 2

Once the samples have been washed, they are dried and ground. Grinding hair samples is tricky, as they're very elastic. To do this, we use a machine called a ball mill.
Loading wool into a ball mill cartridge
The wool fibres, which are 5-20cm long in the fleece, are cut into ~1cm lengths. Then they are loaded into the steel cartridge with a grinding ball. The machine shakes the cartridge so that the ball crushes the other contents. Note that I'm handing the samples with tweezers: this is partly to make sure they're kept as clean as possible, but mostly because the fibres are very static and stick to my gloves...

Milled wool 
And here's the result after a minute or so: wool powder. Like the whole fibres, this is usually static as anything, so it needs really careful handling to stop it jumping about!

Next: weighing into unbelievably tiny capsules in Part 3.