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Weld or Braze?

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Protech Racing

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The race cars that I worked on are all brazed, very little or no welding. I welded my last 4130 fuse together. But wonder if I can braze some of the diagonals for the rear of the Demoiselle fuse . I plan on gas welding the majors .
 

cluttonfred

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Brazing of mild steel tubing was used on some early homebuilts of the 1920s and 1930s but seems to have been abandoned once welding became widely available. Why experiment with brazing if you are going to be using welding anyway?
 

Protech Racing

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Is the full 4130 fuse then normalized?
I usually normalize the entire area , maybe the entire nose section that the engine will shake.
Brazing can be a lot faster but a little tiny bit heavier .
 

Protech Racing

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Thanks . Kinda what I thought. Both can work fine.
Whats the best source for RG65 welding rod? Some oldtimer told me thats all that you should use for 4130 .
 

Alister Sladen

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I worked in the Racecar industry for many years and race cars haven't been brazed for many decades as its a much slower process than TIG welding and there is less control of the heating than with a TIG or MIG. Also the flux used also needs to be removed after Brazing even when using Vapourflux. I'd also suggest that Oxy Acetelyne welding isn't the solution for 4130 tube thin wall welding. I've seen an aircraft frame repair that had to be cut out and replaced with new tubes due to the amount of heat used distorting the weld area.

Also as far as normalizing after welding that Shouldn't be done in my opinion as the 4130 tube is supplied in a 'Condition N' and adding large amounts of heat will reduce the strength of the tubing.

BTW High end 'Steel' bike frames are generally brazed due to the very high tensile tubes used that have high Manganese levels.
 

TFF

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4130 was invented for Oxy acetylene. Because someone tried to weld some tube with a torch that a dock worker would use is not quite apple to apple. There would be no Piper Cubs if you couldn’t weld with OA.
 

Alister Sladen

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4130 was invented for Oxy acetylene. Because someone tried to weld some tube with a torch that a dock worker would use is not quite apple to apple. There would be no Piper Cubs if you couldn’t weld with OA.
Yes I understand what used to be the norm, I brazed up my first 4130 frame back in the early 80's with Nickle bronze wire and Vapourflux. Gas welding using a wire filler was not ever an acceptable option and now 40 years later Industry best practise is to Tig weld. See if you can find a Company producing Club's made in the last 20 years that were 'Gas welded' or even brazed. Just because someone did it before doesn't mean it was the best option, Tig welding was the accepted best option in the 90's.
 

TFF

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Although I have TIG I am 50/50. Sometimes I do both. I don’t care about show beads. I’m about easy. There hasn’t been made the same number of Cubs in the last twenty as the first 60. Lots of homebuilts are being made OA. On the Biplane forum a Charger is going right now OA. Lots of traditional homebuilts are still OA while shops use TIG. If you got the practice and machine, cool.

I know stuff like Formula Fords and up have been brazed since the 60s. Just not done normally in aviation. The beauty though at least in the US is if you want, you can. You are just not going to get a consensus.
 

wsimpso1

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Hmm, so
I worked in the Racecar industry for many years and race cars haven't been brazed for many decades as its a much slower process than TIG welding and there is less control of the heating than with a TIG or MIG. Also the flux used also needs to be removed after Brazing even when using Vapourflux.
All true.

I'd also suggest that Oxy Acetelyne welding isn't the solution for 4130 tube thin wall welding. I've seen an aircraft frame repair that had to be cut out and replaced with new tubes due to the amount of heat used distorting the weld area.
Gotta dispute this. 4130 and gas welding have been making strong durable airplane fuselages and assemblies for longer than just about all of the folks on this forum have been alive. Museums and airport hangars are loaded with airplanes built this way. An anecdote on one poorly done repair does not make the process unsuitable. There are benefits to both with the whole TIG vs OA argument covered well on the above mentioned threads...

Also as far as normalizing after welding that Shouldn't be done in my opinion as the 4130 tube is supplied in a 'Condition N' and adding large amounts of heat will reduce the strength of the tubing.
Gotta dispute this too. Condition N IS Normalized tube, which is also about what happens when you gas weld an assembly. That is one of the beauties of 4130. Material strength is not changed by welding it.


BTW High end 'Steel' bike frames are generally brazed due to the very high tensile tubes used that have high Manganese levels.
We are not talking double butted tubes in bikes here. This is a forum on homebuilt airplane tube structures, and they are made of straight 4130 tubes. The load condition that usually ends up setting the tube sizes are resistance to buckling and crippling under compressive load, which is dominated not by yield strength but by cross section I times the elastic modulus of steel - a pretty much fixed number for all steels.

Billski
 

wsimpso1

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Moderator Mode is On

This thread was started on the whole Braze or Weld idea, something covered elsewhere in these forums, and those are great places to soak up all of the already existing posts contributed on the topic. Please use the Advanced Search tool to find established threads on any topic before starting the discussion over...

This thread was not started on how to weld. Please go to the already established threads to discuss MIG vs TIG vs OA and soak up all of the already existing posts that contributed on that topic. If you can contribute something new in those threads, have at it.

Re-Starting any worn out and tired topic anew and as thread drift is not good for the forum or for our collective knowledge on what works. Please use the Advanced Search tool to find threads already in existence on topics before starting your own thread. The reason is simple. Many different threads on the same topic just dilutes each one AND makes finding meaningful discussions more difficult.

This forum is about building and maintaining home built airplanes. While we understand that borrowing knowledge from hobbies and shops in other industries might have value, let's remember that if the other area converged on one technology and homebuilt airplanes converged on another, there might be darned good reasons for them diverging. Please discuss those reasons on those threads.

Last, let's keep the personal attacks out of our posts. Some above tread the line, and repeats will get Moderator actions.

Bill
 

MadProfessor8138

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Not to push my luck with the Moderator's warning but.......

See if you can find a Company producing Club's made in the last 20 years that were 'Gas welded' or even brazed.
A very close friend of mine,who passed away a few years ago,supplied Wag Aero with all of their cub frames and many components to the airframe.
He only used OA......"AND ONLY OA".
He produced airframes that were better than the factory originals .......and people would come from all over the country to have him build an airframe for them or do repairs.
The man was an artist and is sorely missed.....if I knew 1/4 of what he had forgotten,I would be building the frames in his place.
Sadly,he passed before I could obsorb all of the information he was capable of sharing.

So,yes....there is new equipment and new techniques....but the old ways are still quite viable.
After 1,000's of years of evolution....we still dig holes with shovels,don't we....because it works quite well.

Kevin
 
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