When you are learning how to tig weld, padding beads on plate and alternating between aluminum and carbon steel can really speed up the learning curve and is a better way to learn how to tig weld than welding only one type of metal....Read the full article on better TIG practice here
The 2 main TIG welding rods used for mild steel are ER70S2 & ER70S6.
Either one will do fine for TIG welding practice but a lot of folks prefer ER70S6.
Diameter of the rod used is also important.
The weld joints shown in the video above could be welded with .045", 1/16", or 3/32" filler rod.
I chose 1/16" diameter as my preference and I think a lot of experienced tig welders would agree with that choice.
But there are no hard and fast rules for selecting a rod diameter unless you are working off a welding procedure that specifies rod diameter.
This video on TIG welding aluminum has lots of great tips along with clear arc shots and plain talk explanations of how to tig weld aluminum.
If you searched for "how to tig weld" I hope you get tons of value out of my videos on this page.
There are hundreds of How to TIG Weld videos here at weldingtipsandtricks.com so if you need something more basic or advanced you can find that at my main TIG Welding page
If you are new to TIG welding and don't have a TIG welding machine yet, I have a recommendation for you for your first TIG welder.
Its the PrimeWeld TIG225x
Not only is it a very capable TIG welding machine, but it is also very affordable and Primeweld is well know for their exceptional customer support.