your opinion of this weld?

AirScooter

Scott Waggoner
Joined
Sep 27, 2009
Messages
870
Location
Bear Poplar, NC
Aircraft
Tandem Dominator-Zenith 701
Total Flight Time
8 minutes, 31 seconds
I think it looks like a gas problem, the weld looks granular for lack of a better word.
We build an atmosphere around titanium welds. Then the whole weld/part is in the inert gas, not just the face of the weld.
But I could be wrong.
 

AirScooter

Scott Waggoner
Joined
Sep 27, 2009
Messages
870
Location
Bear Poplar, NC
Aircraft
Tandem Dominator-Zenith 701
Total Flight Time
8 minutes, 31 seconds
Well, we may just be using different words for the same thing. To me, purging is done to a hollow member that is being welded. That could have been done here and it would have protected the interior wall of the square tubing from "sugaring". But it is hard to back purge that sheet stock or flat material that was welded to the tube. That is why we build boxes around the weld or put the whole thing in a big box. (visualize a blast cabinet filled with inert gas) In this exact situation we would have built the box and purged the tube honestly. We are in the industrial field not in aircraft building. That may not be done in building aircraft but it should be in my opinion, it is titanium after all. The problem could also be incorrect filler.
 

Hosko

Junior Member
Joined
Sep 29, 2014
Messages
145
Location
Narrabri
Aircraft
RU-X8 Rotor Ute
Total Flight Time
1000
Is this the Titanium gyro .. as in a production machine? Wouldn't ASRA have looked at this weld and made a determination if they wanted to release a directive?
Yes , TAG gyroplane . The faulty weld wasn't investigated.
The weld has a number of faults - wrong temp , little penetration , brittle , may have been wrong shielding gas or wrong filler .
 

Attachments

  • 10787582-3x2-700x467.jpg
    10787582-3x2-700x467.jpg
    46.6 KB · Views: 26
  • 20210109_071948.jpg
    20210109_071948.jpg
    21.8 KB · Views: 26

Hosko

Junior Member
Joined
Sep 29, 2014
Messages
145
Location
Narrabri
Aircraft
RU-X8 Rotor Ute
Total Flight Time
1000
Well, we may just be using different words for the same thing. To me, purging is done to a hollow member that is being welded. That could have been done here and it would have protected the interior wall of the square tubing from "sugaring". But it is hard to back purge that sheet stock or flat material that was welded to the tube. That is why we build boxes around the weld or put the whole thing in a big box. (visualize a blast cabinet filled with inert gas) In this exact situation we would have built the box and purged the tube honestly. We are in the industrial field not in aircraft building. That may not be done in building aircraft but it should be in my opinion, it is titanium after all. The problem could also be incorrect filler.

Somebody emailed me this photo, of a gyro frame weld that cracked upon crash impact.
There are some very experienced welders on this forum, so I'm curious about their opinion on penetration, possible embrittlement, etc.
Thank you.


View attachment 1144556

P.S. Since it'll be asked, the metal is neither steel nor aluminum, but has atomic number 22.
Part of the same wreck.
 

Attachments

  • 20210109_164422.jpg
    20210109_164422.jpg
    121.1 KB · Views: 40
  • 20210109_164410.jpg
    20210109_164410.jpg
    92 KB · Views: 40

Hosko

Junior Member
Joined
Sep 29, 2014
Messages
145
Location
Narrabri
Aircraft
RU-X8 Rotor Ute
Total Flight Time
1000
A good penetrated weld should never break in the weld bead but right next to it. This is a cold one. I personally would design that plate differently so it's not so reliant on just welding. The weld "looks" good so it does get beautification marks but that's deceiving. What is this crack on exactly? I am not a welding expert hands-on but I have worked with good welders in the Apollo LSA which was all 4130 welded frame and Revo trike and now AR-1. I have had to document special process definitions for welding and this would qualify for a cold weld and also a badly designed weld area relying only on weld
Yes , poor design . The plate should never haver been welded in the centre of the rhs ..... the plate should have lengthened to reach the edge of rhs & welded along the edge.
 
Joined
Jun 7, 2019
Messages
96
Location
Bryan, Texas
Aircraft
Cessna 140, Stinson 108-1, Culver V, Parsons Trainer
Total Flight Time
1000 hours
Could be contamination if it is titanium. Cleaning the weld with too high content of chlorine in the water will cause brittleness at high temperature. Aluminum welds are never to be trusted. Vibration and aluminum welds don’t care for each other at all. Looking at the Union of the base metal to the weld, it does not look puffy or piled-on like a cold weld would be. Certainly that Union is not gouged like an overheat. It’s a pretty looking weld but as they say looks are skin deep. Wow, it’s shocking nonetheless.
 
Top