Butt welds with different material thickness

[STRENGTH AND POWER]

In one piece I build, I make what ends up being a butt weld where 2 x 2 x 11g square tubing meets up with 1/2" x 2" flat bar. With the material being drastically different thicknesses, what recommendations do y'all have as far as settings?
My setting were as follows:

Machine: Miller 350P
process: pulse
wire: .035
Gas" 90/10 @ 35cfh
base setting 300
arc length 50 ( factory)
arc control 0 (factory is 25)
Direction of travel - Push

I deburred the edge of the tubing but did not bevel. Fla bar was not beveled either. It doesn't make sense to me to bevel too much as the tubing isnt extremely thick. If I bevel the 1/2" there ends up being a gap unless I only slightly bevel to match up with the tubing.

For reference, the settings for 1/8" is 250 and 1/2" is 650 on the chart.

By turning the arc control to 0, I was looking to get a flatter bead.

Finished bead gets minimal finish grinding with a flap wheel followed by wire wheel.

Desired result is 1) a sound bead. 2) a good looking bead that requires minimal clean up

Thanks in advance for replies

Scott

[Diverdude]

I don't remember the settings I used and don't have gages on my machine but I welded this Wednesday, it's the top of my welding table I just built. Its 14 gauge 2" X 2" square tube to 1/2" plate. I'm using a MM211 with 75/25 gas and .030 wire. I think it was set at about 5.5 with a wire speed of about 65 on the dials but have changed them since so unsure. just sanded to debur, no bevels. I don't have a pic with me but also have a place on it with 11 gauge flat bar welded to the 1/2" plate will try to check tomorrow.half to 14g.jpg

[SundownIII]

1. Not what I call a butt weld. Filet.

2. You're making this a lot more complicated than it is. I know you got a great machine with a lot of bells and whistles, but, like fast cars, just because it will run 160 MPH doesn't mean you drive around town at that speed.

The weld I see in your photo could easily be done (with proper technique) using short arc and would look a lot better. The weld only has to be as strong as the weakest component, in this case the 11 ga. square tubing.

I'd suggest spending more time on developing proper technique and less time on fancy pulse settings on your machine.

Not trying to put you down but that, to me, is an ugly weld that I wouldn't be happy showing as representative of my work.

When you get to something that "requires" pulsed spray, post up some photos and we'll give some recommendations to get you headed in the right direction.

[JSFAB]

I do things on a regular basis very similar with what you pictured ,,,, only with 1/4" tube. Normally I bevel the tube. In your case, you could put a small bevel, on the outside edges of the flat, and running with correct heat and correct technique, end up with a very flat correctly-sized weld as strong as is necessary, given the size of your tube, and much more attractive. No grinding needed.

[davedarragh]

S & P: Sundown's right on his mark. Fillet welds are always based on the thinner of the two materials. Adding more filler does nothing for the strength of the weld, it only wastes consumables and time.

Here's a formula you can jot down for fillets, where the strength of the weld matches the plate.

Full Strength Weld: (w= 3/4 t) Material less than 1/4" = 1/8 w

You would only need a 1/8" fillet to weld the square tubing to the flat bar.

Fillet welds are measured by the leg size of the largest right triangle that may be inscribed within the cross-sectional area. The throat (a better index to strength) is the shortest distance between the root of the joint and the face of the diagrammatical weld.

Fillet weld gauges are a handy tool to keep in your tool box. I've got a set from Harris (#MWFG) and measures both concave and convex fillets.

Takes a lot of guess work out of fabricating.

I probably would have used a 7018, and made some real pretty fillets, but, that's me

Just set your MIG for short-arc, for 11 ga (1/8") material and squeeze the trigger

Dave

[fabricator]

How i'm seeing it, this is considered a square groved butt weld.I dont see how it can be considered a fillet weld when both pieces to be joined are flush at the top. I know the inside is a fillet but the other 3 sides are flush.
Putting a slight gap between the two pieces would give a complete fusion weld.It also allows less stress on the weld due to contraction.

[Sonora Iron]

I’m gonna get me one of those 350P’s one of these days.

But until then I’m stuck doing things the old way. Personally I’d set the machine where it was just a tad cold for the 1/2 inch flatbar, then I’d run a “J” pattern keeping the long part of the “J” on the 1/2 inch flatbar, only dipping into the 11-GA tube to stitch it up. Back up on the thick part move forward dip back into the thin part. Repeat as many times as necessary!

[STRENGTH AND POWER]

1. Not what I call a butt weld. Filet. I guess my understanding of a butt and filet weld are wrong, I will keep reading The procedure handbook of arc welding

2. You're making this a lot more complicated than it is. I know you got a great machine with a lot of bells and whistles, but, like fast cars, just because it will run 160 MPH doesn't mean you drive around town at that speed. This was the first time I adjusted the "bells and whistles". In other posts, I have seen, the OP wants weld advice but doesn't give any info on settings or pictures. Y'alls time is valuable so I put down everything I had to eliminate guesswork.

The weld I see in your photo could easily be done (with proper technique) using short arc and would look a lot better. The weld only has to be as strong as the weakest component, in this case the 11 ga. square tubing.

I'd suggest spending more time on developing proper technique and less time on fancy pulse settings on your machine.Any advice you can give to this end is greatly appreciated

Not trying to put you down but that, to me, is an ugly weld that I wouldn't be happy showing as representative of my work.A) what do you see that makes it ugly and B) What do you suggest to make it better?

When you get to something that "requires" pulsed spray, post up some photos and we'll give some recommendations to get you headed in the right direction.What would be a good example where pulsed spray is desirable over short arc?

I appreciate you taking the time to comment

Scott

[STRENGTH AND POWER]

I’m gonna get me one of those 350P’s one of these days.

But until then I’m stuck doing things the old way. Personally I’d set the machine where it was just a tad cold for the 1/2 inch flatbar, then I’d run a “J” pattern keeping the long part of the “J” on the 1/2 inch flatbar, only dipping into the 11-GA tube to stitch it up. Back up on the thick part move forward dip back into the thin part. Repeat as many times as necessary!

As this joint is 2" long, how many J's should I be looking for?

Thanks

[Sonora Iron]

As this joint is 2" long, how many J's should I be looking for?

Thanks

Oh I have no idea.
I watch the puddle, and the fusion line. If the thinner material gets so hot that I cannot control the puddle, and the puddle is about to fall in, I’ll stop, move to another location. If my production suffers by having to do this too many times, I’ll change settings, or technique.
Never done it with a Mig welder, (because they’re fantastic at filling gaps) but with SMAW a lot. Knock the flux off another rod and use it as a filler in one hand while welding with the other, (same technique as O/A or Tig welding).