When you start thinking of using plasma cutter tig welder you must choose the material to weld because there are two different type of products being used in tig welding.
1)AC/DC products are capable of welding metals including aluminium
2)DC products can weld steel,stainless steel and alloys but not recommended for aluminium.
Welding as we know is to joint two materials mostly metals and steel.Tig welder are being used for years and as we know also there are many product which can be used for welding and cutting either by Miller,Hobart and Lincoln even Longevity Inc.
The most excelent plasma cutter tig welder product by Miller is 4 in 1 AC?DC for metals and aluminium.4 in 1 means this plasma cutter tig welder has 4 typical applications to use which are in automotive,motosports,4X4/Off Road and Sport aviation.
While in DC product which has 4 typical applications also, which are in fabrication,manufacturing,construction and maintenance plus repair works.In doing faster works you can use the Advance type for both AC and DC which is designed for easy set up and operating.
Even though some people afraid to use multipurpose product like plasma cutter tig welder but it seem does not make sense at all if you never try it even once.