# Gas Welding Joints & Beads



## erikmannie (Jan 1, 2023)

I do a lot of gas welding. I was putting some stuff in the Project of the Day thread, but I imagine that most people aren’t interested in gas welding. That being the case, I made a thread just for gas welding!

This is the *back side* side of a root pass on 1” plate wherein the top side of the root pass failed to achieve full penetration.

Of course, I never intended to weld the back side of the joint, but I had to do so because of the failed penetration.

I used a #5 tip for all this, but that is *way too small* for 1” plate. I don’t think that anybody could weld such thick plate with a #5 tip due to the amount of available BTUs for all of that steel.




Now I am setting this plate aside & switching to .125” wall sheet…


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## benmychree (Jan 1, 2023)

I used to weld sched. 80 ammonia piping with an OX Acet torch, about 50 years ago, it was almost fun --- I have given up welding for the most part, my tremor makes it pretty much impossible.


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## erikmannie (Jan 1, 2023)

benmychree said:


> I used to weld sched. 80 ammonia piping with an OX Acet torch, about 50 years ago, it was almost fun --- I have given up welding for the most part, my tremor makes it pretty much impossible.



I am really sorry about your tremor. It is definitely fun when you have an appropriate sized tip (“welding nozzle”).

The set up that I have now is working almost perfectly. Almost everything is pictured, except for the stool that I sit on.


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## erikmannie (Jan 1, 2023)

I try to buy Victor equipment. I bought the no name 3/32” RG45 on eBay.

Today I have a #2 tip for the .125” sheet. Both acetylene and oxygen are set to 5 psi.

I very often watch oxyacetylene safety videos on YouTube, & I am very mindful about all the crucial safety tips.


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## erikmannie (Jan 1, 2023)

The 300 Series (large) combination torch that I am using today is heavier than it needs to be. It is putting unnecessary strain on my neck & back. I should have grabbed the 100 Series (medium) torch.

If it is at all possible, I take the time to use a poly-strip disc to remove the mill scale, & then I use a lint free rag & acetone (or ***chlorine-free*** brake cleaner in an aerosol can) so that I can weld on bright shiny metal. I am unhappy if I am not welding on bright shiny metal.


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## erikmannie (Jan 1, 2023)

Here are the first 4 tack welds executed in the horizontal position:


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## erikmannie (Jan 1, 2023)

Examples of cold lap:







One of my many disgraceful welding habits is finishing up a weld by washing the weld. Hopefully with practice I can get those toes to tie in on the first pass.

Gas welding is fantastic practice for TIG!


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## erikmannie (Jan 1, 2023)

One of the many reasons that I love gas welding is because it is retro. I love history, so why not step back into history & weld like they did?


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## Nutfarmer (Jan 1, 2023)

Bright and shiny metal? We very seldom see that on the farm. One place that acetylene welding is still required is aircraft frames of chrome Molly tubing. Heavy plate is so much easier to do with stock arc.


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## erikmannie (Jan 1, 2023)

Flat T-joint:


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## erikmannie (Jan 1, 2023)

Nutfarmer said:


> Bright and shiny metal? We very seldom see that on the farm. One place that acetylene welding is still required is aircraft frames of chrome Molly tubing. Heavy plate is so much easier to do with stock arc.



I can understand the lack of bright shiny metal on a farm.

I did not know that that type of aircraft welding required oxyacetylene, but I can definitely understand why that would be the case.

I am with ya on the arc welding for heavy plate!


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## benmychree (Jan 1, 2023)

Looks like Victor torch and tips, my favorite! I have the 300 series and the smaller series 100 one also, one of my old friend’s father said it all “I wouldn’t weld without Victor” he was arguably at least one of the best welders in Napa County, sadly, he died at age 56 of a heart attack and his shop was auctioned off, it was my friend and I favorite playground when we in grade school, and the first time I ran arc weld beads with a MG DC welding machine, his son, my friend lately lost his mother and is moving into her house, which was his father’s mother’s house, and right next door to where the shop was, also where he lived when we were in JR high and high school, so much nostalgia!

*Sent*


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## benmychree (Jan 1, 2023)

One of my cousins built a single place "Rotorway" helicopter back in the 60s from a kit, the frame was all torch welded 4130 tube, welded with a Victor aircraft torch, and yes, it is very much like tig welding, which I used to be able to do pretty well, mostly on 1/16" wall stainless tube; my shop made quite a lot of tools for winery production.


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## erikmannie (Jan 1, 2023)

benmychree said:


> One of my cousins built a single place "Rotorway" helicopter back in the 60s from a kit, the frame was all torch welded 4130 tube, welded with a Victor aircraft torch, and yes, it is very much like tig welding, which I used to be able to do pretty well, mostly on 1/16" wall stainless tube; my shop made quite a lot of tools for winery production.



I did not even know it was possible to gas weld on stainless.

The weld below needed to be washed for purposes of penetration as well as even distribution of filler material.

My first question: a problem that I am having is that there is a fair amount of gas pressure coming out of the welding tip! I will try turning down the pressures on both regulators to 3 psi to see if that reduces it. I have never seen this before. It would make a good gouging setup, but I am not trying to gouge.

It is very unfortunate when I use too much filler material. The #2 tip is not very effective trying to heat up that much material.







Back side. Ignore the tack welds.


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## benmychree (Jan 1, 2023)

The stainless welding was done with TIG, I thought that is what I said, perhaps I was mixing apples with oranges in that post.


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## benmychree (Jan 1, 2023)

Looks like too small of a tip using too much pressure, try a larger tip with less pressure/velocity.


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## erikmannie (Jan 1, 2023)

Here is the weld bead on the other side of this T-joint. I ran out of oxygen halfway through this weld bead. Once I installed a fully charged oxygen cylinder, I was happy to be operating with all of the heat that comes with a #2 tip.

This is a solid weld bead, but I will switch to a #3 tip now so that the work will go faster. Gas welding is slow.

Know that this weld bead has been washed again and again because I wanted to tie in the toes & assure myself of full penetration.

My criticism is that I used too much filler material & that it doesn’t look pretty.


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## tq60 (Jan 1, 2023)

The flame needs to "just be there", if it looks like it is a jet then too much gas.

You are running the regulators way to low.

You can do it that way, you open the torch wide open and adjust flame by regulator.

A friend did it this way and he was a true welding artist, the inspectors gave him grief over it.

O2 should be 20 to 25 and ace 10 to 15 if I recall correctly, been many years.



Sent from my SM-G781V using Tapatalk


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## erikmannie (Jan 1, 2023)

tq60 said:


> The flame needs to "just be there", if it looks like it is a jet then too much gas.
> 
> You are running the regulators way to low.
> 
> ...



It is definitely a jet. I had both regulators set to 5 psi for the second weld bead which is what Victor recommends in their chart, but I have seen people on YouTube use, e.g., 8-10 psi for a similar application.

I’m going to get some soapy water & check for leaks.

I also have another oxyacetylene cart, & I will try that cart with a different (medium) torch to see if I still get the unwanted jet force. I have gas welded a lot before, but I never remember having needlessly high gas pressure at the tip. Nobody wants a jet force here.


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## benmychree (Jan 1, 2023)

I will admit to having used higher regulator pressures and adjusting the flame that I desired with the valves on the torch, that is what worked with me.  If the flame blows the puddle out, it is too much pressure with too small of a tip.


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## cwilliamrose (Jan 1, 2023)

erikmannie said:


> I can understand the lack of bright shiny metal on a farm.
> 
> I did not know that that type of aircraft welding required oxyacetylene, but I can definitely understand why that would be the case.
> 
> I am with ya on the arc welding for heavy plate!


Most aircraft 4130 welding is done with TIG these days. I used to gas weld 4130 but TIG spoils you. Some factory aircraft welding is done with MIG but that's not the norm. And most aircraft tubing is very thin compared to what you see being welded in this thread.


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## mattthemuppet2 (Jan 2, 2023)

Erik, I forgot to ask, did any of those tips for your torches?


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## erikmannie (Jan 2, 2023)

mattthemuppet2 said:


> Erik, I forgot to ask, did any of those tips [work] for your torches?



Yes, 2 of the tips that you sent fit torches that I have.


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## mattthemuppet2 (Jan 2, 2023)

super cool! The ones that didn't fit will be a good excuse to buy torches to fit them


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## erikmannie (Jan 2, 2023)

Here is the first bead from today, another flat T-joint:




The only problems are that it is not pretty, there is some undercut, & there is cold lap on each end.

I used a different O/A cart (and a medium rather than a large torch) for this so all of the equipment is different than what was giving me the jet force.

I had no jet force, but I think this is because I bumped up to a #3 tip. Gas welding goes a lot better when you have enough heat. It is quite miserable when you don’t have enough BTUs.


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## paradox_pete (Jan 2, 2023)

cwilliamrose said:


> Most aircraft 4130 welding is done with TIG these days. I used to gas weld 4130 but TIG spoils you. Some factory aircraft welding is done with MIG but that's not the norm. And most aircraft tubing is very thin compared to what you see being welded in this thread.


This is my understanding.  Would be surprised if there are any production aircraft being gas welded.  I'm an aircraft mechanic by trade, and have patched up a few old rag and tube aircraft in the past.  Typical tube would be around 3/4" OD and .049 wall.  It varies a little of course, and does get a little larger and thicker in the landing gear area, but is generally surprisingly light.

It is amazing what can be gas welded with the right flux.  I have personally gas welded aluminum, though I found it quite difficult, as the metal gives little indication it has melted.  I'm pretty sure stainless, inconel, and other exotic materials were gas welded back in the day.


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## erikmannie (Jan 3, 2023)

paradox_pete said:


> This is my understanding.  Would be surprised if there are any production aircraft being gas welded.  I'm an aircraft mechanic by trade, and have patched up a few old rag and tube aircraft in the past.  Typical tube would be around 3/4" OD and .049 wall.  It varies a little of course, and does get a little larger and thicker in the landing gear area, but is generally surprisingly light.
> 
> It is amazing what can be gas welded with the right flux.  I have personally gas welded aluminum, though I found it quite difficult, as the metal gives little indication it has melted.  I'm pretty sure stainless, inconel, and other exotic materials were gas welded back in the day.



I am interested to get some flux for gas welding on aluminum, & I will be trying that soon in this thread. So far I have only found these offerings for an appropriate flux:






						Forney Alum-a-Flux Jar 4 oz.
					

Helps keep oxides from forming during welding and is a cleaning agent for the molten rod. 1/4 Lbs. (7.09g).




					www.littlehardware.com
				




and









						Aluminum Welding Flux
					

TM Technologies: Tools, Sheet Metal Shaping Machines, Gas Welding Supplies, Articles & lWorkshops for Better Metalworking



					www.tinmantech.com
				




I failed to link to eBay, but here is a screenshot:




Regarding not seeing the puddle in aluminum while gas welding, isn’t this the same as not seeing the puddle in aluminum while TIG welding?

By the way, this is why I prefer TIG welding on steel rather than on aluminum because of not being able to see the keyhole. I only choose aluminum when steel will not suit the application.

Honestly, I find steel to be very user friendly, but I have yet to warm up to aluminum as a material for welding.

We are lucky to have TIG as an option for welding aluminum, as the aluminum stick welding electrodes are a challenge (although once the base material is warmed up they will function).


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## cwilliamrose (Jan 3, 2023)

erikmannie said:


> Regarding not seeing the puddle in aluminum while gas welding, isn’t this the same as not seeing the puddle in aluminum while TIG welding?


There is a glare from the flux that makes seeing the puddle very difficult. Kent White sells some blue goggles for gas welding aluminum that everyone seems to like. I like his flux, which you linked above, and have used it (very sparingly) while TIG welding AL to shield the back side of the weld. That technique has some other benefits too but there's that same glare to deal with.  Haven't tried gas welding AL yet since I don't have good goggles.


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## cwilliamrose (Jan 3, 2023)

Here's a bit of screwing around I did to see what I could get away with using the Tinman's Premium Flux with TIG. I found the puddle stayed together even when it got stupidly large. Without flux it would have hit the floor at less than half the size. And the back side of the weld knitted together very well.

The upper image is the torch side of the weld, the bottom image is the back side. There are two welds here both heading toward the center of the panel. The first one (on the left) got really wide and started to sink, the second one got even wider as I really leaned on the pedal and the puddle only collapsed when I got close to the end of the first bead (something I've seen happen near tacks as well but I don't understand why).




If you guys play with this at home, use a very thin coat of flux on the back side only -- so thin as to be almost invisible......


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## Charles scozzari (Jan 3, 2023)

cwilliamrose said:


> Most aircraft 4130 welding is done with TIG these days. I used to gas weld 4130 but TIG spoils you. Some factory aircraft welding is done with MIG but that's not the norm. And most aircraft tubing is very thin compared to what you see being welded in this thread.


I know there is wire to use with a mig for 4130 and am wondering if anyone has used it. I also remember hearing a story of race car chassis that was mig welded and was then annealed in a large oven. I'm not to sure of that one, but who knows.


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## cwilliamrose (Jan 3, 2023)

I have never done MIG welding so I'm not the one to ask. I have used MIG wire for 4130 because you could buy a spool of small diameter weld wire for doing delicate parts.


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## Provincial (Jan 3, 2023)

In the olden days, aluminum welding flux had to be cleaned off thoroughly or it would cause corrosion.  I don't know if modern flux has that undesirable feature.


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## cwilliamrose (Jan 3, 2023)

You still have to rinse it off. I use a fine wire brush and some warm water.


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## Gaffer (Jan 5, 2023)

@erikmannie - I saw this video and thought of you.


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## G-ManBart (Jan 5, 2023)

erikmannie said:


> Regarding not seeing the puddle in aluminum while gas welding, *isn’t this the same as not seeing the puddle in aluminum while TIG welding*?
> 
> By the way, this is why I prefer TIG welding on steel rather than on aluminum because of not being able to see the keyhole. I only choose aluminum when steel will not suit the application.
> 
> ...


I hope not!  I definitely see the puddle when TIG welding aluminum.  I find it easy to see actually.  You should have a good puddle and each dab of the filler causes that spot to solidify as soon as you move past it.  That's how you get the nearly mirror finish beads...adding the filler freezes the puddle.  If it's a frosty finish it had too much time to cool and glazes over.

What often happens is people try welding aluminum like steel and do a couple of things wrong.  One, they ease into it on the peddle from the start which only gets the base metal hot.  You want to go full pedal to get a puddle in a max of 2-3 seconds (1 second is better) and then move fast...dab, move, dab, move with a purpose.  When people go too slow, or use too little heat, it winds up taking longer, which puts more heat into the work, and things start to melt and you get a big blob rather than a bead with a small puddle at the front.  It's sort of the opposite of steel in many ways...you're better having too many amps, and moving a bit too fast than the other way around.

I got one ten minute demonstration from a buddy and after that I spent 30-60 minutes almost daily for about two months practicing just running beads on coupons until I got pretty comfortable with it.  The biggest challenge was probably learning to feed the filler wire fast enough.


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## rwm (Jan 5, 2023)

Question about welding aircraft tubing? I was once told they were gas welded so the frame did not get magnetized and interfere with the compass. Is this a myth? Sounds like arc welding is now used?


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## G-ManBart (Jan 5, 2023)

rwm said:


> Question about welding aircraft tubing? I was once told they were gas welded so the frame did not get magnetized and interfere with the compass. Is this a myth? Sounds like arc welding is now used?


I don't know about the magnetic issue, but most chrome moly aircraft frames are definitely TIG welded now.  Some companies are using MIG, but they are using expensive machines with pulse functions, pre-heating the tubing and then proper annealing afterwards...along with having experienced welders who know what they're doing.

The nice thing about TIG welding is that if minimizes the heat affected zone (HAZ)  when done properly.  The HAZ is going to lose a certain amount of tensile strength, but with the right choice of filler rod (not 4130) the combination of the parent metal and the filler rod produces a more ductile weld bead so it doesn't crack.  Everything I've read about both aircraft and race car crashes and studying the damage says that tubing failures happen right where the tubing meets the HAZ if the welds were done properly.  Luckily, tubing for aircraft and race cars is thin enough that they can be TIG welded without the need for annealing afterwards.


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## Ultradog MN (Jan 6, 2023)

I still use ocy-acet for some things.
It is a simple and  inexpensive way to glue metal together and is rather portable.
I have a horizontal style exhaust pipe on my little Ford 3000 but it hung too low and I kept hitting the muffler on stuff. This fall I cut the exhaust pipe apart and raised it up about 3".
Gas welded it back together.
Looks kinda doohickey but serves my purposes much better now.


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## rwm (Jan 6, 2023)

Thanks Gaffer! After watching that video, I will likely give up welding....


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## Gaffer (Jan 6, 2023)

rwm said:


> Thanks Gaffer! After watching that video, I will likely give up welding....


LOL - yes. It was quite humbling!


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## erikmannie (Sunday at 3:03 AM)

I **highly recommend** this video on fillet brazing of this master brazer revealing his tricks!






It covers it all: flame, beautiful & patient brazing technique, braze washing, sanding, & even a destructive test at the end! He achieves both strength & beauty.

I have always been so critical of myself for often washing my welds, as well as grinding & sanding my weld beads. I know that you are expected to do this for brazing, but still, if you want the result to be both strong & beautiful maybe it is okay to wash & grind.


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## erikmannie (Sunday at 2:45 PM)

I will be practicing gas welding for the next few months (but only on the weekends). I am trying really hard to **not get into any other projects** other than welding on coupons.

Today I bumped up to a #4 welding nozzle for my 1/8” sheet coupons. I started off with a #2 (nowhere near enough heat), & then I tried a #3. 

I could get it done with the #3, but the work was going way too slow for me. Not many people would have continued on with a #3.

It sure was nice to finally have enough BTUs! I don’t mind gas welding if I have enough heat. Gas welding without enough BTUs is miserable & wastes time. 

With the #4, everything went fine. At times I had too much heat, but I just pulled away the torch.

I also switched to 1/8” R45 filler rod. You gotta love it when the diameter of your rod matches the thickness of your base metal.

Here is the first flat T-joint with the #4 welding nozzle, 1/8” rod, 10psi max oxygen & 7psi max acetylene. This weld has been washed, but only to get the toe of the weld to tie in to the parent metal. This weld bead is ugly but sound, has some cold lap, some undercut, and overfill.







Here is my stripping setup. I only weld on mill scale if I have to.


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## erikmannie (Sunday at 3:09 PM)

I will take some pictures of my setup. I invite constructive criticism because this is the setup that I will be using for months. 

Usually when you set up for something, it is only for one task. It was really nice to spend spend time setting up, & then not have to spend time setting up for months.

Ready for horizontal tack welds:



I am getting my money’s worth out of that stick welding glove by cutting off the burnt fingertips & wearing TIG gloves underneath it. The striker for the torch fits nicely in that pipe (dumb luck):









Jack is usually here:


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## erikmannie (Sunday at 5:07 PM)

Here are some more pictures. On the last joint, the toe of the weld tied in to the coupon at every point along the pass.

I certainly had enough heat. I might go back to a #3 tip with the maximum recommended pressure settings, because I was often in danger of getting undercut with the #4 nozzle. For .125” sheet, you are either going to use a #3 tip turned up really high, or a number #4 tip turned down really low.

I did wash this bead, but only down the centerline for the purpose of assured penetration.













I think this bead is unattractive yet sound, with some cold lap & some undercut. It has about the right amount of fill.

I have always preferred welding as hot as possible, if for no other reason than to complete the work quickly. Also, it is more exciting that way. You know you are welding too hot when you are almost getting undercut.


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