Welding Tips and Tricks

And after 2 or 3 dips of the filler....it puked all over the tungsten. Having already drilled a vent hole way out on the part to kill internal pressure I thought this couldn't be the case. Wrong again I was. There is a tube inside the outer tube after drilling a new hole closer to the repair area. Question is when the puddle blew out and the weld area cooled rapidly do you think the parts are now ruined? 4130 tube that has had a splice or stiffener installed. Or should I brush the blow out clean and fill it and motor on?

jumpinjackflash wrote:And after 2 or 3 dips of the filler....it puked all over the tungsten. Having already drilled a vent hole way out on the part to kill internal pressure I thought this couldn't be the case. Wrong again I was. There is a tube inside the outer tube after drilling a new hole closer to the repair area. Question is when the puddle blew out and the weld area cooled rapidly do you think the parts are now ruined? 4130 tube that has had a splice or stiffener installed. Or should I brush the blow out clean and fill it and motor on?

What's the part on or go to?

jumpinjackflash wrote:And after 2 or 3 dips of the filler....it puked all over the tungsten. Having already drilled a vent hole way out on the part to kill internal pressure I thought this couldn't be the case. Wrong again I was. There is a tube inside the outer tube after drilling a new hole closer to the repair area. Question is when the puddle blew out and the weld area cooled rapidly do you think the parts are now ruined? 4130 tube that has had a splice or stiffener installed. Or should I brush the blow out clean and fill it and motor on?

If this is an airframe, I'd consider carefully how to fix it. How tight was the fit between the tubes? Could the progression of heat up the inner sleeve swelled it to block the exit path for expanding air? Did you have rosettes drilled outside of your splice that should have relieved this pressure?

I personally doubt that it's beyond repair, but we must get to the root cause (no pun intended) of the blow-out.

I'm going to dig a bit.

Steve S

Here's a screen shot of a properly designed splice, including the rosettes, that relieve pressure and are closed last.

https://www.dropbox.com/s/l22bpn0t66o6y ... 3.png?dl=0

Here's the very old (but still valuable) gov't film this comes from:

https://youtu.be/Sd3sw0OppWM

Steve S

Have to do almost the same thing when putting the outer jacket back on a cooker for the insulated cavity. When everything is real cool you go plug the holes one at a time to keep it from heating up and blowing out.

Its going to be replaced. After thinking about it ...its not worth the risk. Torque tube for a flight control '46 Aeronca . We have already ordered new tube and planning to do the job this weekend...calling for several inches of rain...perfect time to make things right. You wouldn't believe the layers of who knows what gets slathered on airplane parts through the years.
Thanks all ! I have told myself all the times like this....if in doubt-throw it out
A blow out like that meant in no way a slow taper off...not right=not safe. Our A&P- I/A agreed.

Yep, when in doubt toss it out.
35 years of working on aircraft and helicopters reinforces that, especially if your bum is in a seat for the test flight.
Murphy is a prick, always finds the thing thats "not quite right" and works from there.
Got any photos?