The first video gives great tips for tig welding carbon steel, 4130 chromoly, stainless, aluminum, and even titanium.
The second video is about sanitary stainless steel welding.
The thing that really matter when tig welding different metal types is more than one single thing....but its also not a 100 things.
It is mostly metal prep, arc length, torch angle, argon shielding, and technique.
But lets start with metal preparation.
You need to be welding clean metal that is free from oxide layers, mill scale, paint, oil, coatings, or paint,.....clean bright metal.
Next you need good argon shielding.
The cups that come with your tig torch or welder are just ok for getting started.
But for getting the best results on a variety of metals, they fall short.
To get the best results, you need the right TIG cup for the application.
That does not mean every situation requires a different TIG cup.
There is a big difference in just getting by with something that works and having the best cup for the job.
Us welders get thrown into the deep end of the pond sometimes and it helps to have an arsenal of TIG cups and hardware to choose from to get the best possible result.
The Weldmonger® TIG pro Kit is like a Swiss army knife of TIG cup Kits with a cup for nearly every situation you might encounter.
The TIG pro kit has the most popular Furick cups along with large diameter gas lens cups and hardware.
One of the best things about a TIG kit like this is that you can be sure it all fits your TIG torch.
TIG cups are sized by 1/16" increments so a #4 is 4/16" or 1/4" inside diameter.
A #4 tig cup is useful for welding at extremely low amperage and low argon flow rates...for saving argon gas when the welding supply is closed and also for flash tack welding sheet metal.
A #5 is a favorite of a lot of tig welders for tig welding aluminum up to around .125" (3.2mm) thick
A #6 gas lens is a great all around cup for aluminum and so is a #7 or #8 when using a 1/8" tungsten.
A gas lens #6 cup will let you extend your tungsten much further than a standard collet body #6 cup. And sometimes you need to extend the tungsten to reach a weld.
If you weld stainless, 4130 chromoly, tool and die repair, or nickel alloys like inconel, a Jazzy 10 or Furick ceramic fupa 12 are great choices.