Questions about tig welding pipe

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Hey guys I'm new to this forum and new to tig welding in general and I have a few questions.  I work in a brewery and I want to eventually be proficient at stainless sanitary welding.  I started on mild steel plate and now I have moved onto mild steel 2 1/2 pipe.   I have a million questions but I'll limit this thread to just a few ATM.  First, how much of a gap (or should I even have one) between the 2 ends to be welded?  The thickness is about the same as 16 gauge sheet metal.  Also how should the ends be prepared?  I have been putting a 35 degree angle on each piece and I've been keeping them pretty much flush but I've noticed I don't always get complete penetration.  Also, I know the guy who does a lot of work around here doesnt use filler wire on pipe this thin,  he just prepares the joints well and his work is gorgeous.  So how do other people do it?  I have been doing it both ways, just adding filler when it looks like the it might need it.Another question, when I get to the point where i am purging the pipe for the sanitary welds, do you have the purge running while you are welding, (particularly tacking)?  If so do you use a seperate tank to purge?  I'm just wondering how to keep a set, constant pressure to the torch if I am purging with the same tank. Sorry if these questions seem dumb, I'm pretty much learning as I go along.
Reply:Originally Posted by MotorbreathHey guys I'm new to this forum and new to tig welding in general and I have a few questions.  I work in a brewery and I want to eventually be proficient at stainless sanitary welding.  I started on mild steel plate and now I have moved onto mild steel 2 1/2 pipe.   I have a million questions but I'll limit this thread to just a few ATM.  First, how much of a gap (or should I even have one) between the 2 ends to be welded?  The thickness is about the same as 16 gauge sheet metal.  Also how should the ends be prepared?  I have been putting a 35 degree angle on each piece and I've been keeping them pretty much flush but I've noticed I don't always get complete penetration.  Also, I know the guy who does a lot of work around here doesnt use filler wire on pipe this thin,  he just prepares the joints well and his work is gorgeous.  So how do other people do it?  I have been doing it both ways, just adding filler when it looks like the it might need it.Another question, when I get to the point where i am purging the pipe for the sanitary welds, do you have the purge running while you are welding, (particularly tacking)?  If so do you use a seperate tank to purge?  I'm just wondering how to keep a set, constant pressure to the torch if I am purging with the same tank. Sorry if these questions seem dumb, I'm pretty much learning as I go along.
Reply:I can answer a purging question.  You can either T another regulator to the same tank, or just run two tanks/regulators.  I would just run two tanks.Gap, edge prep, travel speed and amperage are variables that you will change until you get full penetration.  Once you find your best settings, write it down.Dave J.Beware of false knowledge; it is more dangerous than ignorance. ~George Bernard Shaw~ Syncro 350Invertec v250-sThermal Arc 161 and 300MM210DialarcTried being normal once, didn't take....I think it was a Tuesday.
Reply:Thanks guys...ive got the general idea of what i need to do.  Probably going to invest in a dual flow meter soon.  Another question, what do you guys do to polish up your welds?  Our regular welder puts on some kind of acid and then hits it with a green scotchbrite pad.  Any idea on what acid he was using?  I forgot to ask.
Reply:I forgot to add I run it hot and fast in a tight circular motion.
Reply:Originally Posted by MotorbreathThanks guys...ive got the general idea of what i need to do.  Probably going to invest in a dual flow meter soon.  Another question, what do you guys do to polish up your welds?  Our regular welder puts on some kind of acid and then hits it with a green scotchbrite pad.  Any idea on what acid he was using?  I forgot to ask.
Reply:still doing search for 'austentacious welding'.  will report findings...
Reply:Originally Posted by fdcmiamistill doing search for 'austentacious welding'.  will report findings...
Reply:Originally Posted by MinnesotaDaveThat's a pretty funny typoI'm sure he means: Austenitic welding "Austenitic stainless steels have high ductility, low yield stress and relatively high ultimate tensile strength, when compare to a typical carbon steel." www.gowelding.com/met/austenitic.html
Reply:Originally Posted by Showdog75Skip the dual flowmeter and buy yourself the t that western makes and run two flowmeters off the same bottle.If one craps out you can still use the other.Not to mention dual meters are pricey.
Reply:Sorry, I jacked up that word pretty good!
Reply:If your new to tig welding and you want to run food products through the stainless you weld right now............Hire a good stainless welder to do your plumbing or you will be making people sick.......A lot to learn before you can safely weld stainless tube without  contamination  Miller Dynasty 350Twenty Six HammersThree Crow BarsBig Rock
Reply:Originally Posted by B_CIf your new to tig welding and you want to run food products through the stainless you weld right now............Hire a good stainless welder to do your plumbing or you will be making people sick.......A lot to learn before you can safely weld stainless tube without  contamination
Reply:Originally Posted by MotorbreathThank you captain obvious...exactly the reason I am trying to LEARN.  I've been brewing beer professionally for close to a decade, I don't need a lesson on sanitation .  As far as welding goes, it has merely been a hobby for the past few years but I want to be able to utilize this hobby when I go and start my own brewery.  I must say...being new to this forum and reading various threads...there is an quite a bit of negativity around here.  Tough place to come and learn .  But thank you to those of you who actually had something constructive to say.
Reply:I don't mind being taken down a peg...as long as I get some useful knowledge in the process.  Forgive me for being naive, I don't have anyone else I can ask these questions to.  I asked about the gap because I have seen a formula before about gap thickness relative to the thickness of the pipe being welded and I was curious if this was even applicable to thin-wall stainless.  It seems counter-productive to answer my question with a "go find someone else to weld it" response.  I don't think sanitary tig welding is beyond my comprehension, I just need some pointers.  Perhaps I'm barking up the wrong tree.  But I'm here anyway, and I'm going to be asking more naive questions in the future.  I don't have the time or money to go to a welding school.  I'm not trying to ruffle any feathers here, I'm just looking for some feedback from people with experience.
Reply:Well firstly you want to avoid gaps as then you are keyhole welding. You are not  arc or mig welding either. So zero gap is in order. The thicker the tube, the bigger the bevel as you are going to want that full penetration, or "Sanitary" joint that will catch no fluids or matter. And you know what that can lead to.If you are going to purge you certainly don't want gaps. Practice makes perfect. Good LuckWeld like a "WELDOR", not a wel-"DERR" MillerDynasty700DX,Dynasty350DX4ea,Dynasty200DX,Li  ncolnSW200-2ea.,MillerMatic350P,MillerMatic200w/spoolgun,MKCobraMig260,Lincoln SP-170T,PlasmaCam/Hypertherm1250,HFProTig2ea,MigMax1ea.
Reply:Originally Posted by shovelonYou are off to a bad start motorbreath. Just the fact that you are asking what kind of gap says alot. You did not list the equipment you use, grades of stainless, thicknesses, the like.You might not need a lesson on sanitation, but you do on sanitary welding. Gap, what a laugh. Bevel is more like it.
Reply:Originally Posted by MotorbreathI don't mind being taken down a peg...as long as I get some useful knowledge in the process.  Forgive me for being naive, I don't have anyone else I can ask these questions to.  I asked about the gap because I have seen a formula before about gap thickness relative to the thickness of the pipe being welded and I was curious if this was even applicable to thin-wall stainless.  It seems counter-productive to answer my question with a "go find someone else to weld it" response.  I don't think sanitary tig welding is beyond my comprehension, I just need some pointers.  Perhaps I'm barking up the wrong tree.  But I'm here anyway, and I'm going to be asking more naive questions in the future.  I don't have the time or money to go to a welding school.  I'm not trying to ruffle any feathers here, I'm just looking for some feedback from people with experience.
Reply:Originally Posted by Drf255  I can't imagine ruining a batch that size.
Reply:Originally Posted by MotorbreathI must say...being new to this forum and reading various threads...there is an quite a bit of negativity around here.  Tough place to come and learn :
Reply:Originally Posted by FODFAI agree, I actually think most people on the forum must be women with all the bitchin that goes onCheers Andrew
Reply:Was a hard start Motorbreath haha, i can't help you on any questions you ask about SS TIG, but im the same kind of people as you are, keeping asking basic questions and being honnest by saying that you are new and want to learn!If you were working in a shop, being pissed off to someone can give you trouble if you need to ask questions in the future, but here i don't really mind!If i can give you some advice, im into steel and stainless fabrication, sometimes when i really want to learn something correctly and no one in my shop can answer me correctly, i can't stay asking myself ''how to do it'' and after my day shift i go with my car to others shop with a smile and talking friendly if someone can take couple minutes showing me stuff, i did it when i want to learn how to bend sheet metal, how to layout circular raillings, normally peoples are really friendly!find a place near you that work in what you want to learn,and ask the forman ''hey do you have a good TIG welder that can show me stuff ??''Calculator > Bevel Square
Reply:This may help, here is the playlist link for Tig Time with Mr Tig. http://www.youtube.com/playlist?list=PLC6255E98E8E0A36CEpisode 7 and 11 are on TIG stainless and show the difference on the backside of what happens with purging vs no purging.  He has a slow presentation style, so be patient.Dave J.Beware of false knowledge; it is more dangerous than ignorance. ~George Bernard Shaw~ Syncro 350Invertec v250-sThermal Arc 161 and 300MM210DialarcTried being normal once, didn't take....I think it was a Tuesday.
Reply:Originally Posted by usmcruzYou wanna see a grown man cry!   I had to dump a batch once, and it gave me PTSD.
Reply:Don't worry about the negative comments. Some tend to forget how they started welding and the path to being better and that is by asking alot of questions. Here are my thoughts for your question. For this type of welding it is best to have no gap at all. if you are having problems with penetration it looks like it might be your travel speed / welder settings.The end shape of your tungsten can also be a factor. Pointy tip = deeper weldRounded = surface weldI suggest you take 2 plates of the same thickness as the pipe you are welding. Stick them together and tweak your settings until you get the results you want.hope this helps . good luck..Patrick SylvestreWelding Formanwww.learningtoweld.comWelcome Patrick. (PaSyl33) Nice first post.Do the goods from your online store ship from Atlanta, Georgia?  You show your location as Canada.Last edited by shovelon; 07-20-2012 at 10:14 PM.Weld like a "WELDOR", not a wel-"DERR" MillerDynasty700DX,Dynasty350DX4ea,Dynasty200DX,Li  ncolnSW200-2ea.,MillerMatic350P,MillerMatic200w/spoolgun,MKCobraMig260,Lincoln SP-170T,PlasmaCam/Hypertherm1250,HFProTig2ea,MigMax1ea.
Reply:well I started working for a contractor at the Anheuser Busch brewery here in Houston, Texas. Been there for 3 days now. Im not welding, working on the pipefitting side of things but what I have seen is on the Smaller diameter pipe they are fusion welding and on the Larger diameter pipe They are using filler. From what I've seen the Larger diameter stuff tends to be heavier wall schedule 10 if im not mistaken and I believe the smaller stuff is schedule 5.There are a lot of variables though. I've seen some use gaps and some not want gaps and they all want different kind of bevels. Aside from the thickness and diameter of the pipe there are also different grades of stainless we are working with. So in short I guess you have to be experienced enough to adjust to whats thrown at you I guess. I went to school for Pipe welding and I am learning a lot watching these guys.Last edited by pokerguy; 07-20-2012 at 10:38 PM.