Help with welding round tubing

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I'm building a bumper and need to weld some round tubing on it. I don't have a lot of experience with welding tubing. How do you guys get the beads to lay correctly when welding around the round tubing? Every time I've tried I get the weld piled up instead of laying nice. I have been doing a circle pattern when welding them before and the pile is what I'm getting. What do I need to do to fix what I'm doing wrong? The tubing is 1/8" wall 1-3/4" round. Thanks in advance for any help at all.I'm using a Lincoln SP-150 (220v) my settings are:Gas: C25Voltage: 5Wire speed: 150 IPMI'm running at about 18 volts.Last edited by medic2230; 09-17-2014 at 04:53 PM.
Reply:I've always welded them with stick. 3/32 7018 and I down hand them.JasonLincoln Idealarc 250 stick/tigThermal Dynamics Cutmaster 52Miller Bobcat 250Torchmate CNC tableThermal Arc Hefty 2Ironworkers Local 720
Reply:Small round tube/pipe is one of the more difficult things to weld well. When you weld on a flat piece, you maintain a consistant angle between your electrode ( tungsten, rod or wire) and the flat piece When you move to round, you must constantly change. If you think of any single piece of tube as a flat plate tangent to the arc of the pipe, that is your "flat" piece. Note though as you move around the pipe, the tangent line changes. though the relationship of that tangent line and the pipe directly under it doesn't. That means as you swing around you must constantly keep adjusting your angle to maintain a consistent angle in relation to that tangent line. Most people don't and try to weld flat across and the angle and arc length changes thru the weld..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:Would I be better off dragging the bead back and forth than using a circle pattern in that case to try to maintain the arc length? If I understand correctly it's the changing arc length going from close to further away to close that's causing the bead to pile up? I think I understand you saying that I need to basically move the gun in a U into the joint to maintain the gap while welding?
Reply:For tubing welding, Jody (Jodi?) over on weldingtipsandtricks.com has some videos that have some tips on making the circle with your electrode.  Here is a link to one of his videos.  There are a couple of videos on the page, this one is "Stick Welding Techniques and a Few Tips".  The part about rod position starts at about 3:44 into the video.  He positions his hands and makes a dry run, bracing his arms and hands and swinging through an arc.  Hope this helps.  It helped me a lot.http://www.weldingtipsandtricks.com/...ng-videos.htmlOOPS!!  Just noticed you were using MIG instead of stick.  Probably the same technique of positioning would still work for you.
Reply:Take a look at this thread and see if it helps. It's on stick, but the same basic principle applies with mig or tig.http://weldingweb.com/vbb/showthread.php...d-for-Tungsten.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:You don't need U or circles- 1/8" is thin. Stick the gun in the joint, pull the trigger and pull the gun around Try to get 1/2 way around then do the other side.Ed Conleyhttp://www.screamingbroccoli.com/MM252MM211 (Sold)Passport Plus & Spool gunLincoln SP135 Plus- (Gone to a good home)Klutch 120v Plasma cutterSO 2020 benderBeer in the fridge
Reply:Should I be pushing or pulling the puddle? Looking at what DSW said in the other thread I should be pushing, right?
Reply:Either way with MigEd Conleyhttp://www.screamingbroccoli.com/MM252MM211 (Sold)Passport Plus & Spool gunLincoln SP135 Plus- (Gone to a good home)Klutch 120v Plasma cutterSO 2020 benderBeer in the fridge
Reply:Originally Posted by medic2230Should I be pushing or pulling the puddle? Looking at what DSW said in the other thread I should be pushing, right?
Reply:Thank you guys! I'll try with your advice.BTW Ed that is one impressive set of Nikon camera's and glass on your website.
Reply:Originally Posted by medic2230Thank you guys! I'll try with your advice.BTW Ed that is one impressive set of Nikon camera's and glass on your website.
Reply:Make sure you can see the weld puddle. I sometimes have trouble and need to adjust my head to see better.Fireman BillHH 210 MVPMM 211 Spoolmate 100Lotas LTP5000D PlasmaOxy/Accet (Victor)Wards AC/DC buzz box30 ton old hyd pressA few brand name toolsA bunch of cheap toolsA wife to worry me and4 dogs to supervise me