welding question

Well as an Ironworker for the last 40 years you would think I would know the answer to this question. However I am puzzled. I am doing some panel repairs with gas welding methods. Having done this many years ago I remember using flux to dip my rods in. I did some thread searching on this site and found some good tips on methods for gas welding. No one mentioned using flux for this type of welding. I have some flux I am using
but it is for brazing. I need a little advice here. do I need to use a different flux or none at all? Thanks for any tips

 

R45 and r65 gas welding rod uses no flux

 

The only flux I've seen or used for gas welding was for brazing, aluminum and some stainless welds. Never used flux on good old steel.

 

Old metal coat hangers, no flux. We are about old school here.

 

Some gas welding rods have phosphorous added to make them self-fluxing. BUt for the most part, use a slightly gas rich flame and it will help deoxidize the surface.

 

28 years ago, I studied welding at Junior Colleg level. We were taught to gas weld (brazing) with flux. We used a borax flux for brazing with a torch and brazing rod. Don't remember much more. It did take a little finesse to not warp the ajoining sheet metals. I stopped brazing when I got a Mig welder. I did gas weld using flux the rear quarter panels on my '55 Chevy after taking the cl***.

 

I was also taught to gas weld with flux, & the brazing rods came precoated with flux (white) ?

 

Gas welding needs no flux. Brazing does. Different processes.

 

If you were using flux, especially with the rods with the coating, you were not welding, you were brazing.

 

OK cool. I remember heating the rod, rolling it in powder flux then heating the panels and rod together until they all became one. The flux was only to clean the area. I havnt done it sense the early 90's I only mig & tig now...

 

I try to gas weld steel a few times a year just so I remember how to do it.

No flux.

 

No flux when welding mild steel,only with brazing .
Use tig rod for gas welding if you desire.You can use a tig rod anywhere.U can use mig wire also for your fine work.Can't go backwards oxy rod is no good for tig.Tig and mig are e70s6 in most cases.Some tig is also e70s2 but still good for gas welding.

Tig

 

If you are welding steel with steel rod you don't need flux.

 

Putting it simply " gas welding " is fusing two pieces of metal together by melting both and they become one the rod is only a filler if needed. Brazing is attaching two pieces of metal by a alloy like br*** and sticking them together, the flux is to clean the areas to be stuck together. I have found that brazing under body paint always erupts because the flux reacts with the primer and paint.
The Mig can be used with a flux core wire or a argon mix but that is not gas welding it is
electric.
Tig is electric also it uses a gas for a flux.
Stick welding is electric uses a coated rod for a flux.
The most important thing is to carry the bubble in all possess. JMHO

 

Isn't the gas used to shield the weld area and keep air contamination out of the weld puddle? That's why TIG machines have what is called "post flow", where gas continues to flow from the nozzle for a short period after the arc stops. I don't think it performs the same function as flux does in brazing or soldering, which is to chemically clean the metal before the bond occurs.

My understanding is that the coating on a stick welding rod forms a shielding gas when the arc burns it. I believe the same is true of what is called "flux core" MIG wire, it's really not flux, but rather a compound that forms a shielding gas when it burns.

But then again, I may be wrong.....

 

^^^^^100%^^^^^^

 

Yup

 

This is true for arc welding. Gas welding as most of us understand the term is welding with an Oxi-acetelene torch. I have taken 6011 rod with the flux on it and pounded it with a hammer on the concrete to break the flux off and then used the bare rod as a filler rod using the "gas welding" heat source. I once gas welded a thread-o-let (a threaded bung that must have weighed 4 lbs) into an 8" pipe for a temperature sensor using this method. The bung was in the wrong location and they had taken the welder to another job. I used the cutting head to get the heavy metal hot enough to weld. It took forever but I got it done. 8" pipe will dissipate a lot of heat...and no flux of any kind was used. I was proud of that. I saved the company a lot of money.

Oh yeah I welded an *** load of exhaust tubing and mufflers together for several years just using the wire coat hangers that our uniforms came on every week. I still do but I have to scrounge wire coat hangers now.

 

Agreed, If you'll look at the post directly above mine (jimvette59) you'll see that I was questioning whether or not the shielding gas cloud (whether it be Argon, 75/25, your mix of choice, or the gas created by burning the coating on a rod or in a wire) really did the same thing as flux does when brazing or soldering. My contention is that it is a shielding cloud rather than a conventional flux that chemically cleans/prepares the metal.

The first floor I ever replaced was in a 1950 Chevy, gas welded with clothes hanger wire for filler. Worked well, lasted a long time.......

 

Hell Ebb,
My first chop was done in the street in front of a friends house and we used coat hangers and a torch to get it done.

I think that there is a difference that using electricity for a power source makes that using a flame for a heat source doesn't do. There must have been some cl*** that I have taken over the last 50 or so years that I should have paid more attention to so that I could come up with an answer to what the difference would be.

 

I do know the difference between welding and brazing. I just thought maybe some flux to help float impurities to the surface like a electrode
rod may be helpful. I said I was using some flux I bought thinking it was for welding but it was for brazing and was not happy with the results. I will try it with smaller rods, I was using 3/32 and think they may be to heavy and require to much heat to work with thin panels. Thanks guys for the replies.

 

i didn't google it or anything, but i think in brazing, the material isn't melted in a puddle it is heated and the lower temp filler metal fuses in. like said the flux helps it bond well. gas welding like oxyacet had been discussed.

 

hey, will one of those small bottle of mapp gas melt a coat hanger for small metal jobs, ?

 

i don't know if it will be concentrated enough to heat what you want to weld with it. you not only have to melt the "coat hanger" but the metals you are welding. the flame needs to be hot enough when you bring it closer it will heat quickly and back away it starts to cool. i like controling the heat with gas welding this way. and you don't want heat going in a big area to metal around the weld causing warpage.

 

Go with a 1/16" rod and you'll have an easier time working on thin stuff. I'm not a fan of coat hangers myself, I learned on the real stuff and have stuck with it.

Bob