How to make 220v outlet?

Power delivered (ignoring those nasty losses) is volts times amps. If you need 110 watts in the welder, its 110V x 1A, or 220V x 0.5A. For the same power delivered your 220v wiring only has to carry 1/2 the current that 110v wiring does. For the same gauge wire you can provide twice the "power" from a 220 v circuit that you can from a 110v circuit. 220v wiring allows lighter gauge and/or longer wire and/or more power. This is a very simple explaination, and I'm sure to get a flamed for it, but that's the gist of it.

If you really don't understand, please call an electrician to do this.

Since you're on aol, I'll assume you're in the US and are talking about a residence. In the US and Canada, there is usually 240V present at the service box in stand-alone homes. There are two 120V 60Hz circuits (center-tapped 240V) and a neutral. Heavy appliances like electric dryers and electric water heaters are wired in to the 240V or connected with a big plug in the case of the dryer. Apartments and commercial buildings often have 208 rather than 240 because they are fed from 3-phase. (sqrt(3)*120 = 208).
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