Repair Your Aircraft Skin Panel With Cold Spray

Hello and welcome to the webinar on how to repair your aircraft skin panel using cold spray! We’re glad you joined us! Today we have Jarrod Shell from Mid-America Aerotech and he’s going to talk to us today about skin panels in the aerospace industry and how to repair them using Cold Spray. Jarrod, thank you.

All right, thanks Rob! Today we’re going to talk for the next 15 minutes very brief 15 minutes and talk about Cold Spray repair using on skin panels for aircraft components. We’ll be briefing this Cold Spray Technology itself and how we can effectively and safely repair many aviation components using this method. We’ll take a look at one specific repair on b1 that we wrote and managed for the Air Force and how that repair method can be brought over into the commercial aerospace world. You’ll learn a little bit about my company Mid-america Aerotech and how we can increase your ROI, improve turn times and help out with all of your maintenance needs out in the aerospace maintenance world. So, let’s see, like Rob said my name is Jarrod Shell, i’m a husband father, mechanical engineer, aspiring musician better in my younger days but a recent recently certificated pilot and I do some business development efforts here down in our shop at Mid-America Aerotech. 

For the last about 10 years, 11 years, I’ve been involved in cold spray aerospace commercialization. Back in 2007, a couple years before that, myself and a few of my colleagues were hired on to do research and development for the Department of Defense looking at new advanced manufacturing methods one of which was Cold Spray, and in 2011 our crew was picked up by a larger organization to commercialize Cold Spray for the aerospace sector. We did everything from cleaning the shops and sweeping the floors to going on international business development trips and everything in between— data generation being a lab rat in the process we got our FAA Repairman Certificate, so actually pulled the trigger on a number of the repairs that we were writing and working through the approvals with. 

In 2018, I started doing business development less out of the strict engineering role and out into the customer relationship kind of world, but I continue to work on applications development for our organization here in the West Fargo facility. 

So enough about me, let’s get into the actual aircraft skin panels, aircraft skin panels is a broad topic, a very broad topic, but every aircraft has some type of a skin panel on it. [The] main functions they’re they’re a wonderfully engineered, a wonderfully designed type of a product or a component and they serve multiple features. Primarily they’re providing that shape and that contour that aerodynamic contour to any number of airframes but they also serve to to aid in the pressurization functions on aircraft as well as absorbing some of those static and dynamic the flight and ground loads that that would be encountered during an aircraft’s service life. But regardless of function, these aircraft skin panels are facing the environment. Whatever they’re doing they’re facing the onslaught of rain and weather phenomena, they are constantly being exposed to things like foreign object damage or even just the normal de-icing fluid. You know the collection of these types of activities often results in wear and corrosion setting up on any number of aerospace components obviously, we’re talking about skin panels today but they’re out in service they’re working, and as a function of that service life are exposed to this wear and corrosion. 

Now about skin panels—many of them are firmly you know riveted in place, they’re not really move removable per se, they only get inspected once the airplane comes in for the helicopter comes in for phase checks. But, on some panels, these are replaceable and removable, but regardless of the wear or the corrosion that might set up on these things there exists an opportunity for loss. Now in the commercial world, we’re talking about revenue generation taking that airframe offline and making it unavailable due to the maintenance cycles for revenue generation. On the military side, we’re talking about warfighter readiness having that weapon system unavailable for any number of reasons affects our ability to go and and do functions out in the Department of Defense world. So, regardless these maintenance cycles have a tremendous cost to them. So, we’re going to dive right into one specific example and this was a skin panel repair that we had built and managed a little bit for the US Air Force on a  Rockwell B1 Lancer, the bone, and it’s FEB panel forward equipment bait panels. So the B1, on the nose of B1, you’ve got equipment bays right, and you’ve got panels right here that cover up those equipment bays, so creatively those are named forward equipment bay panels. Now these panels are meant to be removable– they are held on by fasteners, fasteners right these panels are aluminum alloy, lightweight– very strong design– but the fasteners that hold them on are a harder material and because of the repeated installation and removal of the panels and the fasteners that keep the panels on. These harder fasteners wear against the softer aluminum so over time over time this accumulated wear can lead to the growth of these fastener holes up into and past a point where they are they exceed their critical values, they exceed their service limits, and a repair needs to be addressed. Now, this is very, very common in [the] industry, especially in aviation maintenance [where] you have service limits that are set and a component exceeds that service limit. Once that service limit is reached, that component either needs to be repaired or replaced. Now in the terms of these skin panels on B1,  it was a very, very expensive component. The other thing about these panels, these FEB panels, is that they are match drilled, which means that they only fit on one specific airframe. You can’t pull one off of serial number one and put it on serial number two the holes don’t line up and so there’s a very long timeline to get replacement components like this made.

So, if only there were some method, if only there were some method that we could call on to do some sort of repair over and above this and improve against the standard repair methods. And let’s see how tech savvy we can get—yeah there it is—Cold Spray, enter Cold Spray! Okay, everybody’s having fun, right? So, Cold Spray. What is Cold Spray? Many people on this webinar probably have a topical understanding of Cold Spray, if not, a deep dive understanding of Cold Spray, but there’s also people [just] scratching the surface. So, we’re going to start right at the top and just do a brief couple minutes of what is Cold Spray? Simply put, we take powdered metal and blow it through a very specially designed “tube,” “nozzle,” “straw,” whatever you want to say. When we do this, and we accelerate these powder particles through the nozzle they get going mach 2, mach 3, and when they hit a substrate, they plastically deform. And that plastic deformation allows that powder particle to stick onto a substrate, and all these particles build-up, and build up, and you end up with a really nice deposit. It’s a solid state process meaning we’re not melting the feedstock at any point, they’re very, very, high strength, high density coatings or deposits. I don’t even call them a coating, it’s a deposit. Many of the options that we have available approach the material properties approach that of rod material. Adhesion strengths, our low base line is about 10 000 psi, and that’s just because that’s the strongest glue that we can find to do our qualification tests. I think there’s there’s plenty of literature out in the industry too that shows the actual adhesion strengths of many of these deposits can be 20,25 even more, thousand psi so very, very useful, strong, durable coatings. So what does all this look like in actuality? Here’s a very simple graphic of every step of the process. We take a worn element in the case of these FEB panels, the actual holes are oversized, maybe they’re oblong, maybe they’ve just grown, they’re the right size and position but they’ve grown past a certain dimension. Well, we’ll clean it up, expose some fresh substrate, and do a preparation step and that can t vary depending on the the spray that we’re using, and the feeds, and the substrate that we’re spraying onto. But, we’ll point the gun at the area of deposit or the area that we want the deposit to be on, we’ll make that deposit and then after the deposit is up to a sufficient thickness, we can immediately take it out of the booth, and go blend it–just mechanically abrade some of that material away and make it flush with the surrounding surfaces, and then go back and replace that feature that hole position, complete with the original chamfer dimensions and what not. So, we like to make it look easy–that’s our job to make it look easy, it can be very difficult and very technically oriented and there’s a lot of craftsmanship that does go into it but the steps are the same. 

I just showed a little bit about the skin panels here’s a few steps the same steps rather, on a gearbox or two different gearboxes.  Sometimes all it takes is a spray and a blend, and other times it takes a full reverse engineering element on critical elements of a particular component. Geometry that needs to be restored in a very specific manner. 

So, imagine now if you had access– here’s the pitchy part right– imagine now you had access to repair and restore these components that are lost to wear and corrosion you could stretch your maintenance budgets and at the same time have access to industry expertise– that’s us! Mid-America Aerotech– we are aerospace Cold Spray experts, we operate a repair station, a part 145 repair station, in West Fargo North Dakota, where we have our EOS of certificates, our certificate dual as 9100 d and 91 10c certificates, and I say our technicians and engineers are among the best in the world, and we have stiff competition out there. I know that my guys can handle anything that [the] industry can throw at them, we do live in this world of aviation maintenance, we have dabbled and continued to support our academic and commercial research clients as well as pretty much every step along the way everything from prototyping, and repair, development, through first article and low rate production, and all the way scaling up to full-scale production. What are we asking for? So you’re at this webinar, we’ve learned a little bit about skin panels and how Cold Spray can be used to repair these skin panels, so what are we looking for? We’re looking for customers, partners, and industry partners, who either have corroded and worn assets that “hey, maybe Cold Spray looks like something that we can use to repair and restore this hardware.” Single units—so hard to find, hard to acquire hardware, think about like warbird restoration, a high value in keeping that exact serial number all the way through the manufacturing and repair process. Or, diminishing materials, or manufacturing sources items things that have been out of industry for a long time and we’ve lost some of the manufacturing capabilities on a certain set of hardware. So, if you have these, if you’re maintaining a fleet and you have problems with your supply chain– talk to us about figuring out how to repair these components instead of replacing them! If you are maybe a warehousing organization, right, and you have stock lines of parts, and you have the ability to accumulate a batch size of five or ten components you can send them our way. We can work on some cost sharing to figure out what the right balance is, and get these components repaired and available for your customers to have immediate access to expedite the turn times and to really be able to add value to your customers’ operation or your operation directly. 

When you partner with Mid-America Aerotech, you have access to the very best expertise in the industry. Now, what we typically charge out in industry is a test and evaluation fee, a couple hundred dollars, and totally worth it even at five hundred dollars we bury way more cost into our testing evaluation than we ever receive in our T and E fees. And through our typical evaluation we’ll run a component or an opportunity through our viability filter, and we’ll keep a small report to kind of be the seed as this product moves along through the line. Now where we’re kind of we’re doing the salesman thing because this is a fantastic deal we’re dropping our testing evaluation fees down to 150 bucks, a massive deal at 500 bucks even better at 150. All you have to do is send us an email at and in the subject line write: web underscore ev, and send it to my attention: Jarrod. In addition to dropping this price to an astronomically you know affordable 150 bucks, we’re including that test and evaluation report: that write-up that we typically keep as an internal document, we’ll go ahead and forward that back to you for your reference so at the end of the day at least you’ve got a real good look at what Cold Spray can do for your hardware. So, I want to be stewards of everybody’s time, time is very precious and so I appreciate the the moment that you spent with us this afternoon. We do have a little bit of time here for Q &A, and maybe if there’s anybody that has any questions go ahead and type them into the chat function and we can we can go ahead and read those off. In the interim, I just want to say thank you, like I said time is precious and we appreciate even the small amount that you spend with us. If you have any questions or just want to know more about Cold Spray, you can use that same email address:, and we’ve got several brochures that we’d be happy to send out, or just call and have a conversation with us to see if Cold Spray could be used in your organization! 

We do have one question, actually we have a couple questions, the first one is: How do I evaluate whether my skin panel can be repaired? How do you evaluate? 

Give us a call! Give us a call! I mean, there are certain features, certain types of problems that are very straightforward to repair, and some are very–Ii would say more complicated.  So,  with that first phone call with that first evaluation, what we can do is figure out where in the spectrum does does your particular part fit or fall and then we can kind of take the next steps after we take a good look at it and give you our best approach. 

Great, great. We got one more [that] we have time for: is there FAA documentation required when completing skin panel repairs?

Depends on on who the customer is for. For FAA governed components, absolutely, we would work with your—maybe you’ve got engineering representatives on staff—maybe you have access to contract DERS, or maybe you just have a panel that needs to be fixed, we have access to a whole slew of DERS as well, that we can, we can develop, that repair specification and work with the appropriate approval function whoever the DER is, that whether it’s ours, yours, or somebody else’s. We would work together with that DER to ensure that all of the appropriate regulatory elements are properly addressed.

Great! And we got one last one: Scott is wondering about can you use the aluminum cold spray as a structural repair on tempered parts?

So that’s i think–that’s probably a loaded question, because it actually is two different questions. Can you do it? Is it possible? I would say the answer is absolutely, it is possible to  build up very elegant deposits that can carry load through whatever your design criteria might need. The second part of the question is in terms of aerospace maintenance can you get it approved, and so we would have that continual discussion with the DERS to find out: “okay, what does this part [or] area need to do? How does it need to function from an engineering perspective and how can we engineer that deposit to serve that function, and run through the appropriate ways to check and make sure that what you said happened, and and is actually performing that way after it’s been applied.

Excellent! Well, Jarrod thanks for your time, and thank you for the presentation and thank you to everyone that turned out for the webinar, [it is] greatly appreciated, and [we] hope we’ll be having more webinars and so hope you can sign up for the for others in the future. Any last statements, Jarrod? Just thank you, thank you for your time and I hope to hear from everybody soon! Great, thank you. All right, thanks Rob. 

Skin panels are essential aircraft components. They keep the plane pressurized, they provide shape and contour to an airframe. Some cases, they are designed to help carry flight and ground loads. Some are affixed permanently (until the airframe comes in for inspection) and some are designed to be removed after every flight. Regardless of the function, these panels are in constant exposure to the environment. Over time, corrosion or wear can inflict damage to these essential components. Regardless of the reason, damaged panels need to be repaired or replaced. Because these panels come in a variety of shapes and sizes they can carry a wide range of costs. On some airframes, these panels can cost into the hundreds of thousands of dollars. In addition to the expense, many of the larger and more complicated panels can be difficult to source. They can carry lead times that inhibit the availability of the airframe. This can lead to loss in revenue generation or an organizational reduction in capability. It is imperative *and* tactically advantageous to get these panels repaired and re-installed in a timely fashion.