I want to know if I can use flux core wire in my Clarke Pr0 90 I'm going through Gas like there no tomorrow and I'm on disposable cylinders and at £10 a pop it's getting pricey!
You'd be much better off changing to using full size gas bottles, which is more of an 'upgrade', rather than using flux cored wire, which is a bit of a 'downgrade'!
B&Q I'd imagine would supply the highest quality of branded flux cored wire which would weld really well unlike the cheaper alternatives which might just spatter a bit. Or maybe not - ignore me a forum is no place for sarcasm.
Pro 90 is gas only I think - for best performance you'd want to swap the polarity (which you can't on that). But for thin stuff the polarity doesn't seem to make a great deal of difference so it could be worth a try to see how you get on. Depends what you are welding though - minimum thickness is higher with flux cored, so if hole blowing is a problem don't go there.
I'd be with Luke though in recommending a decent big bottle of Argon mix. Check out the gas price spreadsheet for some ideas.
Search for 'excel viewer' it's a free download from microshaft (yes, uncle bill does actually give some things away )
You will most probably find a rent-free gas supplier not too far from you too.