Fuselage Welding

[rail]

Re: Fuselage Welding

I apologize for creating the monster debate :boxing: on pre & post heat!

Charles Finch
Charles' Metal Shaping & Spinning

Re: Fuselage Welding

Yah Dave, that's one I'd like to hear the reasoning for as well....that and the reference to it being listed on the TC.... I'm still trying to figure that out... but not holding my breath.
John

Hi John,

All this is making my head hurt.

I am going to ignore this discussion from this point in time forward.

I am just going to follow Richard Finch and ac43.13. Finch is recognized welding expert and author. That carries more weight in my opinion.

Dave

[N96337]

Re: Fuselage Welding

Yah Dave, that's one I'd like to hear the reasoning for as well....that and the reference to it being listed on the TC.... I'm still trying to figure that out... but not holding my breath.
John

Re: Fuselage Welding

Hi Mark , I answered your direct e-mail , certified Taylorcraft repairs require Oxy-Acet . I It is up to your A&P and IA if he ( they) wants to deviate, when the weld fails and causes a death may be on the side of the deceased parties family . pre and post is correct. I always wonder why, just do it with the torch in the first place.

huh?

[Forrest Barber]

Re: Fuselage Welding

Stinson used electric arc welding way back then and had to do the oven bit.
We did an experimental ship here where they put the fuselage into an oven when it was done and it was an all aluminum riveted structure.
I don't think I pre heat , I merely bring all the surrounding tubes up to a temperature below the red that I am looking for, do the weld and then flame it all evenly ,then let it cool with NO drafts... DONE!
There are alot of ships out there done this way that are 70 years or better, even the correct popping a hole or holes into the interior of the cluster to allow inside oiling is an art .
Then if the tube is properly closed off, all oxygen is gone thus no rust in the sealed tube.

Re: Fuselage Welding

man, after reading all of this, i am going to stick with jb weld.....(;f

lol!

[rammon3]

Re: Fuselage Welding

Well, the choice is easy for me. I have owned a Smith's torch for the last 30+ years and can't afford a TIG outfit. So, it's gas for me.

[Ray36048]

Re: Fuselage Welding

Man, after reading all of this, I am going to stick with JB weld.....(;f

[flyguy]

Re: Fuselage Welding

This is way out of my area of knowledge, but Finch states that 1600 Aerostar tubular 4130 engine mounts were TIG welded without post or preheat and there is no recorded instance of failure or cracking.

It would be interesting to read any reports of extensive metallurgical and strength testing of TIG welds on 4130 with and without thermal stress relief after welding.

Darryl

Re: Fuselage Welding

Holly cow this is getting good!

I think everyone is getting a little too defencive about the welding process they use.

If you like Oxy-Ace and prefer it great! Its an FAA acceptable method of welding.

If you like Tig welding and prefer it great! Its an FAA acceptable method of welding.

The point with both of these methods of aircraft welding should be knowing how to use either of them properly. One method is not better then the other. Both methods can be done incorrectly with disastrous results.

I would like to see a little more constructive discussion about this topic.

What method do you use? Why do you prefer it?
What filler rod are you using? Why do you prefer it?
If Oxy what pressures are you running? Why?
If Tig what kind of Machine are you using and how do you have it sent up?
What problems or mistakes have you made?
If heat treating how are you gauging temps?

I know i can Google and get the text book answers for all of these Questions but that is not what I'm after here. I have been welding for a while and I'm always interested in learning from other people. Lets help each other out here and not get into a pissing contest over who method is better.

Hi FK,

The "pissing contest" ensued because of the post from Forrest that equated the use of electric welding with the death of the aircraft occupants. That was bad and untrue and will unfortunately influence many.

I and many others use electric welding for aircraft work.

I have used one of those small Lincoln 125 amp/110v MIG machines for doing the straight weld on two sides of a sleeve repair. Also for flat plates when I repaired wing strut attach fittings. Actually I think that both wing struts on my tcraft and part of the upper cabin section may be help on partiallty by mig welds. I had no success using it for curved joints like scarfs or fish mouths. Some folks can do it but I can't. The wire squirts out faster than I can move around the compound curves.

I now have a 255 amp mig machine but I find it difficult to use for even the straight welds I mentioned above. The 255 amp supply will pump out a lot of current and I don't like that on thin material, it can burn through. I wish that I had kept my 125 amp machine (both are/were Lincolns, red).

I don't use my gas set up much in the last 10 years. What I didn't like about gas was the hot gas/air blow back when welding in "corners" and the lack of control of heat. I have a Smith airline set up.

My favorite is my Miller Dynasty 200 dx (blue). I has every bell & whistle I can think of, I only use a few, a waste of money I suppose.

For all the a/c tube work I set the max amp at about 90-100 but I have thumb wheel on the torch so the actual amperage is adjusted as needed. Most often I use the ER70s-2 (same as AWS A5.18 in ac43.13-1b table 4-15)wire or rod .035 dia. Basically the same for TIG and MIG but one is on a roll. On some field approval repairs I did I had to use ER80d-d2 (same as AWS A5.28 in ac43.13-1b table 4-15) to make the bead meet some spec that I forgot now.

Usually 1/16 tungsten works well, I found that .040 is hard to use and maintain, it gets too hot and deforms (could be me). Usually I use thoriated or ceriated which ever I pick up first.

With all the TIG bells and whistles I end up only occasionally using the dc pulser and the ac freq control.

I like the pulser for heat control and it makes pretty beads, more or less it helps prevent me from making welds too hot and enforces a cool off period. Or it just may make me feel better. When I was repairing some wing struts about 10-15 years ago a welding engineer whom I consulted told me I should use TIG with a pulser on them. I got a TIG at that time but could not afford the pulser. The struts came out fine. A few years after that I was able to afford this machine but I find that one can do as well without the pulser as with it, but it just takes more effort. That's what I think.

I have found that the AC freq control, ie. setting say to 200 hz forces a narrow arc and bead on aluminum.

Dave.

[astjp2]

Re: Fuselage Welding

[/COLOR]

Please explain???

The filler rod is typically larger and you can fill larger gaps easier from my experience. I have seen gaps of 3/16" filled on a piece of .035 tube and it looked ok and had good penetration.

[FAT KID]

Re: Fuselage Welding

Holly cow this is getting good!

I think everyone is getting a little too defencive about the welding process they use.

If you like Oxy-Ace and prefer it great! Its an FAA acceptable method of welding.

If you like Tig welding and prefer it great! Its an FAA acceptable method of welding.

The point with both of these methods of aircraft welding should be knowing how to use either of them properly. One method is not better then the other. Both methods can be done incorrectly with disastrous results.

I would like to see a little more constructive discussion about this topic.

What method do you use? Why do you prefer it?
What filler rod are you using? Why do you prefer it?
If Oxy what pressures are you running? Why?
If Tig what kind of Machine are you using and how do you have it sent up?
What problems or mistakes have you made?
If heat treating how are you gauging temps?

I know i can Google and get the text book answers for all of these Questions but that is not what I'm after here. I have been welding for a while and I'm always interested in learning from other people. Lets help each other out here and not get into a pissing contest over who method is better.

[rail]

Re: Fuselage Welding

Pre and post heat for tig, I would rather gas, less requirement for tight fitment of the joints. Tim

Please explain???

[rail]

Re: Fuselage Welding

Boeing actually welded aluminum with a torch Oxy/Hydrogen until 1996 when the flux was considered toxic and not cost effective. Go look at the tin mans website, what he can do with a torch is amazing on Aluminum.

Dave, It used to be there, but with all things FAA, it might have fell by the wayside. I need to find my copy of cam 18 and see what it says. I have a friend that teaches high school and university aircraft welding and he told me to pre and post heat too. It seems that depending on what expert you talk to, will give you thier version....

Aluminum pressure vessel fitting specimen before cleaning! Sectioned for penetration inspection. TIG process!

[astjp2]

Re: Fuselage Welding

What is the size of the HAZ of tig compared to Torch?


The base material and filler material melt at the same temps with Tig or gas.