fuselage welding

[BJC]

Sounds like 7014

Having come from an electric utility with many highly competent welders, I designed a structural steel component for a process plant and specified 8016 rods. The top welder there came to me and asked me to redesign the weld for 7014 rods. They were reasonably competent with 7014, but had a difficult time making a good weld with 8016. He said, “Anyone can lay down a decent weld with 7014.”


BJC (Guess I did find something new to say.)

 

[proppastie]

redesign the weld

What was the difference in the design?

 

[TFF]

Arc welding with all the different types of rods is very complicated. Way more complicated than our simple 4130 with two to three different types of rods depending on your welding understanding on the joint, and most of that is a semantics. Some arc rods you can’t go uphill. Some you can’t go down hill or overhead. Different strengths and hardness properties, different ways the puddles lay. All outside out 4130 fuselage universe. The whole point of 4130 is no voodoo, no magic, no one up. If your trying to be different with 4130, you are building with the wrong material.

 

[BJC]

What was the difference in the design?

More weld area to achieve the same strength.


BJC

 

[Lauren Williams]

Having come from an electric utility with many highly competent welders, I designed a structural steel component for a process plant and specified 8016 rods. The top welder there came to me and asked me to redesign the weld for 7014 rods. They were reasonably competent with 7014, but had a difficult time making a good weld with 8016. He said, “Anyone can lay down a decent weld with 7014.”


BJC (Guess I did find something new to say.)

Yup, 7014, a low hydrogen, self chipping, drag rod. Just don't try to ues it overhead. No use in aircraft.

 

[Pilot-34]

my favorite thing about stick welding is when I pause to put a new rod in the holder and look back up the weld and see the flux peeling off all by itself,shiny new bead

My favorite thing about the stick is how it will do the welding job by itself if everything is dialed in right so you can turn it loose. Step around the corner take a whiz start a new stick and go grab a Coke out of the cooler.

 

[Steve Py]

I can oxy weld and was a D17 cert tig welder. Nothing wrong with oxy welding but tig is the way to go. Relatively easier, cleaner and less HAZ, which is important.

 

[wsimpso1]

You guys keep acting like there is a need for "better" in our tube structures for our little airplanes. Let's get some details out there:

• Yes, if I was running a business, trying to make money, and PAYING journeyman welders to put beads on metal, I would pick TIG over OA most of the time. Why? Because the journeyman welder will put on more feet of high quality weld a day and per dollar spent. The journeyman welder is usually the most expensive thing in the process, so make good use of that skilled staff;
• And if I were building plumbing for powerplants and nuke reactors, yeah a lot of it would be TIG. This ain't powerplants and nuke reactors;
• Most of us are building an airplane for entertainment and education. I contend that your airplane will be every bit as sturdy, entertaining, educational, and for less money with OA. If you just gotta spend $3-4k on a TIG welder and more per hour to operate it, go ahead. Mostly, in our airplanes, TIG is just spending more money than if you built in OA;
• OA was used since the 1930's with complete faith, is still the factory method for Bearhawk, Pitts-12, and last I heard Aviat (Pitts & Husky) were still all being produced with OA;
• The heat affected zone in 4130 matters not at all, as it is normalized by heating and aircooling. Annealled and normalized 4130 has about the same strength. Look it up if you do not believe me. Normalized used to be available, now annealled is what you can buy. And whatever amount of it gets hot and then air cools comes right back to where it started. Not worse - same;
• Most of the tubes in our airplanes are chosen by the designers to have margin for buckling and crippling when under the compression side of the load cases. That means the tubes and welds are usually substantially oversized for the other loading conditions and failure modes. Any weld that had good melt at the leading edge of the puddle and a decent bead is has excess strength and will give great life. How that melt at the leading edge and bead was achieved does not matter to 4130 welded with mild steel rod.

So, do you want another thing in your shop and another set of skills to learn enough to spend another pile of money on it? Then go ahead. Miller can use the business. But please do not believe nor boast that your airplane is stronger/more durable/more crashworthy/better because you spent more on welding it up. It is more expensive and may look nicer before you sandblast and paint it. But after you paint it, it is no better than the great airplanes that fill the EAA and Smithsonian exhibits.

Billski

 

[john87]

Yup, 7014, a low hydrogen, self chipping, drag rod. Just don't try to ues it overhead. No use in aircraft.

7014 is definitely NOT a low hydrogen rod..

john.

 

[Lauren Williams]

7014 is definitely NOT a low hydrogen rod..

john.

Gee, I've been misinformed (40 years ago). That's what I get for listening to fellow workers without researching it myself. Tim Mahone, dear fellow (RIP) you got me in trouble.

 

[al m]

This is thread drift, for OP didn't ask about laser welding.

I know I shall get banter for this (and deservedly so), but I only read Ch 3 of the attached book, which is on laser welding (which looks terribly easy to me, as a lay person, when I watch internet videos about it).

Anyway, I think the book is an interesting resource, and very well written, and might be worth the purchase for folks seeking answers in a thread like this. It's Welding And Joining Of Aerospace Materials edited by Mahesh Chaturvedi, and published by some folks at Duxford in the UK. If anyone needs a steer, send me a Direct Message.


Also, I have not read the American Welding Society's guidance, but if anyone has and if it says anything about laser welding do let me know; I'd be curious to read it.

https://pubs.aws.org/p/1754/d171d17...for-fusion-welding-for-aerospace-applications

---
- I feel I should add that I like mass-produceable light aircraft designs, hence my desire to understand what (if any) potential exists within a welding technique that might have advantages over others when used on the end of a robot arm, or might have advantages over other techniques if production had to occur in a location where skilled welders were hard or impossible to find.
- I'm aware that the starting price for the kit is $6k (Chinese) to $12k (European), and that will exclude it from outright purchase by homebuilders.
- I'm aware that the robot would have to be scratch-developed, and that tubular space-frames are not the 'best' way to mass produce light aircraft.
- my interest is so speculative as to be bordering on the academic. I'm not at risk of welding anything myself, any time soon.
- I haven't bothered to make a thread for laser welding in homebuilt aircraft because, for the reasons described above, it would probably be. a bit silly.

 

[TFF]

The real laser stuff costs a lot of money, and that makes about two people who would buy one for building 4130 fuselages. No matter what, you can’t get a machine to do this job and take up your slack. It’s a simple skill to learn. If you bought a laser set up, you will still make the same mistakes if you don’t learn how to weld.

 

[al m]

The real laser stuff costs a lot of money, and that makes about two people who would buy one for building 4130 fuselages. No matter what, you can’t get a machine to do this job and take up your slack. It’s a simple skill to learn. If you bought a laser set up, you will still make the same mistakes if you don’t learn how to weld.

Fair one - thank you. The conclusion I've come to is that the welding is the part of manufacture that most needs to be outsourced to an experienced party. I'm just always keen to be proven wrong

 

[Pops]

Having come from an electric utility with many highly competent welders, I designed a structural steel component for a process plant and specified 8016 rods. The top welder there came to me and asked me to redesign the weld for 7014 rods. They were reasonably competent with 7014, but had a difficult time making a good weld with 8016. He said, “Anyone can lay down a decent weld with 7014.”


BJC (Guess I did find something new to say.)

He was right. 7014 is easy and 8016 is hard. I have welded the top roof plates on the coal fired boiler. Using 7014, welding the heavy steel plate flat down you can fill the V with one pass and the slag with peel up and fall off behind the puddle. I would prop the stinger up just right and the rod would feed itself and make a perfect weld. I set on the 5 gal bucket and watch it burn and change rods when needed.

 

[BJC]

Fair one - thank you. The conclusion I've come to is that the welding is the part of manufacture that most needs to be outsourced to an experienced party. I'm just always keen to be proven wrong

Thousands of 4130 fuselages have been welded, successfully, by total amateurs. If you have fairly steady hands, it is straight forward to learn. One could be welding on an airplane very quickly.


BJC

 

[BJC]

I would prop the stinger up just right and the rod would feed itself and make a perfect weld.

When I first started working in a power plant as a co-op student, I snuck off to the fab shop and asked a welder to show me how to stick weld. He said, “There’s nothing to it” and did exactly what you just described, Pops.

The high energy pipe welding is interesting to see, but what impressed me was maintenance welding of 7/8” OD water wall tube with a working pressure in the range of 4,000 PSI. Done with two welders using OA, one on the inside of the furnace, sitting in a sling, and the other on the outside. One starts the weld, goes half way around the tube, then the other picks it up, and continues around and back to the first. Takes two good welders. No backing ring, but an almost perfect fit-up.


BJC

 

[TFF]

A friend welded food grade, building two dairies. The inside of the pipe had to be as smooth inside as outside to not hold bacteria. No way to reach inside to dress it, it just had to be perfect. He was most known for welding refrigeration plants when blocks of ice were still everywhere. There use to be a company local where they made nuclear heat exchangers. They had a bunch of good welders until it closed.

Everyone seems to want to be dainty. Starting to learn to weld is a bit like trying to cross a muddy bank next to water. At first you tip toe around trying not to get dirty. At some point you have to accept it’s going to come up to your knees, so you might as well get on with it. Once past it, it’s not bad.

 

[Pops]

When I first started working in a power plant as a co-op student, I snuck off to the fab shop and asked a welder to show me how to stick weld. He said, “There’s nothing to it” and did exactly what you just described, Pops.

The high energy pipe welding is interesting to see, but what impressed me was maintenance welding of 7/8” OD water wall tube with a working pressure in the range of 4,000 PSI. Done with two welders using OA, one on the inside of the furnace, sitting in a sling, and the other on the outside. One starts the weld, goes half way around the tube, then the other picks it up, and continues around and back to the first. Takes two good welders. No backing ring, but an almost perfect fit-up.


BJC

Did that many years. I was usually the one on the inside in the sling.
Some boilers has 8" supply tubes to the wall tubes where you have to be lowered down in a cluster of tubes in a harness and the space is so small that another helper has to hang upside down and reach down and put the welding rod in your stinger and bend it the way you want and you weld your half and the welder on the other side picks up your welding puddle and does his side. No room for a welding helmet , you wear a welding sock over your head. You have about 3" in front of your face.

 

[BJC]

you have to be lowered down in a cluster of tubes in a harness

Yup, been in the space in a 560 MW generator, between the outer shell and the outside of the iron laminations. Took a long time to wiggle in; had to have someone half way in behind me pull me out by my feet. I was skinny back then. Wouldn’t do it again; would cut the shell, do the work, then weld it up. Inside of the top of a deaerator is another space where being claustrophobic would be a major impediment.

Watched a steel worker free “monkey walk” up a 40 foot vertical H section (probably > 200 lbs/ ft) then stand on top and light a cigarette, waiting for the crane to lift a horizontal brace. All about 250’ in the air with no fall protection. Glad that there were people like you to do that, Pops, because if it had been up to me to do, it wouldn’t have happened. Then OSHA was created, and lots of things changed.

16 people died constructing, operating and maintaining that power plant. (Southern Company / Georgia Power Company, Plant Harley Branch) I would have been with three of them - steel erectors - if I had not had to leave the construction area and go to a safety meeting. Yup, a safety meeting literally saved my life.


BJC

 

[al m]

Thousands of 4130 fuselages have been welded, successfully, by total amateurs. If you have fairly steady hands, it is straight forward to learn. One could be welding on an airplane very quickly.


BJC

Thank you!