View Full Version : welding advice

01-29-2006, 09:36 PM
I am just learning to weld, I have some 3/16" steel tube I am working with. I am making a T with it. The fillet weld sides I have gotten to look pretty nice and even the corner transition looks not to bad. I am having trouble with the side that is similiar to a butt joint weld. I just does not weld good, and some of my joints have a small gap. And advice?

Lincoln 175amp
Instructions say to use .35 flux wire, which is what I am doing.

I welding some together, and threw them as hard as I could on the concrete and the didn't break, jumped on them too. Guess it doesn't look good, but at least it is holding.

01-29-2006, 10:09 PM
A welder once told me that a bad looking weld is just that, bad. I have the same welder and practice make better. Round tubes are tough to weld! Start with two peices of flate or some square tube. Lay them out just as you have the round tube. Practice until you get good smooth purdy welds. Then work on the round tube. Keep a steady hand, proper angle, watch the puddle, be sure you are dragging the puddle, not pushing it. It should come out looking purdy. Good luck, keep welding.

01-29-2006, 10:51 PM
A welder once told me that a bad looking weld is just that, bad.

A truer statment has never been said!

now for the confusion :D

A bad looking weld is bad, but, may work.

a good looking weld isn't neccessarily a good weld! (I have seen some doosy's!)

This is not a Spec anywhere that I know but the weld should be as thick as the wall that is being welded (this is the eyeballers rule of thumb! ;) ) so .120 tubing should have a 1/8 (minimum) weld going around it.

just for and example I knew this guy that could weld the prettiest nicest looking evenly spaced weld you ever saw, but he wouldn't weld bigger than 1/8" so all his welds were very strong in 1/8" and under material. Not so much on the 1/2" plate (if you know what I mean)

Tube are hard to weld follow Rcazwillis's advice start with flat plate and work up. Practice makes perfect! or more precisely perfect practice makes perfect! ;)

01-30-2006, 08:35 AM
Sorry, this is square tube. I practiced some more. The fillet sides are looking nice. The butt joint side still leaves a little to be desired. I think it has to do with the metals are not touching cause of the round corners on the quare tubing. So when you butt up to that corner there is some gap there.

01-30-2006, 02:36 PM
gap is not a bad thing.

Depending on the standards you pulling info from, alot of specs require a gap about the same thickness of the material to be welded.

So .120" wall tubing with a .120" gap would be ok. Provided your welds are looking ok. Most tubing guys I know like to have ZERO gap which welds the prettiest. and As Long as your welder can penetrate the desired wall thickness, that is the way to go.

practice practice practice practice practice practice :D

02-01-2006, 08:54 AM
It is only a guess, but you said you are using flux core, that combined with a gap and the fact that your fillets are really nice, I would think you have too much heat.
Is the weld kinda sagging through?
Try turning her down 20% or so for the gapped welds.

02-01-2006, 09:04 AM
Will try that. Would this be better to do with MIG, the book from what I understand doesn't recommend MIG for 3/16". I am using a Lincoln Pro MIG 175.

2" sq tube, 3/16"
.035 flux core
Lincoln welder setting at D-4(book says D-2 for 3/16" using .045 flux)

02-01-2006, 09:09 AM
I welded the 2 1/2 square 3/16 wall for my rotissery for my car. I know what you mean. I built the radius up on the cross tube with multiple passes to fill the gap. The guys that do this all day use thicker wire so filling a gap isn't as big a deal. Lots of machinery I see you can't even see the radius. Flat across. I just did the best I could and tested them. I stuck a 10' long 2x2 tube in the end and stood at the end of it. 2000 ft *lb.

02-01-2006, 10:10 AM
Flux core is overkill for all general purpose welding. My weld shop is CWB certified and generally we only use flux core on heavey plate requiring high strength applications.
I would use 030 ER70S6 wire. A 175 Lincoln (IMO) is not big enough to consider 045 wire.
Are you using sheilding gas? You can get away without it with fluxcore but it is still better to use it.
I would make that same weld with the wire above at highest or second highest setting, but fluxcore is higher penetrating.
I wonder if you arent moving to slow, it is amazing how fast you have to move to make a weld that will pass an Xray test with a MIG. Theoretically the wire needs to contact the steel ahead of the puddle.

02-01-2006, 12:52 PM
I agree with darebee.

Its been awhile since I've had to X-ray anything (my superpowers are fading with age ;) ) but I have always been on the fast side of welding (too much caffeine w/ADDS) ) But from what I remember speed was dependent on the technique you are using for the weld. Also on what X-ray spec your using. Sounds like darebee and me use a similar technique, with the speed, but some of the senior welders, welded much slower than me and still got theirs to pass an X-ray.

02-01-2006, 05:10 PM
X-Ray superpower combined with ADD sounds like a deadly combination, good thing it is fading

02-01-2006, 08:03 PM

don't think the adds will ever go away! ;)

But on the plus side of that disorder (never thought hyper would be a disorder) I look younger than i am becuase of my high energy level! I fit in with all the youngens!

02-02-2006, 12:09 AM
Flux core is overkill for all general purpose welding. My weld shop is CWB certified and generally we only use flux core on heavey plate requiring high strength applications. <snip>

Are you using sheilding gas? You can get away without it with fluxcore but it is still better to use it. <snip>

but fluxcore is higher penetrating. <snip>

DareBee, you've got me confused. I was always under the impression that fluxcore wire was used in lue of shielding gas. I've always worked w/ it under the understanding that when working in the open [ outside in the wind] that fluxcore was better because it protected the weld better. Shielding gas will blow away in the slightest breeze. If you don't use fluxcore and no gas then your welds won't be worth crap due to oxidation and porosity.

As far as higher penitration or the need to use it on heavyer plate, this is news to me. We too are CWB cert'd and don't use it simply because you can generally make better welds w/ gas, we use both Blue Shield and Argon depending on the job and parameters.
Please expand on this so I can better understand. I don't claim to be a great welder but I'm learning....

<edit> I did some more checking and DareBee, your entirely correct! The fluxcore is better at penetrating the heavyer welds. What had me confused was that none of the guy's here use Fluxcore on their heavy welds. The reason being is they use Metalcore which has even better penetration. It still needs a simple shielding gas [ I think it's CO2]. I'm learning!

Sorry if the above sounded like I was contradicting you.. It wasn't intended that way ;)