Whats this going to cost??

ChemGuy

ChemGuy

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ChemGuy
So I got together last night with 2 Co-Owners and after cleaning the bottom of our Dakota, this became much more visible. This looks like some deposits or corrosion along the right side of the belly. That is the side the exhaust is on. I am assuming its from the exhaust gasses, is that correct.

How do we fix this? How much? Plane is going into annual in a couple weeks. Should we address now or can we wait a few months after annual?

Thanks,
Dan
'79 Dakota



ndt17p.jpg



10sf1g2.jpg




116uusm.jpg
 
These pictures are after you cleaned and degreaser the area?
 
Yes. That was after we wiped with the gojo. Gojo and a rag wouldn't touch that.

Any ideas on how to remove those stains? Other sandpaper and paint? Its only on the exhaust side and tapers farther to the rear.

Dan
'79 Dakota
 
ChemGuy said:
Yes. That was after we wiped with the gojo. Gojo and a rag wouldn't touch that.

Any ideas on how to remove those stains? Other sandpaper and paint? Its only on the exhaust side and tapers farther to the rear.

Dan
'79 Dakota
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NEVER sandpaper! ask the A&P for recommendations. it may need to be chemically stripped, primed and then painted. Do nothing without talking to the A&P.
 
Most of this looks like it would have wiped right off with Gojo, I've had great success with that or the red Wash/Wax All. I'll be curious to see what the resolution is.
 
I also have had good luck with the heavy duty wash n wax product,give it a try then talk to your mechanic.
 
OK. I may try some better degreasers to see what they do to the stained portion.

The bumps look like corrosion starting to me, but could be lead deposits or ???

We will see what they say during the annual. I take it none of your planes have some issues like this along the exhaust side?
 
Whelp, just from the internetz pic, and without doing any real analysis - that looks like your standard filiform corrosion to me.

http://www.rustbullet.com.au/wp-content/uploads/2010/07/Filiform-Corrosion.jpg

Cost-wise it depends on how bad, and what an A&P says. I've had plenty of it that you just strip the paint, clean real good, put some anti-corrosion on and repaint. Other times, it's too deep and you are looking at a replacement skin.

Aren't you a chemist? You should know how this goes a lot better than us.
 
I suspected it might be corrosion, but I was hoping not.

That's what we get for cleaning the belly.....:D

I'll see what our A&P says.
 
One airplane on my field recently had a similar scenario--cleaned the plane, found something that looks similar to your photo. Their A&P told them it is corrosion and will need treatment. For them, it probably means a strip, clean, and repaint of at least the belly.
 
Straight SuperClean (by Castrol). Use an aggressive scrubbie -- the red ones.

Neutralize the SuperClean (which will eat aluminum, eventually) with any handy spray wax.

Then assess.

My guess is it's going to need a quick and easy prime then rattle-can paint. It's on the bottom, so it only has to pass the 10-foot rule.

Hint: Mask EVERYTHING. Ask me how I know. :)

EDIT: Wash your belly more often, and this won't happen!
 
Try to clean with wd-40 or mineral spirits... I didn't know about all this other crazy stuff to clean with??? GOJO????
 
Look, it's gonna cost ya a couple arms and a leg. Best thing to do is give me the 'kota and be done with it. It'll save you a bundle! :D
 
Jay Honeck said:
Straight SuperClean (by Castrol). Use an aggressive scrubbie -- the red ones.

Neutralize the SuperClean (which will eat aluminum, eventually) with any handy spray wax.

Then assess.

My guess is it's going to need a quick and easy prime then rattle-can paint. It's on the bottom, so it only has to pass the 10-foot rule.

Hint: Mask EVERYTHING. Ask me how I know. :)

EDIT: Wash your belly more often, and this won't happen!
Click to expand...

How does spray wax neutralize the highly alkaline SuperClean?
 
Went flying yesterday evening. A&P looks at it said wr will strip ut and clean corrosion off and paint.

Me and the other owners will try to do most of the work ourselves.

Sounds like ill be covered in stripper in a few weeks. And not the good kind of stripper....
 
Don't use that enviro friendly crap neither. It's useless. Get the 5 gal jugs of that slurry stuff and apply with a cheap paint brush.

To make even more work out of this, once you have the paint off, it's a good idea to get down to fresh metal. Sanding with 300 or 360 until it's no longer dull will help the corrosion inhibitor stick to the surface. You can use a DA, or a vibrating sander, just don't dig in, all you want to do is knock off the surface layer of oxidation. If you plane was originally coated with a corrosion inhibitor, you then must go back with a new coat. After you get it a bit fresh looking, avoid touching it with your hands, and get the new coating on it pretty quick. This is a humid time of year.
 
weirdjim said:
Yeah, well, watch out. The really good stuff (methylene chloride) will turn you into a girl without much hesitation.

Jim
Click to expand...

Methylene Chloride....bah. I bathe in that....look at my user name:D

I have drums of straight NMP at work. I may turn some into a gel for this job...:D
 
Thanks for the advice. Would you go over it with a scotch brite first/only or go straight to sandpaper, et al?

What paint do most of you use for touch up? Rattle can, ie Duplicolor grade or 2K catalyzed urethane in a touch up gun? Any particular paint systems to use or avoid?


docmirror said:
Don't use that enviro friendly crap neither. It's useless. Get the 5 gal jugs of that slurry stuff and apply with a cheap paint brush.

To make even more work out of this, once you have the paint off, it's a good idea to get down to fresh metal. Sanding with 300 or 360 until it's no longer dull will help the corrosion inhibitor stick to the surface. You can use a DA, or a vibrating sander, just don't dig in, all you want to do is knock off the surface layer of oxidation. If you plane was originally coated with a corrosion inhibitor, you then must go back with a new coat. After you get it a bit fresh looking, avoid touching it with your hands, and get the new coating on it pretty quick. This is a humid time of year.
Click to expand...
 
TUPilot said:
One airplane on my field recently had a similar scenario--cleaned the plane, found something that looks similar to your photo. Their A&P told them it is corrosion and will need treatment. For them, it probably means a strip, clean, and repaint of at least the belly.
Click to expand...

Lesson: Don't clean the belly of your plane! :D
 
3393RP said:
How does spray wax neutralize the highly alkaline SuperClean?
Click to expand...

It tells the SuperClean to go read some internet forums where a guy said so, and the SuperClean realizes it must be wrong and neutralizes itself! :rofl:
 
flyingcheesehead said:
It tells the SuperClean to go read some internet forums where a guy said so, and the SuperClean realizes it must be wrong and neutralizes itself! :rofl:
Click to expand...

Naaah. It is an alkaline solution and the best neutralizer for alkali is acid ... so spray it with battery acid afterwards.

Then call me. I specialize in tinbending.

Jim
 
Jay Honeck said:
Straight SuperClean (by Castrol). Use an aggressive scrubbie -- the red ones.

Neutralize the SuperClean (which will eat aluminum, eventually) with any handy spray wax.

Then assess.

My guess is it's going to need a quick and easy prime then rattle-can paint. It's on the bottom, so it only has to pass the 10-foot rule.

Hint: Mask EVERYTHING. Ask me how I know. :)

EDIT: Wash your belly more often, and this won't happen!
Click to expand...

How does the spray wax get into the skin' lap joints that the superclean has wicked into and where it will remain for a long time...eating the aluminum away?

God no! Never put that stuff on an airplane. Don't even allow it in your hangar. It will eat a hole through aluminum skin soaked in it for a week. A HOLE!
 
timwinters said:
How does the spray wax get into the skin' lap joints that the superclean has wicked into and where it will remain for a long time...eating the aluminum away?

God no! Never put that stuff on an airplane. Don't even allow it in your hangar. It will eat a hole through aluminum skin soaked in it for a week. A HOLE!
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LOL! Well, yes, you do need to use some discretion with any heavy duty degreaser. Do not spray it in unpainted seams, wipe it completely dry, and neutralize it with a good bath of spray wax. Then assess.

Then, if need be, move up to the strippers, alodine, etc.

It's all a PIA, but not difficult, unless the corrosion is uber-bad.
 
Jay Honeck said:
LOL!.
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Drop a piece of aluminum skin in a jar of that stuff. Pull it out a week later, rinse it off and tell me if you're still laughing then.

I've done it, it's not a pretty sight. When I say it'll eat a hole in it I'm not exaggerating in the least.
 
timwinters said:
Drop a piece of aluminum skin in a jar of that stuff. Pull it out a week later, rinse it off and tell me if you're still laughing then.

I've done it, it's not a pretty sight. When I say it'll eat a hole in it I'm not exaggerating in the least.
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Never said you were. But it's still funny that you think that has anything to do with what I posted.

Like I said, some discretion is required whenever using harsh chemical degreasers. Don't soak it for a week!
 
So your recommendation is to use a caustic solution on airplane skins with rivets and lap joints, then spray it with a wax?

:rofl:
 
ChemGuy said:
Thanks for the advice. Would you go over it with a scotch brite first/only or go straight to sandpaper, et al?

What paint do most of you use for touch up? Rattle can, ie Duplicolor grade or 2K catalyzed urethane in a touch up gun? Any particular paint systems to use or avoid?
Click to expand...

Well I guess whatever works to get oxidation off. I don't often use the scotchbrite but if it works thats fine.

I use the Dupont Imron system. Corrossion inhibitor or metal etch. Primer. Color coat. Its a bit more money but as long as you've gone this far, might as well do it up right.
 
Another source of corrosion on the belly of Cherokees is the battery box drain, also on the right side but starts under the rear seat.
 
3393RP said:
So your recommendation is to use a caustic solution on airplane skins with rivets and lap joints, then spray it with a wax?

:rofl:
Click to expand...
If you find a non-caustic, non-flammable, non-toxic degreaser that works worth a damn, let us know. I haven't found one.

I (and thousands, perhaps millions, of other folks) have used SuperClean as a degreaser on painted surfaces successfully for decades. Nothing works better, except EXTREMELY dangerous fluids like MEK, acetone, and 100 LL gas.

The trick is to dry the painted, cleaned surface as much as possible with rags, and then dilute any residue (once the grease is removed) to prevent any potential for damage. For this, a spray on liquid wax works well, but you could use just about anything, including water.

We've used this product on my four personally owned planes, and many motorcycles, over the last 15 years, without issue. My A&P (who taught me how to safely use SC) has done so for 45+ years.
 
In my crystal ball I foresee two A&P's drilling rivets, replacing skins and channels, painting, and walking away with a nice check in hand. :yes: :D
 
timwinters said:
GoJo
:thumbsup:
Click to expand...

And, BTW, GoJo, even if it was caustic, being the consistency of Jello, won't wick into your skin laps and eat away at the aluminum because you can't get it out. But it's not. I did the "soak a piece of skin in it for a week" test (actually 10 days) and found that the old dull skin was still just an old dull aluminum when I pulled it out.

Another very good cleaner, slightly caustic but not atomic like Castrol purple cleaner, is Dollar General's "Awesome" cleaner. It's indeed awesome and it only costs a buck.

TotallyAwesome.jpg


Gas stains, exhaust stains, etc. just melt away.

I did the "soak a piece of skin in it for a week" test (again actually 10 days) and found that the old dull skin was etched to a very bright piece of aluminum when I pulled it out. And then, once it sat out in the air for a week, I noticed some very slight pitting developing But it didn't come out black, pitted, mangled, with holes in it, and almost unrecognizable as aluminum...like a piece of skin soaked in Castrol did. Not even close. The Awesome treated aluminum almost exactly as Scrubbing Bubbles did when I tested it years ago.

I still won't use it on my plane but I'd sure rather see someone use Awesome than Castrol SuperClean.
 
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