inner skin rust

[pinkflamingoes]

I saw a thread about dealing with inner skin white rust that is found when interior insulation is removed. I can't find the thread. I think I remember reading that it is a good idea to paint over the rusted areas or treat them somehow; any help out there?

Thanks

[boatdoc]

Originally Posted by pinkflamingoes

I saw a thread about dealing with inner skin white rust that is found when interior insulation is removed. I can't find the thread. I think I remember reading that it is a good idea to paint over the rusted areas or treat them somehow; any help out there?

Thanks

Hi Ingrid; There can be few reasons responsible for it. It is called oxidation and it can occur for different reasons. One is moisture. Two, dissimilar metals contact. Three, electrolysis. Four, stray currents, possibly bad grounding of something electrical in that area. Pending where it is and what it look like, repairing will encompass same procedure. Further prevention however, will depend on the original cause. There was a thread I believe started by Aerowood and titled Skin Corrosion to which I replied. See if you can find it. If not, Pm me with a pic of the area and I will try to help you. Thanks, "Boatdoc"

[CanoeStream]

Boatdoc, you make my life easy. Selecting 'Advanced Search' you get to enter search words and the posting member at the same time. I tell my computer illiterate mom that I can find the answer to anything online in two minutes or less. I only used 15 seconds, so you have a balance of 1.75 minutes left ....

http://www.airforums.com/forum...ion-26902.html
http://www.airforums.com/forum...sits-1269.html

Do not follow the advice about using glass beads or other blasting media -- it can permanently warp sheet aluminum!

[boatdoc]

Originally Posted by Canoe stream

Boatdoc, you make my life easy. Selecting 'Advanced Search' you get to enter search words and the posting member at the same time. I tell my computer illiterate mom that I can find the answer to anything online in two minutes or less. I only used 15 seconds, so you have a balance of 1.75 minutes left ....

http://www.airforums.com/forum...ion-26902.html
http://www.airforums.com/forum...sits-1269.html

Do not follow the advice about using glass beads or other blasting media -- it can permanently warp sheet aluminum!

Hi Canoe Stream; It is not I who recommended glass bead. I know much better than that, but thanks for the warning to others. Thanks "Boatdoc"

[CanoeStream]

Originally Posted by boatdoc

It is not I who recommended glass bead.

Just making sure that Ingrid doesn't get into trouble -- with that French champagne and all... . Just jealous here -- can you tell? I only briefly noticed bead blasting in one of the posts. I found out early on how walnut shell blasting peens aluminum and warps it -- on a small sample thankfully. Just because it gets posted doesn't mean that it's right!

[Aerowood]

I originally posted the "Skin Corrosion" thread. I am currently ready to replace the skin panel that I found corroded, as soon as the weather cooperates with my schedule. I have glass beaded alot of corroded aluminun parts in my carreer but not .032 skin. Most aircraft structure can tolerate 10 percent materail loss, under certain restrictions. It does not take much materail removel to be "out of limits" on thin structural skins. To effectivily remove corrosion from aluminum structure, it has to be removed from all mating components so the corrosion can be completly removed from all hidden areas. If the skin has to be removed for corrosion cleanup any way, you are money ahead in the long run, to just replace the entire skin. Replacement is the only way to garrentee all corrosion is gone, along with eliminating the cause of the corrosion in the first place. No need to replace or repair aluminum structure if the problem causing the corrosion is left in place. Cleaning up corrosion with brushes and scrapers will simply not work and the corrosion will return. The most effective way to repair skin corrosion is by replacment. I would not recomend that any exterior aluminum structure be reassembled without proper etching, alodining, then epoxy primming. Proper preperation before assembly almost eliminates the chances of corrosion ever returning in our lifetime.


Kip

[pinkflamingoes]

I am in the process of, as I stated in another thread, replacing the last freakin' window on the trailer. As soon as I get that done I'll post a picture. The area is mostly right where the wheel well was, so I'm thinking dissimilar metals. I took a look at Aerowood's thread, mine does not quite look like that but I'll post a picture and I'd love to hear what y'all think.

Thanks for the feedback, be back soon...

[pinkflamingoes]

Here's the picture of the area in question. Do I need to attend to this? If so how? It doesn't look like the "white rust".

It's the area where the wheel well was, inside the outer skin.

[Aerowood]

Its hard to tell from the picture you have posted. Could you post some other pics with closeup shots taken of worst areas. It looks like a real bad area just above the the left tire. The area just foward of the right tire at the "C" channel doesn't look happy either. 1001 posts cool

[Inland RV Center, In]

Originally Posted by pinkflamingoes

Here's the picture of the area in question. Do I need to attend to this? If so how? It doesn't look like the "white rust".

It's the area where the wheel well was, inside the outer skin.

Clean those areas that are oxidized.

Simply spray them with underseal.

Let the underseal totally cure out and out gas, then reassemble as you wish.

I did not see anything to worry about.

Andy

[pinkflamingoes]

I will post more pictures.

What exactly is underseal and where do I find it? I'm not too worried about this; I'm trying to find things to do while we save up for the purchase of some big items needed for the next step. MIght as well do something while I'm waiting!

[Inland RV Center, In]

Originally Posted by pinkflamingoes

I will post more pictures.

What exactly is underseal and where do I find it? I'm not too worried about this; I'm trying to find things to do while we save up for the purchase of some big items needed for the next step. MIght as well do something while I'm waiting!

Underseal or undercoating, is available from most auto parts stores as well as from Home Depot and the like. It comes in spray cans, just like paint.

It is an undercoating that has been used for 50 years or more on cars to protect them from the winter snow and salt.

It also does a nice job of sound deadening.

Andy