New to TIG.....

[HMW]

You got it just keep making puddles.......

[Dustyhaze75]

ya .............. weld steel with DC strait polarity (electrode negetive ) if you weld with DC reverse polarity (electrode positive) the tungsten may melt before the base metal because about 70 % of the heat is at the electrode, not at the work. penetration of the bace metal is poor when using DC reverse polarity (electrode positive). It is best used to weld very thin sheet metal(not aluminum or magnesium). shollow penetration then becomes an advantage. sharpen your tungsten like a pencil for steel and like a crayon for aluminum. ya it's normal for the tungsten to get red.

[safetydave]

Hi shop teacher, it's a different set-up to tig steel then tig aluminum ye s if you should dip or touch the tungsten to your metal it will contaminate your tung so DON'T DO THAT also yes it will get a cherry red when welding but try not to get it to hot or it will start to pop and then your in trouble,so try to keep your heat controled with the foot pedal, kind of like the gass pedaalon your car the more pedal the faster or hotter you will get so go slow when just starting out watch your puddle if it gets to big back off on the heat and add some more filler rod.I did some 1/2" cast iron the other day for a guy and I had my heat set at 175amps useing 1/8" tung and a roller switch on the head of the torch for on-off and it got hot but I just took my time with a couple of pass's and laid it in nice and thick,turned out great the guy was in shock at such a nice weld because some other shop did a crappy to say the least job who was the best in town acording to all the old school weldor's.
hope this helps you? if you need any more shoot me a line i'll see what else I can do for you, best of luck in the classroom.

[ShopTeacher]

A big thanks for all of your posts, your experience and knowledge is amazing to say the least.

SafetyDave: I know I'm a long way from ever welding cast iron but just for curiousity's sake, how do you do it?

[safetydave]

Shopteacher.
the parts i welded on were 1/2" thick brackets, so what i did was to grind off the RUST & DIRT to get to the bare metal then beveled the ends to create a nice deep groove (make sure they still match up) pre-heated them then spot tigged the corners (tacked in place) then using red tung (can't remember tech term for this) drawing a blank? and nickel filler rod 1/8" for what i was doing then just started to pre heat nice red glow then added filler on one side then switched to other side for a nice root pass around part then let cool for a few then went back over the other side from starting position takeing time to cool a few with each pass until i had three pass's on this part,root,fill,cap. The problem is that now i post stuff and give info on this site i forget to get some pics of the stuff i have done,so i'll hav to remeber the camera when i get a project. I'll try to remember anything else that i might have done to this part and get it to you and see if it casn help you with anything. untill then just keep practiceing on any thing you can.