Airworthiness shop or Repairman for Wing Tank Repair

[8296]

I am in the Dayton, OH area and have owned my 1946 C120 for over 40 years. I am plan to pull the wings and recover with Stits Polyfiber for the second time during my ownership. The problem is wing tank corrosion which I found to be not an uncommon problem as noted elsewhere in these tech forums. The left tank filler neck has visible rust and needs to be replaced and the right shows signs of corrosion starting there too. I had tracked down a source for completing this type of repair but that mechanic recently had a stroke and has since retired. That shop has no other mechanic qualified to do this repair. Does anyone know of a shop certified to do this type of repair and/or a FAA certified mechanic qualified to do this repair? The Midwest would be a preferred region for shipping purposes but as they say sometimes beggars can't be choosers, especially with aircraft.

George
N72123

[6468]

Hi George, I'm in Dayton OH also, Try Rob's Welding off Needmore Drive. He welded up my C-85 oil tank. He does a lot of exotic welding for Wright Pat AF base labs. He should help advise if welding or brazing is best. I lot depends on the extent of the cracks/corrosion and their locations. Might also want to investigate getting a tank from a salvage yard, may be better in the long run. When re-installing use soft rubber strapping & get rid of that felt! I'm at Green County and helping a guy with another 140 at Moraine. There are guy's in the area that can help. I'm in the club directory, feel free to call if you have questions. Jim S N2588N

[6643]

If you want another option, give Safe Skys Aviation in Middletown a call. I don't know if they will be interested, but they do a bang up job overhauling Ercoupe tanks. Ask for Kurt and tell him I sent you.

[8296]

Jim, thanks for the information. I live not far away from Needmore and will contact him and see if he can do the repair. Looks promising. I guess a follow-on question is if he can, do you have any idea what is a good source for a replacement filler neck and cap - Univair? I have not sourced that out yet. Oh, I did look at local the IA / A&P listing after returning to the Association yesterday and saw that there were two individuals in Dayton area. I guess I am lucky, having two mechanics nearby that understand this aircraft. I've done a lot of work on my aircraft over the years and understand the airframe structure and systems very well but have always done the work with IA / A&P oversight.

. . . and John C, thanks for the lead to Safe Skys Aviation as another source.

George
N72123

[V529]

Have you considered just getting a used serviceable tank? "Williams Airmotive" (Now I think the name is Airframe components) has an amazing selection of wings and flight controls for Cessna and Piper. I got a couple of good tanks from them years ago. Any salvage yard would probably have some as well.(if you can't get yours repaired)

[a64pilot]

Usually the way this works is the repair is done by a professional welder, the A&P inspects and signs it off and reinstalls the tank, as not many A&P’s can weld sheet metal aluminum well.
Do get rid of the felt, I used pretty stiff rubber, neoprene sheets bonded together with fuel tank sealant to get the right thickness.
But whatever you use, use closed cell so it can’t soak up water.
I haven’t seen my tanks for at least 15 years or so, but surprisingly they looked factory new with no repairs, I had them painted with the same jet-glo that the airplane is painted with, I think being painted with a good quality aircraft paint may help prevent corrosion.

Just do not slosh your tanks

[8296]

I think being painted with a good quality aircraft paint may help prevent corrosion.

I just want to make it clear that I am discussing corrosion inside of the fuel neck. I would assume that after 70+ years any "built in" resistance to corrosion in the metallurgical structure at the surface of the metal has gone Tango Uniform. I also wonder if the neck metal is different from the tank shell metal (not iron based?) and it may be that the iron based neck metal is lower in the galvanic series (sorry for the tech talk here) and acts as the sacrificial material, i.e., the anode. I would assume that the neck portion has a lot of exposure to moisture over its lifetime as any moist air existing above the pool of fuel can form small surface water droplets as the tank cools, especially overnight. Am I overthinking this stuff? Maybe.

Salvaged tanks are my only option if I can not find a repair person or facility; however, because of what I discussed above care has to be taken to make sure the replacement tanks are not on the verge of repeating the condition I already have discussed above. If I recall correctly the A models are now over 70 years old. Thus,the "youngest" tanks available on the salvage market are already over 70 years old and they (Cessna) are'nt making any new 120/140 fuel tanks, that's for sure!

[6643]

I went through this years ago, but I don't recall if it was Cessna tanks or something else. Anyhow, the way the tank was constructed, a steel neck was fitted into an aluminum tank and the parts were "fused" together by melting aluminum into the joint, sort of like a cross between welding and soldering.

[6643]

I guess it was Cessna. Here are some pics from the old forum.

[6643]

the steel flange is threaded and the welding or brazing rod fills in the threads.