Suggestions wanted - GMAW .065 wall tubing consumables / processes

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Hey All,As many of you know, I mainly work with regular ole' HR steel, SMAW and GMAW.  There just isn't much call for exotic work in my area.  That said, an unusual job request came up today.This will be an outdoors, dead-of-winter job.  The majority of it involves fillet welding 304 stainless, 1" square tubing x .065" wall, pieces to each other.  It is in-place welding, out of position - either half of the welds will be flat and half overhead, or all will be vertical.  There will be about 1,000 weld beads required, each one an inch long.  I *think* I can set up enough blinds to keep the wind at bay and use GMAW.  I sure don't have enough time to even attempt this with GTAW, and I've never used SMAW for stainless this thin, out of position.Available equipment on the jobsite will be a TB 302 engine drive, XMT-304 (no power available - would have to run off the TB), and Suitcase 12RC.  And a torpedo heater to thaw me out every now and then.What I'd like are real-world suggestions on electrode type and size, and gas choice.  This is a little outside of the material thicknesses and types that I work with every day.  Welds need to look good with a minimum of cleanup, but this isn't food grade.Any help is appreciated, and thanks in advance.
Reply:I've done a small amount of Stainless running .023 wire using my mig mostly for small misc projects. I'd think you should be able to do this with the 12 RC running directly from the TB. I don't see a need to run off the XMT, but you could if that's the way you prefer.You'd probably need to get a set of .023 drive rollers for the feeder, and a bottle of trimix set up for what ever stainless you are working on along with matching filler. Since this is thin stainless, I'd opt for .023 wire over .030 wire simply because A) I have a full size roll of 308/316 SS wire, and B) to keep the total heat input down. Keep in mind Stainless mig will not have the same look tig will..No government ever voluntarily reduces itself in size. Government programs, once launched, never disappear. Actually, a government bureau is the nearest thing to eternal life we'll ever see on this earth! Ronald Reagan
Reply:Originally Posted by DSWI've done a small amount of Stainless running .023 wire using my mig mostly for small misc projects. I'd think you should be able to do this with the 12 RC running directly from the TB. I don't see a need to run off the XMT, but you could if that's the way you prefer.You'd probably need to get a set of .023 drive rollers for the feeder, and a bottle of trimix set up for what ever stainless you are working on along with matching filler. Since this is thin stainless, I'd opt for .023 wire over .030 wire simply because A) I have a full size roll of 308/316 SS wire, and B) to keep the total heat input down. Keep in mind Stainless mig will not have the same look tig will.
Reply:You probably may need to look at a new liner for the gun if you have an .045 liner in the gun as well as tips ( forgot those the 1st time). Small wire doesn't always feed well in larger liners without bunching up and then suddenly jumping forward, making feeds erratic.As far as gas and filler, I'll leave the recommendations of that to those who do stainless regularly..No government ever voluntarily reduces itself in size. Government programs, once launched, never disappear. Actually, a government bureau is the nearest thing to eternal life we'll ever see on this earth! Ronald Reagan
Reply:Ha ha, don't worry, I already knew I'd be changing rollers, tips, and liner if I went super small on wire size.  I will be interested to hear more opinions as well.
Reply:Even a nylon or teflon liner puts drag on .023 wire that it birdnests at the drive roll.  308L is sooooo dang soft that I use .030 size wire in my Linclone SP-170T.Starts easier if you clip the wire on each start too.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:Hmmmm.  I also have a 30A spoolgun.  Kinda hate to hold that monster up for the whole job though.
Reply:Originally Posted by tbone550Hmmmm.  I also have a 30A spoolgun.  Kinda hate to hold that monster up for the whole job though.
Reply:Tbone,The .023 wire and tri-mix is probably your best bet.If it were me though, I'd want a smaller gun on the 12RC.I've used the M10 with a 10' wand on my 12RC and it works well with .023 wire.Also have a Bernard Q200 with a 15' wand, that I like for .030 wire.The M10's small size makes getting into tight spots easier and the 10' wand has never had a problem with .023 wire.I'd use the 309 for the mild steel/SS connection, and 308 for the rest.I've got my "spare" M10 gun in the storeroom.  If you want to give it a try on the 304, drop me a PM.  I really don't use that setup that often.  Most of my work is in the shop and I'll just use the HH187 with a H10 gun.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:Shovelon, you're right - there's nothing more frustrating than equipment that won't work.Sundown, excellent suggestion on the M10.  I had always pooh-pooh'ed that gun as an el-cheapo, but then again I'd always been working with higher voltages that were really out of it's ideal working range, and the 10' lead was always coming up short.  But for this job, my 15' long 300A gun is going to be a little big to deal with and I can see the advantage of using a shorter lead in this situation.Thanks also for the offer on using your M10, it's very much appreciated.  One of my customers has one of these that I can borrow to try out if I need it, so I'm covered for that.  But thanks again.Is there a standard tri-mix gas?And what advantages will running 308 on the SS-to-SS connections give me over using 309?  Just curious so that I'll understand better.
Reply:"Slightly" better corrosion resistance.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:"Standard" tri-mix is 90% He, 7.5% Ar, and 2.5% CO2. Though I usually think of it as overpriced snake-oil, it is probably the best gas for your situation.Preventing the end of the tubes from melting can be an SOB under the best of circumstances, but in my experience .030 wire isn't really any worse than .023, and it's cheaper and easier to feed.Good luck, sounds like a loooong slog!JohnA few weldersA lot of hammersA whole lot of C-clamps
Reply:Finally got everything nailed down and started this job today.  It is a security fence made to the customer's design, entirely from stainless steel.  It will end up being a little over 300' long.  The design is simple, but I think it will look OK.I was up until midnight last night building a cart out of scrap steel for the XMT and Suitcase, but I will spare everyone from having to see it.  It is an eyesore to say the least.  A functional eyesore.  One of these days I'd like to build a tool exactly like I want it to be, but there can only be so many non-billable hours in the day and I'm not in this for my health.As predicted, I'm running into a little trouble with the Suitcase, big 400A gun, and .023 wire.  I've got an .023-.040 liner in it (smallest one Miller makes), .023 drive rollers and .023 tips.  I'm using a 10-lb spool of 308L wire and tri-mix from Arcet which is 60% Argon, 38% Helium and 2% CO2.This is the first time I've used MIG for stainless and it is a lot different -- seems to need a lot more wire speed for the voltage compared to steel.  Also, I have to work the puddle on both pieces or I'll have cold lap on one or the other - can't just run down the middle of the joint like I can with steel.I had birdnesting problems at first but reduced drive roller tension and got rid of that.  I'm still getting erratic feeding but the beads are wetting out OK and look decent as long as I work the puddle like I said above.  Today's welds are flat and vertical down, welding 1.5" x .120 wall horizontals to 4" x .188 wall square posts.  I'm not welding the bottoms of the horizontals at the customer's request, although I did try a few on scrap for my own info, with results below.  I tried some overheads and was getting some odd failures.  The normal "crackle" sound disappeared and I got a soft hiss, accompanied by complete failure of the filler metal to bond to the joint.  It just balled up and fell off - never seen that happen before.  The wire was superheated and melting before it made contact with the joint, kind of like spray, only at a very low voltage.  It was also burning back nearly to the tip, then sticking out and touching the joint, burning back, etc.  This was at 20.5V and 410 ipm wire speed, the same setting I was using for flat and vertical down.  I thought it was gun angle causing the drive rollers to slip and slow the feed down, but they pushed the wire OK when I duplicated the angle pushing wire into thin air beside the joint.The pickets will be .065 wall 1" square fillet welded to the .120 wall 1.5" square horizontals.  When I tried this on scrap today, I was using 19.7V and 380 ipm wire speed, or something like that.  My notes are in the truck and I really don't want to see my truck again until tomorrow morning so I ain't going out there to check.I have the arc force set at around 20% on the XMT and haven't really tinkered with it much except to turn it down from 50% in an attempt to help the puddle wet in some.  Hard to tell if it helped - I'm learning that outdoors MIG welding with small stainless wire holds a lot of variables.Here are a few questions if you're still reading:1) Any ideas what was happening to the overhead weld?  I don't have to make any of these, but was just giving it a try to see what would happen.2) I haven't used wire this small before - how much voltage can it handle?3) After seeing the settings I'm using, any suggestions?  They are literally seat of the pants - I only had a few pieces of scrap to test on and no prior experience.  Sorry I didn't think to take pics of the beads - I can try to remember to do this if anyone wants to see.Thanks for any advice.  I know I wrote a book here, but I'm so tired I was afraid I'd leave something out if I didn't.Last edited by tbone550; 03-01-2012 at 10:05 PM.
Reply:That's an odd tri-mix you're using there- from what I understand it's usually used for Inconel and other Nickel alloys, never seen it used with stainless.The problem you're having with the wire burning back on overhead welds is something I definitely have experienced using 97& Argon/3% CO2 which is what I generally use with stainless. I would have thought that the addition of Helium would mitigate that problem but maybe not. Any chance of getting the tri-mix formula that I mentioned in my previous post? It seems to be the most popular for short-arc stainless.When I have had that problem I usually turn the voltage way down until it goes away, but that usually comes at the cost of a cold bead with lots of spatter. I don't suppose you have an Optima pulser for that XMT? Overhead stainless is an application where pulse really makes a major difference. It's easy to solve problems by throwing money at them On the subject of the gun, they generally warn you against using a gun longer than 10' for wire that small, and an .040 liner has lots of room for the wire to boogie around in. When I have to use small wire extensively, I've been known to take the gun from my little 120V MIG and put it in the feeder with an .030 liner. I mostly have Lincolns and I'm not sure you can do that with your Suitcase, but it may be worth a try. The short whip can be a pain in the neck but the smaller, lighter gun is nice for long-term use.Anyway, good luck, and keep us posted.JohnP.S. Just noticed Sundown had made much the same suggestion of lighter, shorter gun- my bad for not looking at earlier posts!Last edited by Silicon-based; 03-02-2012 at 10:47 PM.Reason: Noticed earlier postA few weldersA lot of hammersA whole lot of C-clamps
Reply:Hey John, thanks for the reply.  As far as the mix goes, that's the one my LWS told me I needed.  It is possible that they got it confused somehow with the correct mix.  I spent some time last night doing the research, and you're definitely right on the mix recommendation.  I'll have to see if I can get it.Yes, if I needed to do overheads the burnback could be solved by turning V down, but I'm already at what I consider to be minimum penetration with this .023 wire on the .120 wall to .188 wall fillet joint.  I did try turning wire speed up, but that just turned everything into a sputtering mess.  I have had trouble finding voltage and wire speed recommendations for this smaller wire, although I found plenty for .035 and up.  I think I'm at the limit of what this diameter wire can handle, but without a chart I'm not sure.One thing I'm noticing is that the welds and the HAZ turn a dark gray upon completion.  Is this normal?  The stick welding I've done with stainless has always ended up with a rainbow-type color when the flux was knocked off.
Reply:Do you have enough of the heavier-wall tube to justify a roll of .035? It'd make your life easier.The grayish color is normal, but it's a very thin oxide layer and it cleans up nice with a light wire-brushing. If that suitcase has a postflow function, turn it up to 3 seconds or so and keep the nozzle over the crater until it expires. Working outdoors doesn't help either, of course.A few weldersA lot of hammersA whole lot of C-clamps
Reply:Tough call on the heavier wire.  I only have 180 of those joints to weld, each one having 4.5" of bead length.  I don't have a feel for how long a spool of this .023 is going to last.  If the single 10-lb spool isn't going to be enough for the whole job, a spool of .035 now for the horizontals would make sense and I could save the .023 for the .065 fillet joints which will all be done last.No postflow on the suitcase.  I am using a windbreak, and I've got the gas at 40 cfh to try to help out as well.So far the job has been an exercise in frustration, but I think it will get better.  It always takes time to iron out a new process.
Reply:So I have a few questions on this too. I've a s.s. pipe hand rail job coming up, how are the welds looking, are you having any burn through problem? How easy is it to fill gaps? I'm need to decide if I need to invest in a portable Tig or if my sp 125 will handel this and I should pick up the stuff to run .23 wire. This is weird job it's in a cave and I only 120 vac available.
Reply:Caveric, I trust these welds for the security fence because their biggest danger is getting run into by bad drivers parking their cars in the lot.  In that case I'll be replacing fence sections anyway.  As far as use for handrailing goes, I would trust them on the .065 to .065 welds I'm making - the wire supports a high enough voltage to make the walls of the tube sag internally at the weld which means I've got more than enough penetration.  I am less trusting of the butt weld attaching the .120 wall horizontals to the .188 wall uprights.  It will be fine for security fence, but I would not trust it for daily use on handrailing.The welds look fine - I would show you pictures but I forgot to take any on Friday due to an early shutdown for rain, and I can't work on it today because of snow.  The beads are wetting out OK, and everyone who comes by is complimentary of them.  There isn't excessive spatter to clean up.  You get a solid dark gray color to the weld and about 3/4" around it in the HAZ.I could potentially have burn-through problems with the .065 tubing, but I'd have to be really screwing up for that to happen.  It is very easy to bridge gaps -- I'm using about 1/16" gap on the thick butt welds.  I'm cutting my horizontals short to create a gap for better penetration.If I had to do it again, I think I'd go with .030 wire for this particular job.  But with $100 invested in the roll in my feeder, I'm going to use it.  I would also spend the money for a 10' gun as recommended above.  The wire is trickier to feed in a 15' gun, but in my situation it can be done so far.  If I had less room to spread my equipment out and keep the liner straight it would be a real problem.Last edited by tbone550; 03-05-2012 at 09:03 AM.
Reply:thanks, is your lack of trust due to penitration issues or is it a brittleness issue? Is the discoloration leading you to believe that theres a lot of extra heat going in the the weld .
Reply:I wouldn't trust .023 wire on tubing much thicker than .065, because of penetration.  For example, I can't get a 'hot' enough weld on .120 tubing to make it sag like I can on the .065.  On an unknown like this, I like to figure out the settings at which my machine is capable of overpowering the material, and then I back off on the power to arrive at a final setting that isn't destructive.  At that point I know I have the penetration required. As I understand, the gray discoloration is a normal effect from the stainless being welded with this method, as Silicon-Based was explaining above.I'm not concerned about brittleness because this is a security fence.  Simply a visual deterrent to keep undesirable people from walking across the lot of this particular business and disturbing customers.