Cup size question

[Mark_k]

Welding some 16ga mild steel. Looking at going with a 12 cup with .40 tungsten and .035 filler. Currently using 1/16 tungsten with .035 filler with a BBW cup. Would the 12 be over kill?

[Bushytails]

I'm a 42, somewhere between A and B... Oh, wait, that's not what you're asking about!

My understanding is you only need large cups for stainless and titanium, and you'd do fine with a #4 cup on mild steel with a .040 tungsten, so a #12 would indeed by way overkill. Does your application require abnormally long stickout?

[Mark_k]

It’s a receiver for a MP5. I don’t need a lot of stick out for it.

[ryanjones2150]

I love the BBW cup, but it is overkill for a lot of things. But you’ll certainly get adequate shielding for your kit gun.

As far as the tungsten goes, I prefer to dress down a larger tungsten to do smaller stuff. 1/16 is already pretty thin, imagine dressing the tip on that .040. But whatever you decide to do, be careful and use a small length of tungsten when you dress it down so it’s a little more rigid and less likely to send to 50 shards of tungsten into your eye ball.

[Ltbadd]

You're going to be pushing the limit of an .040" tungsten, 1/16" is good and 3/32 works too. Save the #12 for when you have an application that requires it.

I weld a fair amount of stainless using a gas lens and a #8 cup, but I do have a #12 to throw in if I need it. Even at 50 amps I still keep the 3/32" tungsten in, no need to change size unless I'm welding below 30 or in a tight spot and need the room.