Aircraft Painting: FAILURE (and SUCCESS) 

You caught me at "the standard is perfection" So I thought you could use and understand what I've written. 1. Alumiprep 33 and then Alodine or instead of Alumiprep and Alodsine, just use Prekote 2. Prime with primer designed and engineered for use on aluminum 3. Paint with a topcoat designed for use with the primer you're using. * That "Aircraft" paint stripper specifically says on the table "not for use on aircraft". That's because it corrodes aluminum (it causes hydrogen embrittlement) you need to use a non-chlorinated paint remover like Eldorado PR-2002. I also don't know the primer you're using that was peeling off, but that looks like a big problem. It's not an etching primer and looks like something you're get off the shelf at Wall-Mart. When you showed where the paint was coming off I saw big scratches in what I'll assume was Alclad; and I didn't see any kind of conversion coating like Alumiprep 33 and Alodine or Prekote either. So I'll venture to guess you used Scotchbrite to roughen up the aluminum surface so the paint will stick (which obviously didn't and it doesn't work. Have you ever heard of an auto-body shop sanding down bare metal IOT get paint to stick). So here's another problem that Alclad has (had) a pure aluminum coating on both sides 5.5% of the sheet thickness. When you used Scotchbrite to roughen the surface, you removed the pure aluminum coating and opened the core of that 2024-T3 (copper and magnesium) to corrosion. On a sheet of .025 Alclad, the pure aluminum coating is .001 of an inch thick - so you've ruined the corrosion control of the aluminum right there. The next part about the conversion coating does two things, it seals the metal with an oxide and it provides for a molecular bond between the primer and the metal. I don't know what kind of paint you are using, but you're apparently spraying it too thick / not viscous enough. You seem to have the other components about tip size and air pressure at the wall and gun - so what's left is the paint. www.axalta.com/content/dam/NA/HQ/Public/Nason/Documents/TDS/NSN-TDS-Ful-Cryll-II-ID-Quality-Eng.pdf Here's a link to a TDS for paint I'm familiar with in spraying corporate jets. The TDS gives you a good starting point on how to set up the paint and your gun. Then practice on a piece of scrap Good Luck- I'm providing this not because I'm insensitive or mean, I just want to pass on information I found in my life to someone who could use it. This information took me a long time to compile. None of which is mine, i'ts compiled from hours and hours of research.

You are the first builder to Express my same problem with primer not sticking to the ailerons. I tried three different primers and many prep variations... and finally gave up. I fly my plane with a horrible paint job!

Wow, such much I never knew about prepping and painting parts. I very much admire your attention to detail in every detail of this build. Also, you are so correct about taking your time and doing it right. I just know for a fact that this plane is going to look AMAZING when it's finished. Great job and thanks for sharing the videos with us!!!

I always enjoy your comments, honesty, tips, tricks and thoughts. Its of great help when building. Ive followed your channel with great interest.

I notice the air filter and regulator set in the back ground, I had the same set. The air filter is good (although I built in a pre-filter to protect the expensive filter cartridges), but the regulator is not that good. As your air compressor system goes through pressure cycles that regulator will follow it, just at reduce amplitude, example say 30 PSI compressor cycle, output from regulator would be about 3 to 4 PSI cycle. Plus it is pretty restrictive; meaning to get the correct pressure at the gun requires a much higher pressure setting at the regulator. If you are using a HVLP gun, they are very sensitive to pressure variation. They can go from great finish to orange peel with a change of pressure about 2 PSI. This is the regulator I put on my system which gives a much more stable air supply, has much less pressure drop at any given flow rate. So, on small parts you are not seeing much pressure change, but you are on larger parts. www.amazon.com/Parker-R119-04CG-Regulator-0-125-Pressure/dp/B007FXJVS2/ref=sr_1_fkmrnull_1?keywords=Parker+R119-04CG+Regulator%2C+0-125+psi+Pressure+Range%2C+Gauge%2C+150+scfm%2C+1%2F2%22+NPT&qid=1553016475&s=industrial&sr=1-1-fkmrnull Good Luck.

good stuff, thanks for sharing, looking forward to more on aircraft painting.

Wow! Looks nice!

I've hand-sanded all the paint off a steel bike frame I'm hoping to repaint with rattlecans. Decided to do the fork by itself first, before doing the entire frame. I ran into some problems when I sprayed the first coat of primer. Turns out I knew a lot less than I thought I did. I wiped it down with mineral spirits one final time, just before spraying the primer. The primer gradually became peppered with dozens of little pin-holes. I never added a second coat because of that and the project is currently at a stand-still. And worse, the primer wasn't curing all that quickly, so I set it aside to do some online research. I found out a couple things. One was that mineral spirits can look like it's evaporated & dried completely, but that in fact some residue can remain on the steel for a while. I didn't wait long enough before priming. So, after a couple weeks, the primer was still not fully cured, but still tacky & gummy. Totally clogs sandpaper in a single stroke. Plus, I found out that it's often best to add the topcoats only maybe a 1/2-hour after the primer goes on, or else to wait a few days when it fully cures. This primer will all have to be removed, and I'll wipe the metal with acetone the next time around. Did you find out why your primer wasn't adhering to the aluminum? I wanna learn everything I can about primer, now. And are there any other pointers you might pass along? This bike is a special one for my adult daughter. I'd already restored a very-similar bike for her boyfriend last year, while all she's had is a cheap old Huffy I fixed up for her. Thanks in advance for anything you can tell me. And thanks, too for making this great video.

Hope i live long enough to see the Cruzer completed.

Awesome job ; if you want to have less orange peel in your paint 1-st you need to paint as many surfaces as you can lying on the horizontal 2-nd use always slow activator/ reducer ( that will help flow the paint/clearcoat and eliminate the most of the orange peel) 3-rd increase the air pressure. And if you need absolutely perfection, after you did apply the clearcoat , sandind down with 1000grit and do a flow coat on top that will give you a perfect 100% shiny surface. Hope that help

it sounds like the initial layers and the time -between coats,,as well as the amount of paint on each coat,,,that is were the cris/ cross pattern, between coasts layers,,, as in the first and the second coat. the distance of your gun and the speed of your movment also plays a part. great vid buds

My buddy did his old Corvette as practice before doing his C-172.

I love you're channel .keep it coming

Hey - great videos! Wanted to share that if the first part of your paint job looks great, then is followed by orange peel - you are likely the victim of decreasing pressure getting to the gun. When your compressor starts, it's full up, but as you paint, the pressure drops and can make a huge difference. You probably already figured that out.

Your right with making sure the settings are correct and paint mixed properly. After that it's technique. Paint towards the unpainted surface. Here's the best tip... Don't look at what is being painted, look at the reflection of each pass. Watch to lay enough paint so that it can level. Just before it runs, it will gloss. That's where you want it to be. Practice on a large car hood from a junk yard. You'll see what I mean about how it will gloss.

The technical data sheet for the epoxy primer used calls for prepping the surface with 80 grit DA paper. The maroon nylon pad you used is only about 320 grit. I suspect that might be the issue with peeling.

Hello Bart, Thank you for informing the result of your (heavy and difficult but also great work you doing) on your fantastic plane. Believe it or not but I understand completely your drive to perfection and also I have so many respect for it. Nevertheless please keep with your feet at the ground. You forget that it's not a Ferrari but even then it's only important when leaving the showroom. I hope your plane finally flying in the sky. So it's not into a museum where people is watching with the nose. Also the sun take's his bit and other little grid will damage your work in time more and more. Please keep you standard als guidance but don't let it take over a leading position which only results in frustration which is not right and you certainly do not deserve! Thanks again and have a nice time with building your plane. Bye bye!!

One thing you might want to try before getting back to the plane is to get a bunch of automobile doors, hoods, trunks and practice your painting technique. Holding the gun, distance from tip to surface, speed at which you are moving the gun. Practice couldn't hurt.

Something to double check may be your filter/dryer combo. Is it sized properly to your system? It seems like it could be a bit small for your system and usually these should be separate to be more efficient (water separator / filter / desiccant dryer). It may be becoming overloaded due to the increased spray time of larger panels.

Did you prep the aluminum with something like Stewart’s EkoEtch? That would give the aluminum a “Tooth” for the Primer

Keeps us posted on the fix for the issue.

Most of the comments are about the orange peel. In my limited experience, that is mostly from the thinner speed and not quite a wet enough coat to flow out. My biggest concern would be why the primer did not stick. It would be disheartening to see the paint peeling one year after getting it all done. Have you figured out what caused the lack of primer adhesion?

I wonder if it makes a difference to getting orange peel, if the part you are spraying is standing upright, or laying flat ?

I'm glad your taking pride in your work! As Billy Crystal would say as (Fernando) on his skits on Saturday night live " It's better to look good than to feel good" I'm sure it will look great when your done and at 2000' no will ever see any flaws in the paint. Thanks for the videos.

What kind of paint are you using? I will be using the Stewart “waterborne” paint on my Rans S20 project. My advance research suggests that this particular paint is prone to orange peel if applied in low humidity. The advice I have heard to avoid this is to water down the floor of your paint booth before painting...presumably this slows the drying process. Not sure how this affects orange peel...maybe slowing the drying allows more time for the paint to self level? Good luck sorting it out. It’ll be a year or so before I’m ready for paint.

Before priming, don't sand too fine. 600 grit is probably fine enough (for priming). You don't want to see any reflections in the surface or the primer may not stick well enough. Leave the gloss to the top coat

Hello , i have a question How to become a airplane painter

I hope you are using a good etching primer Not regular primer, it has to be an etching primer designed for bare aluminium. Painting is a tricky thing. It's all by feel as well as knowing your product that you are using. Small adjustments in your mix can do magic. Got to get that flow just right. I have painted cars and never needed wet sanding and buffing. They came out looking like a sheet of glass. Again it's about knowing your product. Air temp, humidity, air pressure flow rate and your mix is crucial to doing a great job. Using fast reducer, med reducer or slow reducer are all key. Best thing to do is talk to guys that paint for a living. Just tac cloths between coats.

What paint are you using?

No clear right? Any reason why not to?

If it's flat surfaces it could be a convection issue. Maybe have a fan blow air over it as you paint it.

Painting is filled with variables! Humidity, temperature, fan. Out of the gun, distance from the surface, how much are you overlapping each pass? How fast or slow is your pass. Other than that paining should be easy right? Go look at any new car on the lot other than say a rolls Royce that is color sanded and you will see orange peel.

Always remember paints intended purpose - protection, not perfection. When apllied, the solids, protective qualities, etc rise to the surface.. as soon as a painter starts sanding & rubbing out, they're diminishing the qualities they paid the $ for! If not for "orange peel" golf balls would suck!.. You will be your toughest critic because you know what you weren't thrilled with, most people will only see the whole (pretty) picture!

Drying to fast use a slower drying thinner. Your thinner is to hot. Hardener can sometimes make it a little smoother and shine better. Good luck

So tell us your process are you using a system? What primer, are you spraying a tack coat or 3 r you putting a good flood on? Tell us as much as you can stand and a really good painter will probably know what your doing wrong, not me but someone will. good luck.

When I finish furniture I use sanding sponges made by Carborundum called EZ Touch. They come in various grits including 1500 and 2000 grit. They cut the paint fast and leave a surface ready to buff out by hand. Then the surface looks like a mirror, if you want the surface looking that shinny. They are an excellent product and you should be able to sand over the rivets without taking too much paint off them. Good luck, I really like your approach to perfection.

What Paint gun are you using ? HVLP, LVLP ?

I know you have finished it a long time ago but I am going to say it anyway unless you are going to pay someone else to wash and maintain the plain you need to lern how to buff it there might be some sallvont on the metal anyway keep up the good work you are lerning .

check your primer it may not be good if it comes off the easy

Paint it orange and name it "Sunkist".

Just a little something I found.

You need to verify that the other parts have good paint adhesion. That's your #1 issue. FORGET about the orange peal. That is NO problem compared to the adhesion issue.

PS.. you can look at www.carborundumabrasives.com Gord.

Thank you, John Cena.

Ignore the reference to clear coat--which you probably did not have. Professional detailers hate the idea of imperfect paint - as they should. They see orange peel, which is quite literally when your paint is textured like the skin of an orange, and they want to correct it. This requires smoothing the surface by wet sanding through the clear coat and pigment layer. If you read our last piece on over polishing, you’ll know we’re not the biggest fans of invasive paintwork correction procedures. This article will cover how your car becomes riddled with orange peel, how to fix it, and why I don’t really consider it to be that big of a problem for the everyday car owner. What exactly is orange peel? Put simply, orange peel is a textured imperfection in a paint job. You can see it with your eye because the paint is wavy in a sense, and reflects light in different angles around the imperfection(s). The surface will appear bumpy and won’t reflect perfectly. Often times you will find orange peel on panels that have been repainted. It can also come straight from the manufacturer in some cases. What causes orange peel? Not just what… it’s who, too. Orange peel is (in part) caused by improper painting technique - often by the manufacturer of the car or a body shop. According to Sherwin Williams, the orange peel effect has a few different causes. It can be caused by premature evaporation of thinner, incorrect spray gun setup (ie. low air pressure or incorrect nozzle), spraying at an angle other than perpendicularly, or applying excessive paint. 90% of the time, it’s human error. That explains why we often see the orange peel effect on high-end, hand-painted cars (Ferraris, Bentleys, etc.). How do you fix orange peel? You need to wet sand if the orange peel is bad enough. Sherwin Williams (and Dr. Beasley’s, for that matter) recommends starting with a compounding polish to see if you can address the problem without being too abrasive at first. If that doesn’t work, you should progressively get more aggressive as needed. Wet sanding, of course, is the dive-right-in approach that is most commonly used, but this makes my teeth cringe. Basically you wet the surface and the sandpaper, and diminish the clear coat until the surface is smooth. Then you follow with a polishing procedure to further smooth out the scratches you have created with the sandpaper. Because correction is an abrasive process in which you are removing microns of clear coat, in no way does this restore the finish to factory quality or thickness. If you want orange peel gone for good and your finish restored to factory-like condition (with a full clear coat), the area will have to be repainted. Hopefully it’ll be by someone with enough knowledge to ensure orange peel isn’t created a second time. Recap So now is when I rant about how correcting orange peel is essentially useless for the everyday car owner. Sure, if you’re a professional or are showing off your Duesenberg at Pebble Beach, orange peel might become annoying. But for most people, you either won’t notice it or won’t mind that it’s there. I ask if it’s really worth correcting, and again, many people will answer yes. But think about this: your brand new Benz has orange peel on the lower left quarter panel. It irks you that it’s there in the first place, but do you really want to remove the factory finish and pay a body shop $800+ to “do it’s ‘best'” to match and blend the panel? Or pay a shop to dig into your clear coat with sandpaper of all things and further diminish its thickness with a polishing procedure? Even without mentioning the money, I still don’t think correcting orange peel is worth it. It’s almost like getting a birthmark removed and expecting no scar. When it comes to paint, one way or another there always is. Yes, orange peel is fixable. My challenge to you is to question at what cost. In my opinion it’s much easier and more effective to polish the area and smooth out as much as you can without being too abrasive, then follow with a nano coating. This will essentially camouflage the blemishes, making them harder to notice. Try it out and let me know if it works for you… if not and you dive right in, I hope you post some before & after photos and tag us on Instagram!

Orange peel is simply the paint being sprayed too dry, it is not flowing out. Open fluid tip, move gun slower, hold gun closer, slower reducer, or more reducer. Adhesion to aluminum with primer problems. Most people think aluminum does not "rust" or in the case of aluminum, oxidize. Aluminum oxidizes immediately. Primer will stick to aluminum, but has poor adhesion to aluminum oxide. If you let bare cleaned aluminum sit for even a short time, it has already formed a thin aluminum oxide coat. Different paint companies have different treatments for bare aluminum. Pay close attention to getting the time between bare aluminum and a primer to an absolute minimum.

You didn't etch the surface before the primer!! That is aluminum painting 101! You don't need Alodine, but you need to etch the surface. Alumiprep.