welding SS tubing question

admin

Hello i am new to this site. at the current moment at my shop i am doing a project where i am TIG welding SS tube. the tube is 304 stanless .049 thickness. the machine is a miller syncro wave 180SD. and i have 100% pure argon. i have welded alot of steel and alot of aluminum, but minimal stanless steel now my problem is that the weld is not coming out nice. it is a grey color and not nice.should i be back gassing the tube. what is needed to produce a uncontaminated weld that looks right.mostly a gold and blue color.i am hoping to weld more tomorrow. If you guys could help me that would be great. thank you very much
Reply:it sounds like you have to much heat or not enough gas coverage Try using a gas lens for more gas coverage as well as turning the gas up a bit and leave the gas on for atleast 5 seconds after you have stoped welding if that doesnt work move faster play around with turn the amps up and down because sometimes on thin i find it easy to turn it up a bit and try to out run the heat if its a small weld
Reply:You should be purging a tube that thin, and you are likely running too hot.
Reply:Originally Posted by Bozzzait sounds like you have to much heat or not enough gas coverage Try using a gas lens for more gas coverage as well as turning the gas up a bit and leave the gas on for atleast 5 seconds after you have stoped welding if that doesnt work move faster play around with turn the amps up and down because sometimes on thin i find it easy to turn it up a bit and try to out run the heat if its a small weld
Reply:ok thank you guys very much for the info. i am currently welding with a #7 cup. unfortuanitly there arent that many options for my tourch. But i do have a larger one that i will try. and the flow is at about 20 now
Reply:Originally Posted by morgan@GMSok thank you guys very much for the info. i am currently welding with a #7 cup. unfortuanitly there arent that many options for my tourch. But i do have a larger one that i will try. and the flow is at about 20 now
Reply:by code your generally required to back purge stainless steel. 0.049 is 18 ga and it will "sugar" (oxidize) on the backside just about 100% of the time if it isn't purged.  You didn't mention the size of the tubing.  But in a pinch you can fabricate a dam out of cardboard and tape. Argon is heavier than air so purge from the bottom up and don't be tempted to set the purge CFH real high in an attempt for it to evacuate faster it will just trap in oxygen.  IIRC you want to cycle about 1.5x the volume of the purge area before you start welding then set the purge real low like 5-15CFH.of course I wouldn't go to that much trouble for some makeshift garage type work.   Another trick is to have some one follow the weld with another torch that just has the argon turned on.
Reply:ok thank you guys very much. i got the bigger cup yesterday and it was storming so bad it knocked the power out haha just my luck. so i will give it a try today with the back gas. and what is the best way to set this up.  the tube diameter is 3.5 inches and not a small project it is a full exhaust syestem for a 2009 nissan GTR.  Thank you guys all very much you have all been a great help. i should have joined this site a long time ago
Reply:Originally Posted by morgan@GMSok thank you guys very much. i got the bigger cup yesterday and it was storming so bad it knocked the power out haha just my luck. so i will give it a try today with the back gas. and what is the best way to set this up.  the tube diameter is 3.5 inches and not a small project it is a full exhaust syestem for a 2009 nissan GTR.  Thank you guys all very much you have all been a great help. i should have joined this site a long time ago
Reply:ok thanks again i will be getting set up to back gas tonight and ill be giving it a try tonight.
Reply:is it strong enough if i fusion weld the exhust. or do i need ro use filler rod
Reply:Use rodCigweld Transmig 265seBoc 140amp StickBoss 200amp AC/DC TIGLincoln Electric Invertec V260-S