I have been on many forums and understand we all get tired of newbie questions. However after reading a lot here I don't have all the pieces of my question put together. I am a pretty good hobby welder. I have a solid Millermatic 250 mig. I am very,very comfortable welding .049-.250 mild steel (Build a bunch of racecars and trailer's and the like). However my new "Hobby" is Airboats. The most desirable riggings and cages are made out of stainless tubing with an O.D. between .625" and 1.0" and a wall thickness on .049-.090. I want to know what is the simplest way to make quality welds with my MIG. So I have some questions?1) Which gas 98/2% or 100% Argon?2) What size wire? Any particular brand? A supplier?3) Any changes to my machine? Rollers,Liners,Polarity?4) Push or drag generally?5) Settings,Speed,Volts and gas flow?Other guys do it with thier MIGs but I am not happy with thier results, I want mine to look awesome and I know y'all guys can head me in the right direction. A TIG would be cool but is not in the budget and would take forever. Lots of tacking and stuff. Thanks in advance. Todd
Reply:1) Neither, for short-circuit of SS you should be using tri-mix, 90% He 7.5% Ar 2.5% CO2 98/2 is good for spray transfer or heavier materials, but not thin short-circuit. 100% Ar is never used for MIG welding stainless.2) .023-.030 if it were me, but as far as brands go Everyone has their preferences.3) Nope, as long as the rollers and liner are the right diameter.4) Same as steel, the desired bead shape will dictate whether you push or pull.5) This will depend on your machine and wire, but your going to need a few more volts compared to MS wire. Gas flow can get bumped up 5cfh as well.Have we all gone mad?
Reply:skinny,While you may have done a "lot of reading", it would appear you're reading a lot of the "wrong stuff".Your questions about gas, wire, polarity, etc, etc would tell me that you've done absolutely NO prior research on welding stainless steel with the GMAW process.What you're proposing to do "build airboats with thin wall SS tubing" is not where an individual starts developing skill in mig welding SS. May I suggest you do a little more homework on building airboats in general. A google search or a search of the forum may prove beneficial. I think you'll find that thin wall SS tubing is NOT the first choice in airboat construction.You haven't even considered the need for purging to prevent sugaring on the backside of the welds.With what I'm reading, I'd say you've got about 1 chance in a million of getting a satisfactory result.In fact, based on the questions, you've got me a little scared about those "trailers" you put out on the road.Syncro 250 DX Dynasty 200 DXMM 251 w/30A SG XMT 304 w/714 Feeder & Optima PulserHH187Dialarc 250 AC/DCHypertherm PM 1250Smith, Harris, Victor O/ASmith and Thermco Gas MixersAccess to a full fab shop with CNC Plasma, Water Jet, etc.
Reply:Along the lines of what Sundown said. You really need to spend some time with welding and fabricating with stainless before you build the boat. Call it practice or simply making other projects.Stainless is not stain proof, its just less. It requires some planning to weld to ensure it's still stanless in the end.Assuming we are talking about 304 stainless, and typically 304L at that (extra low carbon)....304 works a bit backward. Its annealed by rapid cooling. It expands about twice as much as mild steel (watch your gaps), and when it cools, in contracts about 2x as well. Very easy to warp. .050 stainless will be a challenge with a MIG. 18 gauge stainless is .0500" thick.Heat doesn't move as easy through 304. That means your weld heat is concentrated. That also means you are not wasting as much power heating the rest of the metal. So knock 10% off the heat required (vs. steel). Oh, and remember that warping. That is now concentrated as well.Then there is the sensitivity to carbon. The sugaring that Sundown referred to is what happens when carbon reacts with molten chromium. Its a pretty fast process and these hard 'buggers' will form very easily on the back side of you welds. On the front side the weld will turn gray. You basically made whatever joint brittle and susceptible to corrosion.Stainless can be contaminated by high carbon steel.... like drill bits, grinding wheels, wire brushes etc.Grab the Fein or Walter Abrassives catalog. Probably the best collection of stainless finishing products.1) As for gas. If you are using small bottles traded in to your LWS, you will pretty much be limited to off the shelf tri-mix. Once you've got some time with tri-mix, you might want to re-visit 98/2. I have not tried this but you might want to read (with a gain of salt) Ed Craig's WeldReality website. Ed is not a fan of tri-mix and prefers, for thin stainless, prefers 98/2 Ar/Co2. As I mention earlier, I use TIG on thin stainless. You will have to either go with the tri-mix or experiment with the other mixes. Ed claims that 98/2 will put less heat into the weld but elsewhere he said it can also run at lower voltages. Ed's writing style is a bit scattered - he would benefit from an editor/proof reader.2) I assume you have an M25 gun on that. If so, you should be able to handle .023. There is no reason to go with bigger stuff for the sizes you mention.3) Rollers to match the .023 wire. When moving from .035 to .023 there is a thinner liner available. Not always needed, but if you are having feeding issues, consider the switch.4) Either push or pull will work. I would suspect that push is where you want to go (less penetration)5) If your 250 reacts like my 251, you want to use lower voltages than all the weld calculators out there. Rather than 19-20V, you want to try 17.5-18.5. With .023 wire speed should be roughly 240. The miller 250 series machines tend to have flat voltage curves. So when the current flow goes up, the machines don't loose as much volts. As a result you can run with a lower voltage and as a result of that, they tend to spatter less. For the MM251, miller recommends 18V/250IPM on tri-mix. On thicker steel, I find that I like about .5V more than the Miller chart on the door and about 20-30 more on the wire speed. Ultimately you will have to find your own settings.Con Fuse!Miller Dynasty 350Millermatic 350P-Spoolmatic 30AMiller Multimatic 200Hypertherm PowerMax 1000G3Miller Maxstar 200DX
Reply:Sundown, Why not try giving constructive replies instead of your usual criticism and belittlement ?Your posts sound like they are written by cantankerous person who is just mad at the world and is irritated that not everyone possesses the experience and knowledge with which you obviously possessed at birth.
Reply:A/C Guy,Possibly because I generally can tell the difference between a poster who's "blowing smoke" and one who really has done his homework.Even if you've never welded the first bead in stainless steel, why would you think you needed to change the polarity.When you go to weld thin mild steel, doesn't a smaller wire (.023) work better with the volts and WFS that the material demands. Why would stainless be different.I think if the OP does his homework, he'll find that there's a lot more aluminum used in airboat construction than there is SS. If he did a search here, he'd find a couple of airboats I suspect. If not, it was on millerwelds.com. Full writeup of a guy doing one.What gas should I use (98/2 or 100% Argon). I've NEVER seen a recognized source recommend straight argon for mig welding SS. If you check out Miller's GMAW Handbook they'll recommend the tri-mix. What's said in a "question" often tells more than you think.Syncro 250 DX Dynasty 200 DXMM 251 w/30A SG XMT 304 w/714 Feeder & Optima PulserHH187Dialarc 250 AC/DCHypertherm PM 1250Smith, Harris, Victor O/ASmith and Thermco Gas MixersAccess to a full fab shop with CNC Plasma, Water Jet, etc.
Reply:That still does not excuse poor manners and rudeness. Many times, your posts have a very strong attitude of elitism. I have worked with many journeymen that treat their helpers and apprentices the way that you typically reply to posts. The apprentices don't like it and they don't learn anything because of it. Try giving advice the way that you would like to have advice given to you.
Reply:Not this crap again...Im sick and tired of people always worrying about being nice and proper, I see no problem with being rude and blunt as long as you're right.Have we all gone mad?
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OL,If I was as "nice and polite" to some posters on this board as many of my mentors were to me, I WOULD HAVE BEEN BANNED FOR PROFANITY AND VERBAL ABUSE A LONG TIME AGO.But you know, I learned more from the brash knowlegable ones than I did from the nice uninformed ones.Syncro 250 DX Dynasty 200 DXMM 251 w/30A SG XMT 304 w/714 Feeder & Optima PulserHH187Dialarc 250 AC/DCHypertherm PM 1250Smith, Harris, Victor O/ASmith and Thermco Gas MixersAccess to a full fab shop with CNC Plasma, Water Jet, etc.
Reply:Well I kinda like Jays answers.......They break up the monotony of guys getting compliments for welds that will kill someone and make every good welder on here look bad for giving the wrong info........Hey if you suck you should know it so you have something to fix........It's not personal This is the internet and you can't take things personal........ Miller Dynasty 350Twenty Six HammersThree Crow BarsBig Rock
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Reply:If you don't think that's funny then you have NO since of humor........... Miller Dynasty 350Twenty Six HammersThree Crow BarsBig Rock
Reply:I appreciate all the replies guys. Even "Sundown" I am used to Internet bullies,the moniter hides all. I have done more than enough research and already talked to the biggest Airboat builders in the world about material. Aluminum is becoming more common but SS is still considered top of the line. Due to weight concerns thinwall is used for most of the structure with the exception on the actual engine stand which is usually .125 wall. I may have mistyped when I said a "lot" of reading. I have done some. I am starting this research to make sure my Machine is setup correctly so I can practise over the Summer and will be building a new boat in the fall (Gonna ride my current boat all summer). I would be willing to bet there are some very good self taught welders that have never read or studied welding alternative materials. I have been welding mild steel with MIG,Stick and even can really make a Brazing rod and torch come to life for over 20 years (I will be 34 in April). However reading all the posts here is very confusing. Even in this short subject there are some contradictions( One post says more heat and one says less). I would be willing to bet with some tri-mix,.023 wire and some sterile cutting and grinding wheels I can practise and learn to make high quality welds.
Reply:Originally Posted by skinny99 I would be willing to bet there are some very good self taught welders that have never read or studied welding alternative materials.
Reply:The problem with searching on this forum is you can't find the "right" answer, you find a lot of answers, none of which are correct. Or you find someone being rude such as the above posts and you don't want to read it or it makes you not want to ask for help because others will think you are stupid.Torchmate 2x2 CNC with Flashcut CNC controlsHypertherm Powermax45 Esab ET220i Razorweld 195 MigRazorweld 200ac/dc TigTormach 770, Tormach xstechRazorweld, Vipercut/Vipermig, SSC Foot Pedal Dealer
Reply:Originally Posted by GambleThe problem with searching on this forum is you can't find the "right" answer, you find a lot of answers, none of which are correct. Or you find someone being rude such as the above posts and you don't want to read it or it makes you not want to ask for help because others will think you are stupid.
Reply:I guess it just depends on how you read it.Torchmate 2x2 CNC with Flashcut CNC controlsHypertherm Powermax45 Esab ET220i Razorweld 195 MigRazorweld 200ac/dc TigTormach 770, Tormach xstechRazorweld, Vipercut/Vipermig, SSC Foot Pedal Dealer
Reply:Gamble,makes you not want to ask for help because others will think you're stupid...... Or just too lazy to do a little homework on your own and expect to be "spoon fed". In a "nice and polite manner" I may add.In my business (marine fabrication/repair) I work with "a lot" of thinwall SS tubing of varying sizes. I can't remember when the last time was that I picked up a mig gun to do "high quality work" on said tubing. If the OP had done a simple search on "airboats" he would have found two excellent/detailed posts. One was done with SS (tig) and one was done with Alum (tig).OP wants "quality welds" but insists on an inferior process to achieve them. A tig is not in the budget. Well then, maybe building your own "airboat" shouldn't be in the budget either. Last time I checked they wern't giving the platforms (the boat), engines, props, etc., etc. away either.About had it with the "politically correct new guys" who don't know jack about what they're talking about.I'll leave it at that before I show them what a real azzhole I can be.Syncro 250 DX Dynasty 200 DXMM 251 w/30A SG XMT 304 w/714 Feeder & Optima PulserHH187Dialarc 250 AC/DCHypertherm PM 1250Smith, Harris, Victor O/ASmith and Thermco Gas MixersAccess to a full fab shop with CNC Plasma, Water Jet, etc.
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on't leave I just popped some pop corn and poured a cocktail........Hahahahaha I like reading your replies..... Miller Dynasty 350Twenty Six HammersThree Crow BarsBig Rock
Reply:Originally Posted by skinny99I appreciate all the replies guys. Even "Sundown" I am used to Internet bullies,the moniter hides all. I have done more than enough research and already talked to the biggest Airboat builders in the world about material. Aluminum is becoming more common but SS is still considered top of the line. Due to weight concerns thinwall is used for most of the structure with the exception on the actual engine stand which is usually .125 wall. I may have mistyped when I said a "lot" of reading. I have done some. I am starting this research to make sure my Machine is setup correctly so I can practise over the Summer and will be building a new boat in the fall (Gonna ride my current boat all summer). I would be willing to bet there are some very good self taught welders that have never read or studied welding alternative materials. I have been welding mild steel with MIG,Stick and even can really make a Brazing rod and torch come to life for over 20 years (I will be 34 in April). However reading all the posts here is very confusing. Even in this short subject there are some contradictions( One post says more heat and one says less). I would be willing to bet with some tri-mix,.023 wire and some sterile cutting and grinding wheels I can practise and learn to make high quality welds.
