it wasn't just on Mustangs that the issue happened i had the issue on my 2008 escape,2001 ranger pretty much anything with an aluminum hood/panel you are going to have issues...i have seen it on Dodge's,chevy's,fords,etc....i was told by ford the issue is known and unless it perforates the panel they are not interested in hearing from you and it comes out of your pocket for repair even though they know it's an issue....a group started a class action lawsuit and lost so you might as well bite the bullet and repair it yourself...my dealer gave me a paint pen and said good luck

 

IIRC! Mopar and GM don't use aluminum panels/hoods, but rather galvanized steel only

 

Fiat/Chrysler is being sued over Aluminum panels in the Jeeps and they knocked 225 pounds off the Ram using aluminum and GM has it in their hoods and tailgates on the trucks and SUV's.

 

It still amazes me that they can't get this right. Aluminum can be painted and not corrode, they've been doing it on airplanes for a very long time. My understanding is that the issue is caused by iron contamination in the welds, which causes galvanic corrosion. I don't understand why they can't keep the iron out of the welds.

 

Thanks for clarifying, I stand corrected

Your understanding is spot on, as the issue is indeed caused by iron contamination in the welds, which causes the galvanic corrosion

 

And yet when you call then out on it they just respond "Non Our Issue, there is no recourse and repairs will come out of your pocket". I even had a Ford Body Shop call it in and then were told unless the corrosion perforates the panel the repairs are to be paid by the customer, didn't make a good impression on me as i only had the car 3 days before i noticed it really bad around the curves around the headlights i was told i had 2 options if i wanted to fix it and it was replace it or wrap it... i am looking for the same hood i have as i want to get it airbrushed smoke coming out the heat extractors and a demon face between them so i will be looking for a while longer but the stalker hood would look good as well on the car

 

Well, that's a mighty broad statement and also you need to go have a look at airplanes again.

Airplanes are painted with primer, paint, and sometimes clear coat. So just like a car, right?

Except not. A car goes through that e-coat primer bath, then gets inappropriately dried out, then gets shot with paint and clear or paint, paint, clear if it's a tri stage. It's all automated. And the cars are not meticulously washed and inspected before they go through the paint line.

Now, new, an airplane is quite a bit higher dollar thing, depending. Oh, sure, there are million dollar cars, but that equates to a Citation X or something like that. Class for class, a Cessna 172 is the airplane equivalent of a Toyota Camry or something, eh? And a new one of those in 2018 was over $350,000 new, and that's the stripper model.

Given that pricing, they spend a little more on a paint job for a few reasons. One, aerodynamics. Better prep, better smoothness, better airflow. Secondly, they want that paint to *freaking stick*, so they wash and wash that plane until it's absolutely spotless in a very controlled environment. Water on the ground to catch and keep any dust during operations. Airflow controlled and filtered as much as possible. All the tricks are used, as the person paying a giant sum of money for that new plane is absolutely NOT going to be happy if the paint falls off.

They paint the absolute minimum amount of paint on the aircraft as well, as each *ounce* unneeded means fuel waste. American's old bare metal scheme saved them quite a bit of money, but today's planes aren't made of metal as much, with lots of composites (or mostly composite in the case of the 787 Dreamliner from Boeing) taking over and making a mess of the old scheme. You won't see unpainted planes much anymore, not even the old days of cheating with the bottoms remaining unpainted as used to be the case.

They lay the primer on, wait. Lay the colors on, which can be quite the process if it's a special livery, then when it's all done, wait. Then might also put a slick clear coat for final and wait, then deliver the plane.

All by hand. No automation. Aircraft painters are masters of their art.

Now, truth, the paint does stick better on the airplane, and that's because they did it *right*. But it's expensive to do that, as you can imagine. Hand painted? All that prep? Nosirs/madams, Ford et al don't have time/money for that, and neither do you. If you want to spend another 20K or more on that paint job, then you are more than welcome to take the car and have it done properly like an airplane. Or, oh, I dunno maybe 1000(?) to do just a Mustang hood and hope it matches well... good luck with that all aluminum F150 though. But that's not a mass manufacturing efficient way of things, and so the car is not done that way. It's done with the warranty in mind, and that's it. Including, yes, the corrosion of aluminum. Ford figures, correctly, even after all these years, nobody cares enough to make THAT kind of stink about it, and anyway you should be buying another one already.

And if the airplanes were done as cheaply as the cars were for paint, their paint would do exactly the same thing. They are not, and that's why the paint sticks (although eventually it doesn't, plenty of airplanes out there show this.) Prep work. It's all about that first, the paint won't work unless you do the stupid amount of prep before you lay down even the primer.

One other thing. For airliners they'll repaint them every 6-10 years for either livery changes, special one offs, or just to ensure the paint doesn't make the brand look bad. Dingy airliner? Nobody wants to fly on that.

So. There y'all go. More than you wanted to know about airplane painting, but I felt it rather important to note given things.

Enjoy this video of an ex-United 757 being repainted for its new role as a FedEx freighter!

 

Thanks for the in-site Houtex it all makes sense!

 

the other main thing is that planes don't have welds with iron contamination . . . pretty sure not many welds at all; more rivets and adhesive bonding . . . and they know how to deal with galvanic corrosion, because they deal with dissimilar materials (aluminum/carbon fiber composite, aluminum/steel) all the time . . . . maybe they should adhesive bond the seams on the hoods and stop welding completely?

 

This It makes even more sense IMHO

 

Well, no, they use dissimilar metals everywhere on the aircraft. And they experience corrosion just like the Mustang hoods. Direct from Boeing:
https://www.boeing.com/commercial/ae...7/corrosn.html

The thing is they use metals they've determined can at least tolerate each other somewhat, materials to coat or space or such the materials so they don't touch, perhaps install sacrificial anodes (see boating) for that if possible... all the tricks that a car manufacturer can't/won't do for cost reasons. This is why a a 23 year old 737-700 Southwest Airlines airplane named Herbert D. Kelleher can continue to fly 5 hops a day: They made those things right, but they spent the time and money to make it right, and continued to learn all the way and apply improvements.

If the car manufacturers used the same material awareness, procedures and such as the aerospace people did, the Mustang would cost 5 times as much and probably be lesser in content as all the money went into ensuring the hood didn't bubble. You can't mass produce a car and expect aircraft quality. The money's not there Not for the research, not for the materials, none of it. Cheap, remember, get it out the door, sell it, wait 5 years, repeat customer. Ergo, bubbling hoods. Yes they *could* do all that stuff and never have the bubbles. They simply won't. Stop buying their crap and maybe they fix it, like the cars of 1970s-80s when the Japanese made huge strides in American markets because American manufacturers were producing utter garbage. They've learned nothing...

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Regarding welding, oh yes, absolutely they do. TIG or friction stir, they weld aluminum all the time in aircraft. Some things need welds, some things need rivets, and there's pros and cons and most importantly (to the company) costs involved that make the decision.

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Um... I don't think they're welding anything on the hood... panel bond here and there, sure, but not welding. They put panel bond on the structure panel stamping where needed (middle bits for prevention of flappage, outer bits for locational reasons), then place the outer skin stamping on the structure panel. Get it centered (manufacturer has a jig for this, body shop will have to do their utmost to get it right), then they pinch the outer edge of the skin around the edges of the structure panel. Panel bond cures and the hood is complete, ready for paint. Steel or aluminum, this is the way. They may apply some tape or such on the edge pinch for reasons(tm), but they ain't welding those things. They might do that for a door or something. Oh, and some of the skins used are pre-bent around the edges so it's almost a drop on over the structure and pinch situation. Not always, surely. and/or maybe you just need a bit of skin and not the whole thing, that's your call, body workin' person.

The that that's interesting to me are the fasteners in the hood... those are interesting. The S550 has studs, and I'm guessing they're steel. They must be jigged up in the structure panel and panel bonded in there. Once they get fastened they'll just tighten down and stay. The S197 and back are bolts into u-nuts, I believe. Very interesting indeed they went studly. And one wonders how much those pieces have to do with the entire bubbling process... but I'm probably overthinkin' that one.

 

yep, the key with using dissimilar metals; or any materials with different galvanic potential together in the same structure, (such as metallic fasteners in a carbon-composite structure) is to insulate between the materials so the galvanic action can't happen . . . . impossible in a weld for practical purposes, very do-able with assembled or bonded components

those sure look liked like welds to me on the bottom of my hood where the corrosion started, but maybe I'll have to take another look

if the bolts/fasteners in the hood and/or the threaded holes are painted before assembly, that's probably enough to stop it or slow it down

 

If painting the fasteners/bolts and threaded holes before assembly would be enough to stop/slow down the corrosion process, then why didn't Ford take that into consideration in the first place?

I really don't think it would've increased manufacturing costs by very much, if any at all IMHO

 

Actually this is why I always go back and get my fasteners from Ford, the ones that go across 2 metals are all coated. This also why you are supposed to get new fasteners, most do not to save on cost.

 

So rather than saving costs by not getting new fasteners that are coated, it's costing more in the end after paint bubbles up on the hoods from galvanic corrosion