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Question
Ernie I was hoping you could help me I'm a pipe welder i have passed 6g tests on carbon pipe stick and tig now I'm trying to master stainless I do not use the dip teqhnique on my root I prefer the lay wire technique, on carbon pipe I keep a tight 1/8 gap just so my wire doesnt fall through I have been trying this method on stainless but I have been having problems. Do you think I should try something diffrent or just keep practicing ,also do you have any suggestions for setting my heat before doing a open butt because most of the time its a machine I havent used before and your not allowed to run a practice coupon.A NY HELP YOU CAN GIVE ME WOULD BE VERY MUCH APPRECIATED. THANK YOU... Also the pipe test most common for me is 2'' sch40 sometimes stainless pipe with stainless wire sometimes carbon pipe with 309 filler wire..

Answer
The rules of stainless steel are different that for carbon steel.
Stainless melts at a lower temperature, and has greater shrinkage from cooling.
Dip technique always worked better for me, as it allows you to add more metal as you go.

Amperage rules are simple. Stainless TIG welds at 1/3 (33%) less amps than steel.

When welding out your pipe quarters, always weld opposing sides in sequence so you don't distort in one direction too much.

When welding carbon steel with 309L keep your heat low.
You don't want to dissolve the stainless into the steel too much or you will get horrible cracking problems.
Treat it like brazing, and just clad the stainless onto the surface of the steel.
This also works when dealing with Inconels or Duplex Stainless steels.  

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Ernie Leimkuhler

Expertise

Questions about Oxy-Acetylene welding/cutting, MIG, TIG, Flux-core, Stick welding, brazing and soldering, bike frames, air frames, motorcycle frames, structural welding. Also questions about Welding Certifications and Inspections. All questions about fabrication of metals (stainless steel, steel , aluminum, brass, bronze, copper). Basic questions about underwater welding. TIG is my strongest subject.

Experience

Extensive background in most welding fields. 18 years fabrication of metal theatre scenery, 16 years structural steel, 2 years pipe welding, 9 years as a Welding Instructor at South Seattle Community College, and 5.5 years as a Welding Instructor at the Divers Institute of Technology. 16 years Industrial Welding Consultant for fabrication shops in the greater Seattle Area. 11 years Architectural Metal Fabrication. 8 years in Film/TV; SPFX/construction/set-deco/props/. 33 years Blacksmithing and Knifemaking. Currently a Field Welding Inspector for Otto Rosenau and Associates.

Organizations
American Welding Society - Certified Welding Inspector Washington Assoc of Building Officials (WABO) - Special Inspector - Structural and Reinforcing Steel.

Publications
Do a search on google groups for "Ernie Leimkuhler" in the rec.crafts.metalworking and sci.engr.joining.welding groups. http://www.stagesmith.com/ http://www.metalwebnews.com/ Blacksmith's Gazzette - Anvil Making

Education/Credentials
BA Theatre Technology - Purdue University.

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