Welding metals of different thicknesses

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How do you guys do it. Say a fillet with a 3/8 vertical  plate to a 1/8 horizontal tubeI will practice this but I wanted some input since Im not out in the garageThanks as usualScottMillermatic 180
Reply:Originally Posted by scott657How do you guys do it. Say a fillet with a 3/8 vertical  plate to a 1/8 horizontal tubeI will practice this but I wanted some input since Im not out in the garageThanks as usual
Reply:OK here are my first attempts 3/8 beveled on both sidesI got the puddle going and pushed  to the 1/8Welds 1,2, 3 were done with volts at 10 wire speed 60  thicker material was horizontalWeld 4 I upped the speed to 70 so I could push a little more material to the 1/8 tubeWeld 5 was done at 10  /70 but with the 3/8 vertical so I was drawing the puddle down.I like #4 the bestAll the pics are 3/8 up Attached ImagesScottMillermatic 180
Reply:It may be the pics... the weld face needs to be at a 45 degree or close to that for a filletYou probably heard this a 100 times    the weld leg only needs to be as thick as the smallest piece of material when welding two diff sizes.  In your case 1/8"  Looks like your fine on that.Try using a bit less travel and maybe a weave pattern. Keep sending some pics if you canThe final piece your going to be welding verticlal? weld it like you own it
Reply:Wait I think I understandIts a T joint and your using SQUARE tube?Because of the rounded corner in the square tube, if thats what it is, go slower and fill that gap with a weave and point up when you get to the vertical plate to insure some penetration like Tangleddiver mentioned about the heat.  See if I can confuse ya anymore  lol.Last edited by lewray; 10-25-2008 at 05:30 PM. weld it like you own it
Reply:4  has the best tie in to the 1/8 metal..
Reply:I should have given a better view of what I am doingAnd # 4 also had the better penetration on the inside of the 1/8 tube Attached ImagesScottMillermatic 180
Reply:Yeah there you go   T joint  We have to ask lol...whats it for? weld it like you own it
Reply:Just set yourself up with enough amps for penetration on the 1/8 steel as stated and weld away. You don't need anymore penetration on the 3/8 steel. Nice posts lewray, good advice .Miller DVI2Lincoln Precision Tig 225Thermodynamics Cutmaster 38Everything else needed.
Reply:Im practicing before adding suspension tabs to a hot rod frameSo Just set it up for 1/8 ?ScottMillermatic 180
Reply:What welder are you using ?I think you should set yourself up with gas sheilding over flux core for a project like that.Miller DVI2Lincoln Precision Tig 225Thermodynamics Cutmaster 38Everything else needed.
Reply:millermatic 180   .030  75/25ScottMillermatic 180
Reply:Sorry, for some reason I thought you were using flux core. The MM180 should do the job just fine. Keep practising and you will get it.Miller DVI2Lincoln Precision Tig 225Thermodynamics Cutmaster 38Everything else needed.
Reply:Originally Posted by lewrayIt may be the pics... the weld face needs to be at a 45 degree or close to that for a filletYou probably heard this a 100 times    the weld leg only needs to be as thick as the smallest piece of material when welding two diff sizes.  In your case 1/8"  Looks like your fine on that.Try using a bit less travel and maybe a weave pattern. Keep sending some pics if you canThe final piece your going to be welding verticlal?
Reply:Originally Posted by Go1lumthat statement about having a leg size that is at least as thick as the smallest piece is a farmers rule and not correct from an engineering standpoint. A weld only has to be big enough to hold up to the required loading types plus a factor of safety.
Reply:All the welds pictured appear cold lapped and have inconsistent travel speed. Take a sledge hammer and/or large pipe wrench to what you've welded and you'll see what I mean by cold-lap.Constructive criticism: You really need to practice the basics before moving on to more complicated joints. You must have the basics *mastered* before attempting to weld suspension parts. Here's what happens with cold lapped MIG welds on suspension parts: CLICK FOR VIDEO You can see how the ladder bars have snap off cleanly at the "welds".Practice basic butt and fillet weld coupons and perform destructive testing to analyze your welds. You will learn a lot from breaking your own stuff (and you won't have to listen to a bunch of grumpy old guys).After you get the basics down pat and your welds pass visual and destructive tests: To weld 3/8" to 1/8" with your machine: preheat the 3/8" leg with a torch and weld as normal. With selective preheat on the thicker leg, both legs will melt in at similar rates.Or: Redesign the bracket, weld 1/8" to 1/8" fillet, and bolt the thicker member in place mounted in "double shear".-Matt------------------------------------------
Reply:weave 45 degree work angle if your welding flat, favor the top (stay longer on the top in your weave)they'd run me off quick if i welded like that.