As I recall, the USN first experienced filiform corrosion in the early 1960's on the P-3A Orion patrol planes, in conjunction with the introduction of polyurethane paints. These paints were much less porous to moisture that was trapped underneath than older paint types. The solution was careful surface preparation, and Alodine conversion coating prior to painting. Even when spot repairing corrosion, when the bare aluminum is exposed it is given spot Alodining before re-painting. Everything in the navy is about corrosion control! Cheers, Bill, retired NFO.
Without revealing my educational background, I will disclose that I had a course in painting. Rules 1, 2, 3: Surface Prep Rule 4: match the primer to the surface and the paint to the primer. Ironically, the only color mentioned in the whole course was "red lead."
I just replaced both ailerons in my 1961 V-Tail due to filiform corrosion. In three months it went from a couple of quarter sized rough worm tracks to covering a great deal of the control surface. My airplane has always been hangared and lives in Michigan. Total cost to have them re-skinned in aluminum, painted and balanced was $7,500. Great content as usual. Thanks FlyWire.
I had both elevators on our F33A refinished about three years ago due to corrosion. It was quite a lengthy process to get all moisture removed and then refinished. Had them done in Ennis and they're doing well. I learned from your video the technique for checking them. Great information. Thank you!
We just had our magnesium ruddervators repainted on our ‘79 V- tail. We had been tracking it for a couple of years but like Scott noted. Suddenly we noticed that it had rapidly grown & expanded. Fortunately, the paint shop says it was very minor & the repaint went well. They really look very nice now.
Good video. Plenty of filiform on outside stored Cessna aluminum elevators here in the northeast. Pipers as well. As you point to..trailing edge of control surfaces is common in my neighborhood. Keep the videos going . ABS is making progress for us V tail folks. I corrosion X my control surfaces internally as well . Good subject and advise .
Water is incredibly corrosive. What etching does is remove the oxidized layer, and the alodine basically seals it by leaving a very thin coating on the metal. The etching clears off the 'dead skin' and leaves a surface that promotes adhesion when you prime and paint. For plain aluminum the surface eventually is exposed to the elements and corrosion will follow, aluminum, steel or magnesium. Thanks for watching!
Hi Flywire have tryed treating the magnesium with a process called magnesium dicromate. from working on the p&w r2000 engine the engine casing are made from magnesium and we treated the casing with this process before painting, it works the same way alodine does on aluminium.
None- Well, there is a solution for the straight tails, STC'd aluminum replacements for the ailerons and the elevators. The V-Tail Ruddervators have much closer tolerances for balance which compounds the problem. There are a couple of folks working on a solution, but none is approved a of now.
Hi Scott, have you ever looked at stray electrical current as the most significant contributor to galvanic corrosion.? Stray current contibutes to more than 98% of corrosion. There is a great product used in the marine industry, SeaBis. Cheap and Easy to use and it works. Check it out!
Sure Jon. The MX manual specifies what procedure to use and it varies between models slightly. But basically you hang it by the fulcrum and adjust the balance weights in the nose of the control to within spec. Are you asking for a video on how that is done?
On the older Bonanza's there are magnesium horns on the tail feathers and some on the nose gear fuselage mountings. The fuselage nose gear mountings are in the lower cowling where water collects.
Being a pilot has nothing to do with it. The folks that make magnesium parts just don't sell the stock to make these elevators/ruddervators these days.
Good question. A=From what I understand it is not as big an issue. The controls were originally dipped for the conversion coat. They weren't stripped and repainted like the outsides, Possible, but less likely.
Student A&P here. We just recently learned about corrosion in class, and this helps explain it a lot better. Thank you!
As I recall, the USN first experienced filiform corrosion in the early 1960's on the P-3A Orion patrol planes, in conjunction with the introduction of polyurethane paints. These paints were much less porous to moisture that was trapped underneath than older paint types. The solution was careful surface preparation, and Alodine conversion coating prior to painting. Even when spot repairing corrosion, when the bare aluminum is exposed it is given spot Alodining before re-painting. Everything in the navy is about corrosion control! Cheers, Bill, retired NFO.
Good info Pelican!
Without revealing my educational background, I will disclose that I had a course in painting.
Rules 1, 2, 3: Surface Prep
Rule 4: match the primer to the surface and the paint to the primer.
Ironically, the only color mentioned in the whole course was "red lead."
I just replaced both ailerons in my 1961 V-Tail due to filiform corrosion. In three months it went from a couple of quarter sized rough worm tracks to covering a great deal of the control surface. My airplane has always been hangared and lives in Michigan. Total cost to have them re-skinned in aluminum, painted and balanced was $7,500. Great content as usual. Thanks FlyWire.
Jim- Thanks for watching and commenting!
Hi, is there an aluminum re-skin option for these V tails? I'm facing the same issue.
@@flydogairventures4318 Yes, I had my ailerons reskined in aluminum.
I had both elevators on our F33A refinished about three years ago due to corrosion. It was quite a lengthy process to get all moisture removed and then refinished. Had them done in Ennis and they're doing well. I learned from your video the technique for checking them. Great information. Thank you!
It’s a “GOOD-DAY” when you learn something new . . .
As I “thought” only the V-Tails had the magnesium ruddervators/elevators!
Great video! Very informative. I've been "monitoring" some filiform on my V35. Time to take care of it.
Thanks, if I helped save your Ruddervators then the video was a success!
We just had our magnesium ruddervators repainted on our ‘79 V- tail. We had been tracking it for a couple of years but like Scott noted. Suddenly we noticed that it had rapidly grown & expanded. Fortunately, the paint shop says it was very minor & the repaint went well. They really look very nice now.
Good catch!
I just sent my right trim elevator on V35B for worming ... got it home just before the pandemic hit, lucky. Love this topic
Where are the good paint shops in the Midwest?
Good video. Plenty of filiform on outside stored Cessna aluminum elevators here in the northeast. Pipers as well. As you point to..trailing edge of control surfaces is common in my neighborhood.
Keep the videos going .
ABS is making progress for us V tail folks. I corrosion X my control surfaces internally as well .
Good subject and advise .
Water is incredibly corrosive. What etching does is remove the oxidized layer, and the alodine basically seals it by leaving a very thin coating on the metal. The etching clears off the 'dead skin' and leaves a surface that promotes adhesion when you prime and paint.
For plain aluminum the surface eventually is exposed to the elements and corrosion will follow, aluminum, steel or magnesium.
Thanks for watching!
Hi Flywire have tryed treating the magnesium with a process called magnesium dicromate. from working on the p&w r2000 engine the engine casing are made from magnesium and we treated the casing with this process before painting, it works the same way alodine does on aluminium.
Yep, alodine is a good process for Aluminum, but not Magnesium.
The best primer after the magnesium conversion coating treatment is a two part epoxy primer.
Such beautiful aircraft. Why do you think no other solutions have yet come to market? Tort? FAA? Actually no one has a likely solution?
None- Well, there is a solution for the straight tails, STC'd aluminum replacements for the ailerons and the elevators. The V-Tail Ruddervators have much closer tolerances for balance which compounds the problem. There are a couple of folks working on a solution, but none is approved a of now.
Hi Scott, have you ever looked at stray electrical current as the most significant contributor to galvanic corrosion.? Stray current contibutes to more than 98% of corrosion. There is a great product used in the marine industry, SeaBis. Cheap and Easy to use and it works. Check it out!
Richard, filiform corrosion is electrically based. In the airplane world, especially in the certified world, you have to use approved products.
Could you explain in the future how the control surface(s) is balanced after painting.
Sure Jon. The MX manual specifies what procedure to use and it varies between models slightly. But basically you hang it by the fulcrum and adjust the balance weights in the nose of the control to within spec. Are you asking for a video on how that is done?
@@FlyWirescottperdue Yes, I think that would be very informative.
Isn't the balance mass in the triangular "horn" of the elevator? (Behind you, in most of the video)
For the F33C, the horn is the weight.
Was wondering if you were going to change your platform from RUclips to a alternative site in the future?
No plans to right now. We’ll see how things go.
@@FlyWirescottperdue Thanks for getting back to me. :)
I have 2007 Bonanza - does it have magnesium control surfaces?
As far as I know it does. I haven't seen your logs.
On the older Bonanza's there are magnesium horns on the tail feathers and some on the nose gear fuselage mountings. The fuselage nose gear mountings are in the lower cowling where water collects.
Not a pilot, but just curious why no one makes those replacement skins. I guy would think there would be a huge demand.
Being a pilot has nothing to do with it. The folks that make magnesium parts just don't sell the stock to make these elevators/ruddervators these days.
And how likely are you to have or find this type of corrosion inside the flight controls?
Good question. A=From what I understand it is not as big an issue. The controls were originally dipped for the conversion coat. They weren't stripped and repainted like the outsides, Possible, but less likely.