Welding help, legal question.

[Mcstealth]

Hey guys (and girls).  Questions please. 

Here is a picture of a crack in the motor mount of the Darter I am flying. It is in the shop for the 100hr.  First question is can this crack be welded on site? It doesn't look all that complicated of a procedure to me, the untrained eye. Do we have to remove the mount to weld it?  

Second question is what are the legalities surrounding this kind of repiar?

Next question is should we remove the engine and replace the motor mounts while we are waiting on the cylinders? Makes sense to me. 

Thanks for all the help, past and present. 

David

 

[A64Pilot]

If it can be assessed, it can be welded in place. I’d recommend TIG although gas is allowable.

There is some danger possibly to your alternator and starter or anything the electrical flow could go through, but if the ground is placed right near the crack it shouldn’t be an issue. I’ve seen a few welds done with a turbine in place with no issue.

Most conservative answer is to remove the mount, have it bead blasted, inspected and repaired.

I happen to know where that mount was built and am surprised to see the crack, that place has a very good rep for tube structure.

Legal wise repair IAW AC 43.13

Of course have someone standby with a fire extinguisher in hand just in case.

Edited June 2, 2022 by A64Pilot

[GeeBee]

It can be repaired, and there are a number of shops that do. Acorn, Aerospace Welding in MSP, Loree in CA. It is best to remove the mount and send it off as the repair station will want to make sure the mount is true as well as check for other areas of corrosion or defect. Do not weld it while in place. One it is difficult to make sure it is true and as mentioned, you can create all kinds of unwanted magnetic effects. You want a repair station to do this work so it comes back with paper.

 

[midlifeflyer]

The "legalities" consist of "approved" or "acceptable" data for major repairs. Best source is https://www.faa.gov/documentlibrary/media/advisory_circular/ac_43-210a.pdf

[EricJ]

An A&P can supervise a reputable welding shop (any shop) to do the repair, or do it themself.    That's legal.  There's a section in AC43.13 on welding repairs for tube structures.

That said, especially if the airplane is down for maintenance anyway, it's a good idea to remove it and take it someplace knowledgable about such things, like the places listed above.   Rewelding over an area already welded can be tricky, and preventing distortion, maintaining heat control, etc., is best done off the aircraft in a jig.

If it is at all practical I'd get it to somebody reputable for aircraft, and particularly motor mount, repairs.

 

[Mcstealth]

On 6/2/2022 at 2:30 PM, A64Pilot said:

 

I happen to know where that mount was built and am surprised to see the crack, that place has a very good rep 

The shop that built this still in operation? For the Darter 100?

Please advise. 

[Mcstealth]

On 6/2/2022 at 2:30 PM, A64Pilot said:

 

I happen to know where that mount was built and am surprised to see the crack, that place has a very good rep 

The shop that built this is still in operation? For the Darter 100?

Please advise. 

Edited June 4, 2022 by Mcstealth

[Fly Boomer]

1 minute ago, Mcstealth said:

The shop that built this is still in operation? For the Darter 100?

Please advise. 

 

[carusoam]

Having the mount in place with the engine on it….

Is going to add to the variability of things…

Welding stress in place… or getting the crack to close up properly before welding the gap in place…

+1 for sending to a proper shop…. Gets all of the wonder ifs out of the way…

 

PP guesses only…

Go darter!

Best regards,

-a-

[A64Pilot]

2 hours ago, Fly Boomer said:

 

It was built at the Aero Commander plant in Albany Ga., they built several GA aircraft there but have only built the Thrush Crop Duster for several decades.

They built the Meyer’s 200 there which is more of a tube steel structure than a Mooney and is about the only airframe that can brag it’s never had an AD, Aircraft that came from that plant have a rep of being overbuilt but also not being the lightest in their class.

Harold Kosola ran a shop in Albany that would have had a Jig most likely for the motor mount, but I think finding a Jig isn't likely to happen, last I heard Harold closed the doors years ago. Shop was Kosola Associates. Harold had a Jig for pretty much anything that was built just down the road.

Apparently AWI acquired Harold’s shop and maybe has a Jig. Unless several tubes need replacing I don’t think a Jig is necessary

https://awi-ami.com/awi-acquires-kosola-and-associates

Thrush can’t help you though.

Pic of where your aircraft was born, I don’t think they were built anywhere else, but aren’t certain

 

Edited June 4, 2022 by A64Pilot

[Mcstealth]

Hey guys, and girls. Still need to get this motor mount welded. Specialized Aero in San Marcos states they can do it, but have asked me specifically what kind of metal tubing it is. How do I find out that answer?

[carusoam]

MS has a metallurgist… that may be able to say how it can be done in the field….

If you have access to its parts and service manuals… it probably gives ideas there…

Check with engine mount builder companies… see if they are all made of the same steel tubing…

PP guesses only…

Best regards,

-a-

[M20F]

7 hours ago, Mcstealth said:

Hey guys, and girls. Still need to get this motor mount welded. Specialized Aero in San Marcos states they can do it, but have asked me specifically what kind of metal tubing it is. How do I find out that answer?

If they are asking this question, probably not the people you want welding it.  I would go with Acorn, Aerospace Welding that @GeeBee recommends my experience has been positive. 

[Mcstealth]

13 hours ago, M20F said:

If they are asking this question, probably not the people you want welding it.  I would go with Acorn, Aerospace Welding that @GeeBee recommends my experience has been positive. 

That's not it. They said it was most likely 4130 chrome molly (sp?) But wanted to know if I knew specifically. 

I will have my hands on all the logs and books later today so hopefully I will find something out. 

[M20F]

15 minutes ago, Mcstealth said:

That's not it. They said it was most likely 4130 chrome molly (sp?) But wanted to know if I knew specifically. 

I will have my hands on all the logs and books later today so hopefully I will find something out. 

I wish you the best of luck.  You got some pretty solid feedback by knowledgeable folks.  How you proceed is your decision.  

[Pinecone]

I doubt that will be in the logbook.  4130 is a good bet, although older aircraft did use other grades.

From my training, I would probably weld it with ER80S

 

USA 80S-D2 is designed to give high strength weld son high sulfur bearing (free-machining) steels or medium carbon steels. This wire contains additional amounts of manganese and silicon which, when alloyed with 0.50% molybdenum, produces weld deposits which have high ductility, excellent impact values and tensile strengths of approximately 100,000 psi. USA 80S-D2 is commonly used on low carbon and low alloy steels such as AISI 4130 where tensile strengths provided by plain carbon steel wires are inadequate. A well balanced silicon content gives this wire superior arc stability, a low spatter level and a flat bead with excellent appearance. USA 80S-D2 produces X-ray quality, porosity free welds even over dirt, rust or mill scale.

Applications:
Farm implements, automotive parts, pipes, light-gauge steels, low alloy steels such as AISI 4130 and high yield steels such as T-1.

[EricJ]

1 hour ago, Mcstealth said:

That's not it. They said it was most likely 4130 chrome molly (sp?) But wanted to know if I knew specifically. 

I will have my hands on all the logs and books later today so hopefully I will find something out. 

The SM for M20J says the fuselage and landing gear tubing is 4130 chrome moly.   The engine mount is not described, strangely, doesn't even have a diagram, but I agree is likely 4130 CM.

 

[Mcstealth]

2 hours ago, M20F said:

I wish you the best of luck.  You got some pretty solid feedback by knowledgeable folks.  How you proceed is your decision.  

Fully agree. 

[Mcstealth]

20 hours ago, Pinecone said:

I doubt that will be in the logbook.  4130 is a good bet, although older aircraft did use other grades.

From my training, I would probably weld it with ER80S

 

USA 80S-D2 is designed to give high strength weld son high sulfur bearing (free-machining) steels or medium carbon steels. This wire contains additional amounts of manganese and silicon which, when alloyed with 0.50% molybdenum, produces weld deposits which have high ductility, excellent impact values and tensile strengths of approximately 100,000 psi. USA 80S-D2 is commonly used on low carbon and low alloy steels such as AISI 4130 where tensile strengths provided by plain carbon steel wires are inadequate. A well balanced silicon content gives this wire superior arc stability, a low spatter level and a flat bead with excellent appearance. USA 80S-D2 produces X-ray quality, porosity free welds even over dirt, rust or mill scale.

Applications:
Farm implements, automotive parts, pipes, light-gauge steels, low alloy steels such as AISI 4130 and high yield steels such as T-1.

Thank you for the specific detail. Of course, you could secretly be trying to give me Nuke codes, and I would miss it.

[A64Pilot]

On 8/22/2022 at 12:06 PM, Mcstealth said:

That's not it. They said it was most likely 4130 chrome molly (sp?) But wanted to know if I knew specifically. 

I will have my hands on all the logs and books later today so hopefully I will find something out. 

If it was built in Albany and I’m nearly certain it was, it’s 4130 and was Tig welded