Having just published a post, I was just reviewing my projects to-do list...
After many hours of on-line searching I've found that whilst it's possible to build an arc welder it's neither easy nor cheap!
to buy one from a shop costs about £100.
to buy one from a car boot sale costs about £10.
I've bought one at a car boot sale.
I plan to convert this to also be useful as a TIG welder as well. (though this won't be useful for aluminium unless I can design a HF start circuit).