Paint touch ups (not for aesthetics)

[redbaron1982]

Hi all,

While a wait for my recenlty acquired M20J to get to it's new airport (now under annual, and then some major wing spar cap corrosion repair) I'm trying to make a plan on what I'm going to do it (when I'm not flying!).

Maybe because of this early experience with corrosion, and being the exterior paint not in great condition, I'm planning on doing some touch ups in all the areas where the paint is not ok. Main objective is to protect the aircraft, not to make it look great (although if I can make it look better it would be nice).

I would like to do it myself, in a step by step approach, not all at once. I have a few questions:

• Is scotch brite a good way of removing loose paint on aluminum?
• Is ok to paint over existing paint? I don't know how much weight it can add to have an additional coat.
• As long as I stay away from control surfaces, is this something I can do on my own without an AP signing anything?

My idea would be to, let's say take the left wing, go through all the areas where the paint is not ok, clean up the area, use scotch brite or similar to smooth the area and remove loose paint, treat the aluminum, and then paint over. I'm also evaluating paint the whole wing, just to improve the look. Then, at other time, move to the other wing. Then cowling, an so forth.

At some point I would also do control surfaces, and for that I will get an AP to assist on removal, reinstalling and rebalancing them.

So, what are you thoughts? Is this a good or bad idea? I know that sending the aircraft in for a full stripping and paint job is the ideal in term of results, but at this point I'm on a budget and don't want to spend north of 10k on this.

[Danb]

I stripped the paint, primed it with approximate  primer, took panel to paint shop for color match, painted, blended, was the toughest part. Was well worth the effort. For minor stuff I touch up with camel hair brush. 

[redbaron1982]

6 minutes ago, Danb said:

I stripped the paint, primed it with approximate  primer, took panel to paint shop for color match, painted, blended, was the toughest part. Was well worth the effort. For minor stuff I touch up with camel hair brush. 

Hey, that looks great! So, we could say that is the result of an "amateur" job? Don't misinterpret it, it looks really good. Just one to understand if that's the result of a paint shop work or not.

[Danb]

14 minutes ago, redbaron1982 said:

Hey, that looks great! So, we could say that is the result of an "amateur" job? Don't misinterpret it, it looks really good. Just one to understand if that's the result of a paint shop work or not.

Yep, trial and error, the first section I messed up the hardener and had to strip if off again, an extra 8-10 hours of incompetence. Now I know how to do it. YouTube is invaluable 

[ArtVandelay]

Yep, trial and error, the first section I messed up the hardener and had to strip if off again, an extra 8-10 hours of incompetence. Now I know how to do it. YouTube is invaluable 

What kind of paint did you use?

[Danb]

Jeez I can’t remember, it’s in the hanger, it was a two part paint I think four part to one, I think the primer was by SEM. When I get to hanger I’ll look.

[EricJ]

6 hours ago, redbaron1982 said:

Hi all,

While a wait for my recenlty acquired M20J to get to it's new airport (now under annual, and then some major wing spar cap corrosion repair) I'm trying to make a plan on what I'm going to do it (when I'm not flying!).

Maybe because of this early experience with corrosion, and being the exterior paint not in great condition, I'm planning on doing some touch ups in all the areas where the paint is not ok. Main objective is to protect the aircraft, not to make it look great (although if I can make it look better it would be nice).

I would like to do it myself, in a step by step approach, not all at once. I have a few questions:

• Is scotch brite a good way of removing loose paint on aluminum?

Yes, and there are many different types of scotch brite that essentially equate to different coarseness of sandpaper or steel wool.   They're all fine for use on aluminum.

6 hours ago, redbaron1982 said:

• Is ok to paint over existing paint? I don't know how much weight it can add to have an additional coat.

Yes.   

6 hours ago, redbaron1982 said:

• As long as I stay away from control surfaces, is this something I can do on my own without an AP signing anything?

Yes, paint falls under "decorative coating" and is considered preventive maintenance.    And, yes, control surfaces are essentially considered separately due to balance requirements.

6 hours ago, redbaron1982 said:

My idea would be to, let's say take the left wing, go through all the areas where the paint is not ok, clean up the area, use scotch brite or similar to smooth the area and remove loose paint, treat the aluminum, and then paint over. I'm also evaluating paint the whole wing, just to improve the look. Then, at other time, move to the other wing. Then cowling, an so forth.

At some point I would also do control surfaces, and for that I will get an AP to assist on removal, reinstalling and rebalancing them.

So, what are you thoughts? Is this a good or bad idea? I know that sending the aircraft in for a full stripping and paint job is the ideal in term of results, but at this point I'm on a budget and don't want to spend north of 10k on this.

Many of us do this sort of thing regularly, especially after repairs or minor alterations.    Finding a good match for paint colors can be tricky, and many automotive paint supply stores can mix color to match, and even put it in a spray bomb for you. 

A friend has a Brazov IAR823 that is painted in a camouflage scheme that looks pretty cool but is essentially just patches of different common primer colors.   It's really easy to do touch-ups and repaint pieces on that. 

[A64Pilot]

A few comments, first the aluminum is Alclad, meaning it has a very thin layer of pure aluminum on it to help prevent corrosion. So be as gentle as possible with prep so as to remove as little of the pure aluminum as possible.

https://en.wikipedia.org/wiki/Alclad

Then any bare metal should be Alodined, Alodine is another corrosion preventative. Alodine also improves the paint bonding to the skin

https://www.besttechnologyinc.com/surface-finishing/what-is-alodine-chem-film-chromate-conversion-coating/

https://www.aircraftspruce.com/catalog/cspages/alodine1201.php?clickkey=11999

Corrosion that keeps showing up at seams may well be from previous paint stripper use that wasn’t neutralized, Stripper gets wicked in the seam, so be careful with it and be sure to neutralize it when done if you use it.

Painting over old paint is fine especially on small areas, if the underlying paint has good adhesion.

I’ve not met a painter that had their A&P, whatever that’s worth, but I’m sure many A&P’s do small paint work

Edited February 1, 2022 by A64Pilot

[redbaron1982]

Hey! Thanks all for the feedback! It's reassuring knowing that I don't have dumb ideas! I think with the comments here I will go more with the stripping option more than the physically removing the paint.

As of color matching, the wings (most concerning part right now) are all white, so I although I  need to match the right white anyway, it's not as hard as a more complex pattern

[PT20J]

7 hours ago, Danb said:

I stripped the paint, primed it with approximate  primer, took panel to paint shop for color match, painted, blended, was the toughest part. Was well worth the effort. For minor stuff I touch up with camel hair brush. 

How did you blend it?

[Danb]

9 hours ago, PT20J said:

How did you blend it?

I sprayed it past the area that needed the paint maybe 10-12 “ after it set up I used various sand paper  500, 800, 1000. Then compounded it. I still have to do some more had an area of orange peel that needs some more loving. This spring I plan on doing the white. It’s rather enjoyable doing it. Not being mechanically inclined it’s fun doing this stuff

[redbaron1982]

I have one more doubt I forgot to mention, my mooney has TKS, what's the correct way to protect it will doing this touch ups? I read that they are quite sensitive to clogging. I'm sure regular masking type my not be a good idea to cover the TKS on the leading edges.

[ZuluZulu]

On 1/31/2022 at 12:26 PM, Danb said:

I stripped the paint, primed it with approximate  primer, took panel to paint shop for color match, painted, blended, was the toughest part. Was well worth the effort. For minor stuff I touch up with camel hair brush. 

Can your hangar elves meet mine?  Maybe some kind of seminar or something?

[Mark89114]

8 hours ago, redbaron1982 said:

I have one more doubt I forgot to mention, my mooney has TKS, what's the correct way to protect it will doing this touch ups? I read that they are quite sensitive to clogging. I'm sure regular masking type my not be a good idea to cover the TKS on the leading edges.

I put delicate painters tape on it, not the old blue stuff.  The delicate painters tape is in the same aisle as the regular.  I was just doing a bunch of compounding and heavy cleaning/waxing and wanted to keep out and off of the TKS panels.  

[EricJ]

21 hours ago, redbaron1982 said:

Hey! Thanks all for the feedback! It's reassuring knowing that I don't have dumb ideas! I think with the comments here I will go more with the stripping option more than the physically removing the paint.

As of color matching, the wings (most concerning part right now) are all white, so I although I  need to match the right white anyway, it's not as hard as a more complex pattern

One caveat on stripping is to avoid the fuel tank areas.   Stripper can penetrate the seams and get behind the sealant inside the fuel tank and separate it from the tank surface.   

 

[redbaron1982]

1 hour ago, EricJ said:

One caveat on stripping is to avoid the fuel tank areas.   Stripper can penetrate the seams and get behind the sealant inside the fuel tank and separate it from the tank surface.   

 

And how you avoid that? Just not using stripper on the seams and removing the paint with scotch brite or something similar?

[EricJ]

16 hours ago, redbaron1982 said:

And how you avoid that? Just not using stripper on the seams and removing the paint with scotch brite or something similar?

Some videos posted by people getting recent paint jobs shows the shop taping off seams everywhere, not just at the tank, prior to stripping.   I don't know whether that's universal or specific to the stripper used or specific shops, but it's definitely something to watch out for.

[Jcmtl]

I'm curious about this as well.  

For touchups to the wing leading edge where the paint has completely come off, what is the best DIY solution? 

Are there any good 2 in 1 primer paint sprays?  if so, which ones?  Etch primer or non etch primer?  

Thanks!

[Danb]

1 hour ago, Jcmtl said:

I'm curious about this as well.  

For touchups to the wing leading edge where the paint has completely come off, what is the best DIY solution? 

Are there any good 2 in 1 primer paint sprays?  if so, which ones?  Etch primer or non etch primer?  

Thanks!

Yes there is, a custom auto paint shop, can match the colors, provide various type primers and can either put in spray cans or regular cans. They can be two part where you press a button on the bottom of the spray and shake it up, then must be used within a few hours or so

[A64Pilot]

4 hours ago, EricJ said:

Some videos posted by people getting recent paint jobs shows the shop taping off seams everywhere, not just at the tank, prior to stripping.   I don't know whether that's universal or specific to the stripper used or specific shops, but it's definitely something to watch out for.

Sounds like a good shop to me, I’ve only painted one or two and didn’t tape off seams, but did neutralize the stripper and use a pressure washer in an attempt to clean out the seams, I’m sure taping them off and making sure no stripper gets wicked in is better.

At Thrush as it’s an Ag plane and many chemicals are corrosive, every seam was sealed with fuel tank sealer prior to painting, just a very thin line, but it does seal the seam, and isn’t visible once painted.

[redbaron1982]

5 minutes ago, A64Pilot said:

Sounds like a good shop to me, I’ve only painted one or two and didn’t tape off seams, but did neutralize the stripper and use a pressure washer in an attempt to clean out the seams, I’m sure taping them off and making sure no stripper gets wicked in is better.

At Thrush as it’s an Ag plane and many chemicals are corrosive, every seam was sealed with fuel tank sealer prior to painting, just a very thin line, but it does seal the seam, and isn’t visible once painted.

Fuel tank sealer would be the POR 15 fuel tank sealer?

[Fly Boomer]

Has anyone sprayed with conventional or HVLP?  Anyone used an airbrush?

[EricJ]

20 minutes ago, redbaron1982 said:

Fuel tank sealer would be the POR 15 fuel tank sealer?

No, there are specific FlameMaster or PRC blends approved in the maintenance manual for the tanks, if that's what you're asking.   There are different formulas for the seam sealers, panels, and topcoat.

 

Edited February 2, 2022 by EricJ

[Danb]

1 hour ago, Fly Boomer said:

Has anyone sprayed with conventional or HVLP?  Anyone used an airbrush?

Used an HVLP on my wings 

[Fly Boomer]

@Danb I'm confused by the wing pics.  Most are without TKS, but one has the TKS leading edge.  Are these taken at different times?