[davidimurray]

I've got one of those welders in your first ebay link. Bought it for £120 a few years ago as a bit of a risk. It has been brilliant - I've welded my whole chassis by TIG and uprights , diff mounts etc (i.e. thicker bits) with the arc function because I'm tight and didn't want to buy more gas (and I love arc welding!)

I welded my sump with it. When it comes to thin material it can be quite tricky to use as you find you have to set the current quite low to start with and take a long time to make the initial weld pool before moving on to the seam. Alternative is set current higher and go like the wind. If I was to weld more thin material, I would get a TIG welder with a pedal to give you more control.