Corrosion

[barry_schaller]

Hi everyone. New to the group, but have admired your planes for a long time.

I recently bought an -8 emp kit off of Barnstormers. It was a good deal with all that I received, but there is light corrosion on some of the surfaces that will need to be addressed. I took the worst pieces to a local A&P and he said that the easiest thing to do is to Scotchbite and prime.

I was thinking of cleaning with Metal Prep Number 79 and then coating with Alodine 1201 (see Aircraft Spruce). If I do this, will I still have to prime the parts, or is the Alodine a corrosion proofing of it's own?

I am looking to do the quickest, easiest and cheapest method possible, with the least amount of space required. I know that I do not want to do a two part system. It may be better long-term, but am considering the Tempo spray primer method as an easier alternative. Thoughts? Has anyone used the Tempo stuff?

Thanks,
Barry

[Mike S]

Barry, welcome aboard the good ship VAF

Is the corrosion on the exterior surface or the interior?

If it is someplace that will eventually be part of the exterior, you coukd just take care of it when the plane is painted.

Many builders metal prep and alodine the parts, so that is a good option for you.

Good luck.

[John Tierney]

You could try a basic metal polish like Nevr-dull first, to see how bad the corrosion is. I had an issue with some mice a few years ago on my stored HS, and Neverdull took off most of the corrosion, but there were a few spots that needed more agressive treatment.
http://www.nevrdull.com/

[mike newall]

Think simple and you won't be disappointed.

The easiest way is, as your A & P suggested, scotch and prime.

A lot of the parts get bits of surface corrosion during the build, especially if they are set aside for a time as is likely.

Some of the worst bits are the edges of un worked panels still in the blue protection. Moisture gets in and the worms start !

Have a search for a product called Acid 8. It may be available in the US - it is a really good quality rattle can 1 part acid etch and is very useful for spot protection and for smaller parts that you don't want to mix a pot of primer for.

Failing that, I'm sure Spruce has similar.

The surface conversion products, while exceptionally good at what they do, can be complex, messy and contain some chemicals that you need to be very careful using.

[barry_schaller]

Wow ... Thanks for the quick replies, they have been helpful in deciding what I want to do. I am also glad to hear that I am not the only one to run into this issue. Mr. Newall is right on about where the corrosion is on the parts that were vinyl covered ... right at the edges where the vinyl peeled back slightly. There is also some on a few ribs, but all is surface and not a big deal, just annoying.

I have to prime the steel stuff anyway, so this would probably be the least amount of different things to get. If I do prime, I intend to just do a self-etching aerosol like the u-pol acid 8 or Dupont Dupli-Color. My question about those is, do you have to worry about the primer settling in the holes that you just drilled for rivets? Does it even make a difference.

I also did some more research on the alodine 1201/1001 and I am thinking that I might do it and not prime ... Thoughts? I thought that this might save a couple of pounds (probably more like ounces) when finished. Which is the better (read - more successful/less problems) method, immersion or wiping on?

What would Van's do?

Thanks again,
Barry

[Phil]

The Alodine is fine and you won't have any more problems where it's treated.

Give it a quick bath in the Metal Prep. ~ 60 seconds
Rinse it well.
Apply the alodine and let it setup.

Something to you might want to purchase for spot-jobs like this is an Alodine Pen. You can touch up trouble areas and can avoid some of the prep work of metal prep, primers, etc. Just hit it with the pen and let it dry. You can even force dry it with a quick hit of the heat gun if you're in a hurry. Works really well.

Phil