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Peeling/flaking paint touch up

M

mmahony1

Member
I have an RV12 that is now about ten years old and paint has started peeling along the seam between two sheets of skin on the upper tailcone/rear fuselage - see pic for clarity.

There are a couple other spots where paint is a little rough but I don't want to shell out $10k+ to have the whole plane repainted.

What are my options to touch up areas where paint has peeled and stop it degrading further? What do I need to look out for when buying products that are aluminum safe? Any other caveats to keep in mind?
 

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From the picture it appears that the aircraft was not properly prepped for paint. Preparation is the MAJOR part of painting. Paint should not peal up showing bare metal. Is there any sign of primer on the bottom side of the pealed paint? There is none showing where the paint is gone. If the aircraft was painted without proper preparation, there is nothing you can do but strip it and start over. Pealing WILL continue!
 
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Possible poor deburring and edge prep. Possible poor surface prep.

= bad paint adhesion.

Good paint job done right can last 60 years and if the aircraft is hangared.

Cut corners, reap the results. Applies to all things in life.

Proper surface prep is Painting 101.

Any coating or paint is only as good as ITS WEAKEST LINK.

Surface prep, surface prep, surface prep.
 
Depending on how widespread the peeling is, the repair could be fairly straightforward or involved and time consuming. Like the others have said, the surface prep wasn’t the best.
 
mmahony1 said:
What are my options to touch up areas where paint has peeled and stop it degrading further? What do I need to look out for when buying products that are aluminum safe? Any other caveats to keep in mind?
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You can always do touch up with automotive spray paint. You need to peel off the area with bubbling paint and sand down the paint edge. You may need to apply light weight Bondo or equivalent to fair in the edge. Shoot automotive epoxy primer which is 100% on aluminum. Then apply automotive top coat, single stage or double with a gloss coat. There is a technique to incrementally overspray the repair area to mask the defect area but from your original question, you aren't probably ready for it.

In the end, what is the goal? If it is to maintain a decent weather protection, then the technique above should work. If you want a show quality result then consult a professional.
 
Thanks Phat, this is the kind of info I’m after. My intention is just to protect the airframe and prevent corrosion. I’ll look into this process more.

Everybody else, thank you for your input. I appreciate the importance of prep work and can’t speak with any detail to how it was originally done. Regardless, a $10k - $15k capital outlay isn’t something I’m inclined to embark on if a touchup can get the aircraft to equal or near equal corrosion protection.
 
hard to tell from a pic, but it doesn't look like there was primer under the paint. We use primer first, as it has a stronger bond to metal. Looks like single stage was shot directly onto the alum. If that was the case, this is just the beginning of problems. That step joint creates weakness for the paint, so a crack starts there. Once it cracks, if there is a poor bond, the cohesive sheet of paint starts to lift off the metal. In the pic, you can see a very large bubble shape where the paint has delaminated from the surface. You can expect more of that over time. Hope I am wrong here.
 
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Ok, I went back out to the airport and can confirm that there is a grey primer on the underside of the paint chips. The paint is coming up along the seam pictured and generally has good adherence within an inch of it. In a couple of spots it extends a little further outwards.

I’m getting some chips color matched this week and will prime again and feather against the old paint.
 
The original grey primer was possibly not suitable for aluminum, or the surface was not prepared properly.

There will now be a good layer of oxidation to remove before applying the new primer. If epoxy, as Phat suggests (I agree) then the aluminum will need to be scuffed up per the primer manufacturer technical data sheet. Also check the top coat paint is compatible with the primer, so you only need to do this once.

Color matching is difficult on an old surface so another idea is to use a contrasting color e.g. white or another color, for some additional stripes, rather than try to blend it in. It depends what the overall color scheme looks like.
 
Sometimes the seams can get contaminated with sanding dust or even cleaning -prep solvents. The pictures of the priming and painting process the builder did appear to be correct so it could be something in the seam. Good luck. It looks like a nice paint job - except for the bad part!
 
rockwoodrv9 said:
Sometimes the seams can get contaminated with sanding dust or even cleaning -prep solvents. The pictures of the priming and painting process the builder did appear to be correct so it could be something in the seam. Good luck. It looks like a nice paint job - except for the bad part!
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I have a different opinion. I had a 6-12" area on my 6 where the paint cracked at the seam. However, the lifting stopped about 1/2" from the seam and has not progressed. Clearly I did something wrong there to cause the cracking (think I got the paint too thick in that area). However, the now unattached sheet of paint IS NOT lifting from the rest of the surface, even with the 180 mph airstream acting on it. THe OP pics are MUCH worse than mine and show a great deal of de-bonding well past the seam. I unfortunately believe there are some issues with the prep work for the OP's paint job.. When the paint is well bonded to the metal, cracks or chips should not create any de-bonding past the damage area.
 
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PaulvS said:
Color matching is difficult on an old surface so another idea is to use a contrasting color e.g. white or another color, for some additional stripes, rather than try to blend it in. It depends what the overall color scheme looks like.
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That's an idea. For prep if I went this route would I need to remove all old paint under this strip, even if it has good adhereance? Or just clean it with a prepaint solution?
 
mmahony1 said:
That's an idea. For prep if I went this route would I need to remove all old paint under this strip, even if it has good adhereance? Or just clean it with a prepaint solution?
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If the old paint is sound and has good adhesion then it does not need to be removed. It would be worth checking on a small area first to ensure the new paint is compatible. A good way to test the adhesion of the old paint is to apply some heavy duty duct tape then rip it off.

Typically the old paint would be degreased with degreasing fluid e.g. naptha and then sanded 350-400 grit dry or 600 wet (per instructions for the paint that is going over the top).
The epoxy primer can probably go over both the scuffed up aluminum and the old paint, and then the topcoat over that. The area would be masked off from the rest of the plane.
The paint shop should be able to help with the correct combination of products.
 
Decals? Graphics?

You could try some vinyl graphics and/or 3M wrap to cover those places. Get creative, more color, you might even like it. (Make lemonade?…)
 
Prep

PaulvS said:
If the old paint is sound and has good adhesion then it does not need to be removed. It would be worth checking on a small area first to ensure the new paint is compatible. A good way to test the adhesion of the old paint is to apply some heavy duty duct tape then rip it off.

Typically the old paint would be degreased with degreasing fluid e.g. naptha and then sanded 350-400 grit dry or 600 wet (per instructions for the paint that is going over the top).
The epoxy primer can probably go over both the scuffed up aluminum and the old paint, and then the topcoat over that. The area would be masked off from the rest of the plane.
The paint shop should be able to help with the correct combination of products.
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What he ^ said. Gorilla tape. Rub a section down. Leave it over night. Rip it off.

My opinion, that looks like the aluminum wasn't prepped correctly. I've seen paint I could peel off aluminum panels (not airplanes) in big sheets. Aluminum oxide must be removed and the surface treated as soon as possible with Alodine or a wash primer or both. Then a 2K epoxy primer before final paint. Again, my opinion.

I bet it's a localized area and the rest is probably fine. Remove it back to where it's viable. Feather the edge. Prep the bare area and apply some paint. Then either shoot matching paint or add some vinyl graphics.
 
mmahony1 said:
I have an RV12 that is now about ten years old and paint has started peeling along the seam between two sheets of skin on the upper tailcone/rear fuselage - see pic for clarity.

There are a couple other spots where paint is a little rough but I don't want to shell out $10k+ to have the whole plane repainted.

What are my options to touch up areas where paint has peeled and stop it degrading further? What do I need to look out for when buying products that are aluminum safe? Any other caveats to keep in mind?
Click to expand...
If you 'only' had to shell out $10gs to repaint it, act fast! That would be stealing. Cost to repaint an RV should be closer to $30gs, not including the stripping.
 
rockitdoc said:
If you 'only' had to shell out $10gs to repaint it, act fast! That would be stealing. Cost to repaint an RV should be closer to $30gs, not including the stripping.
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$30k to paint not including stripping? Holy crud! I would do it for a lot less than that.
 
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