The answer is to not touch the stone with your fingers.
FWIW, many of us have bled on our stones the same way, you'll learn to avoid this soon enough.
Fudoushin Bujinkan Dojo: http://fudoushin.com/
Does anybody have any ideas on why I can sharpen my global chefs knife ok, but can't sharpen a friends mac chefs knife?
The mac has had a couple years of steel only maintenance so is probably pretty fatigued but I can barely get an edge on it but can on my global.
Fudoushin Bujinkan Dojo: http://fudoushin.com/
It's pretty thin compared to the global, and it does seem to be raising a burr well enough. I did improve the edge compared to what it was, it just is still relatively blunt compared to what I can do with my knives, although that's nothing compared to what some of you guys can do.
The Global will take almost any edge. That doesn't mean it can hold it.
Through my own personal experience of sharpening a few knives with years of steel abuse the edge basically felt... Buttery( for lack of a better word. slippery and rounded from Never having enough metal removed from the edge or behind it. It took me a lot of work on a very course stone to remove the old dead steel. it then felt right and would take a nice edge.
I'm by no means close to a fantastic sharpener, so take it with a grain of salt, but I had a similar experience with my mom's no name knives (getting in any sharpening practice I can get). Even if it was a crappy knife, it should take a reasonable edge still. I couldn't get it to do anything on my 1k even though I could get my personal knives rather sharp with just 1k touch-ups. So at someone's suggestion, I ended up buying a coarser stone which made the difference. What stones are you using Farrant?