Buying Bigger MIG

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Steve in Central Texas here.  I have been doing a lot of welding lately, making metal shelves for my new 30x40 shop, building a 8x18 flatbed trailer, and a 40x70 steel building frame dor a Buddhist temple.I have always had a mindset that MIG/FCAW are for thinner stuff like 14 ga and anything else is SMAW.  I have a 105 amp 110v Lincoln MIG and a 235 AC/DC buzz box. I rarely bothered with MIG - just never got around to trying it - I am essentially an old farmboy welder.I have been using the buzz box to weld up the trailer, which I am building out of a salvaged house trailer frame.  I don't think I ever got a really satisfactory weld with the buzz box no matter what rod/voltage/amperage/cleaning combo I tried.  Apparently the stuff, which is nominally 3/16" x 3" x 8" I-Beam, just seemed to resist any effort to make a pretty bead.So I went out and got a bottle of 25/75, hooked it up, and started welding, with the power pretty well maxed out on the Lincoln.  Lo and behold, the welds were really great except for the occasional gnarly one.  I decided to look into a bigger unit that would pretty take over all my 3/8" or less stuff and sell off the smaller stuff.  I have been following the prices on new and used Millers, Lincolns, and Hobarts on Ebay, and through the retail outfits.  I have a budget of $800 and that pretty much limited me to 110v stuff or used.  Used doesn't have any sort of warrantee.In the end I settled on an Everlast 200 Amp machine.  I made a bid to Alex and got a new 2011 machine with a 5 yr warranty for a phenomenal price, with room for a new helmet in my budget.  The new models ship in two weeks.  This one is an inverter with 160 A stick and arc force control, something I have learned to love on a stick/TIG/plasma machine I have.I won't go into the American vs Chinese argument, but this machine represents a lot of value for the money, appears to be well supported, and there are enough of them around that parts and repairs are easy to obtain.  The recent aborted throw down challenge impressed me in that the seller of the overseas equipment seemed quite confident in his product.  If I could afford a new red, grey, or blue unit I would buy one in a heartbeat but the used stuff and cost to repair seemed more risky then buying an Everlast;Steve
Reply:Steve,Frankly, this is a very disturbing post.You seem to like playing "Russian Roulette".If you couldn't get an acceptable weld with your AC/DC buzzbox, then mig is NOT the answer.  Mig can produce what, to an inexperienced welder, looks like a good bead that WONT HOLD SH1T.Large, over the road trailers, ARE NO PLACE to be learning to weld.You already had a welding machine BETTER SUITED to welding on your trailer, than the Chinese junk you spent your money on.If you're not willing to put in the time/effort to learn proper welding techniques, you have no business welding on anything that "goes over the road".  A Chinese "squirt gun" welder is sure as he11 not the answer.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:I agree with Sundown here.  Work on your stick.  You should be able to put down a nice clean, pretty and fully penetrated weld with the stick welder.  If you can't do that, your MIG welds may look pretty but my guess is that they aren't good welds.  On the trailer side of things, stop.  If you can't lay a good weld with the stick, it isn't going to be safe.  The MIG you're using isn't powerful enough to weld a trailer frame together.  Don't kill yourself or someone else because you decided to do something you shouldn't.--Wintermute"No man's knowledge here can go beyond his experience." - John Lockewww.improvised-engineering.comManufacturer Agnostic:Blood----------Sweat---------Tears----|------------------|----------------|----Lincoln Red, Miller Blue, Esab Yellow
Reply:I'm kinda worried about that 40x70 steel framed bhuddist temple he built, if he had that much trouble modifying a trailer, couldn't get the stick welder to work that he's been using for most of his life and only had a 110v mig besides the stick.  Who did the welding on the temple and with what machine?  I hope there are no earthquakes in that area.MM350P/Python/Q300MM175/Q300DialarcHFHTP MIG200PowCon300SMHypertherm380ThermalArc185Purox oaF350CrewCab4x4LoadNGo utilitybedBobcat250XMT304/Optima/SpoolmaticSuitcase12RC/Q300Suitcase8RC/Q400Passport/Q300Smith op
Reply:the advantage to welding buddhist temples is the automatic post weld stress relief.XMT 350 MPa, w/D52-DTA 185 TSWHarris of
Reply:This trailer is a flatbed.  The main part of the frame is 5' x 18' made from I-beam with 4x 6 angle on 24" centers going crosswise, Triangular "outriggers" on 24" centers extend 18" out from either side.  A 2" x 2" x 1/4" angle will be welded to the outriggers all the way around the trailer, and 2" x 10"s will make the floor. I can't send photos through mu ISP (Hughesnet satellite: upload speeds are around 25kbps) or I'd send a few.The frame was welded up by a certified welder and myself in a horizontal position on a jig we put together so we could shoot the verticals with a transit.  We used with 5/32" 7018 at 135 amps.  These welds look good  Where I ran into problems was welding the outriggers on which had to be done in a vertical position.  These are made from the same I-beam stock and are welded (teed) on to the flange and web of the I-beam frame and are on the same 24" centers as the cross piece angles.  I did the welding on them myself on both sides of the webs and flanges.  When I say not pretty, the beads are consistent but not smooth. They aren't much worse than I see on the older ag equipment I have.  I am not the greatest uphill welder and I just couldn't find a sweet spot.  Best luck I had was doing a "C" stitch into the puddle and pulling the rod back a bit at the ends of the C.  When I ran the MIG beads I ran tight arc and did the side of each flange in a single pass and it left what I consider to be a nice fillet weld in a third the time of the stick bead.  Both welds passed a "sledge hammer" test with the metal yielding before the welds on the sides and top.  I also cut up a sample through the bead and penetration looked good.  I have a feeling the nice looking welds on my ag equipment was made by MIG the rougher welds were stick.  I worked as an engineer in a military aircraft overhaul shop and did failure analysis and process certification work using things like scanning electron microscopes. I don't think there was stick welder in the place.   I am a little short on the hands on side but long on the quality side of metal working so I am counting on you guys to keep me straight with the practical stuff.  This is my fifth trailer and so far as I know the other four are still on the road.  This one will have 6,000# axles and tires, and 10,000# coupler but I will probably register it as a 8,000# GW.Steve
Reply:The Buddhist temple is 40' x 70' with a center roof 30' high on a 9 in 12 pitch and a lower outer roof at the 18' level on a 6 in 12 pitch.  We rented Lincoln Ranger 250s.  Main problem around here is wind.  The sheeting is on the roofs but the temple is waiting on more money for the metal studs and sheathing.  I just finished my weld up 30' x 40' x12' building about six months ago.  The structural red iron welds much easier than the house trailer frames.  It may be a situation like that of using angle iron bed frames.  I notice the assembly welds on the frames aren't always pretty either.  I am not sure why, but the shielded MIG process just seems to make a nice bead no matter what.  For the record, I was very meticulous about grinding the joints clean and v-grooving the joints to be welded.  Even with MIG, I'd hit a piece that was gnarly.  In the past I've used structural red iron for my trailer projects.   Go figure. Wish I still worked in that lab or I would.Steve
Reply:5/32" 7018 at 135 amps is cold, which would contribute the lumpy beads you're describing.  On 3/16 metal, 1/8" rod would have been fine.  Were you running the 5/32 rod cold due to overheating the metal at say 170 amps, which would have been a more appropriate setting for 5/32 rod?For vertical-up, hold the toes and zip across the middle.  Going straight up the middle would also contribute to the lumpy beads.  The bigger the rod, the bigger the puddle and the harder it is to control out of position.  1/8 rod would have been helpful here if vertical up is not your thing.MM350P/Python/Q300MM175/Q300DialarcHFHTP MIG200PowCon300SMHypertherm380ThermalArc185Purox oaF350CrewCab4x4LoadNGo utilitybedBobcat250XMT304/Optima/SpoolmaticSuitcase12RC/Q300Suitcase8RC/Q400Passport/Q300Smith op
Reply:Using 1/8 at a higher setting makes sense now.  I can lay a pretty good bead on anything flat up to 45 degrees but up has escaped me.  Lumpy beads describes them  well and controlling the puddle has been hit or miss at times.  Thanks for the info.  I definitely an looking forward to getting the new 200 amp MIG though.  Steve
Reply:This may sound odd since you've been welding for a while, but consider doing (whatever the process) a couple of days of practice coupons so you can fine tune for progress without variables of working on a project. Clean off your scrap so you are practicing on clean metal, and post pics of your welds along with settings and wire material/maker in this thread.
Reply:That is good advice, thanks, Farmall.   I knew that, too. I tend to go a month or two between major welding projects save for quick and dirty repairs,  I lay off welding for a while and take up some other interest like woodworking and metal turning/grinding.  Then I jump into a new project and it always takes me a bit of time to get up to speed.  I do fine when there are few variables but throw in some old rusty metal, possibly questionable rod, out of position welds and old timers disease and things don't always go as I want.I do great in everything but vertical for some reason I just can't seem to keep the puddle from running.  From what I picked up here I may be welding too cold with too big of a rod and am open to other suggestions.
Reply:Post up some picts of your attempts, with the machine, settings, gas, material thickness and so on. The more info we can get, the better the answers will be..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 stevewmI do great in everything but vertical for some reason I just can't seem to keep the puddle from running.  From what I picked up here I may be welding too cold with too big of a rod and am open to other suggestions.
Reply:Makes sense now that a .030 MIG wire at 105 amps will leave a really nice bead but a 5/32 7018 rod at 135 amps won't.  It seemed like it took some time to get enough heat in to get a puddle on a 1/8" arc but then gravity would take over almost instantly.  With the MIG with a vgroove on at the fillet of the smaller piece I would get a nice puddle. Then I just brought the puddle long just before the puddle began to freeze.  I pretty much had no drips, no runs, and no errors.   I will try to post some pix but I am not sure if they will go through.  I get on the internet through Hughesnet satellite.  The download speed is about double that of a fast phone modem but upload speed is only about one fourth of that.  I live way out in the boonies on part of an old ranch miles from pavement with no broadband or DSL and even a crummy phone connection.  And no, my cell phone signal strength is pretty poor.  But on the other hand a flock of wild turkeys live in my front yard, there are bass in the front and back creeks and the deer are like rabbits.Steve