Couple years ago during a preflight I found some cracks in a tail fitting on my Luscombe. After talking with my A&P and doing a some research I found out the cracks were common and not a safety issue, so I have been flying like that for the past two years....I'm sure that raised some brows . There was a service bulletin on the bracket back in 1948 that addressed this part and what the problem was. The part had a corner that needed to be sanded into a .25" radius to allow for stress relief because of a manufacturing flaw. So I thought if I had the cracks welded it would both repair the damage and relieve the internal stresses which would be better that replacing the part with one that is just going to crack again.

So finally getting to my question....who can weld it? Does it have to be a PMA certified welder or can I have it welded by a guy I know who is a very good professional welder and have my A&P sign it off?

You want to do what now?

I would be careful with that approach.
First just welding the part doesn't necessarily relieve stress concentrations, more like moves them

Also Alloy steel parts must never be welded that have been hardened or treated.

For continued airworthiness the method of repair must be prepared by the manufacture, or acceptable to the administrator

If there is already a bulletin on the problem then welding it wouldn't seem to be using an acceptable method you may want to look at AC 43.13-1B 4-37 to 4-59 on up to 4-79

Go over this info with your IA as he is going to be the next one to sign off on it then you can decide how to proceed.

Your last answer is correct. Legally I believe the welder has to work under the supervision of an A&P I think, but most will of course inspect the weld and if it is acceptable, sign it off. Ask first though.
A manufacturer can manufacture, but not repair unless they also have a repair station, so a PMA may not be any good for you.
For whatever it's worth my opinion is that aircraft "stuff" should be TIG'd. Now that's an opinion and gas welding is perfectly acceptable on some metals, just I think TIG is better.
Welding by itself will probably build in stress, not relieve it. For that the part has to be stress relieved.

On non-aircraft equipment I have drilled a hole at the end of the crack to stop the crack from continuing, grind out the crack and fill with weld. If it is a hardened alloy, I have had good success with even cast iron, by using a copper-nickel alloy rod. And I agree with A64 that tig is the preferred method with much better control of the weld process. I have no idea if this would be an acceptable process for that part...you would have to ask a qualified person.

Thanks for the info guys. That AC is pretty interesting, thanks alot Mr Scout. I really think that welding is the way to go here from the research I've done and talking with a few Luscombe "experts." We'll see what the IA says.

I had a 1946 Luscombe 8A. There was a AD that said to replace the cast fittings with steel ones on the tail. Are we talking about the same thing?

Skystrider wrote:There was a AD that said to replace the cast fittings with steel ones on the tail. Are we talking about the same thing?

No, this is a different one.