Replies to This Discussion

Permalink Reply by John Austin on September 12, 2014 at 3:19pm

Although the 6061T6 is more resistant to corrosion than other alloys, likely the majority of builders use some form of corrosion protection. This seems to range from spraying the entire interior with zinc chromate (toxic stuff!) to just using it on mating surfaces. Zenith sells "Cortec," a supposedly environmentally friendly water-based primer. You can thin it with water to a brushable consistency and if not applied too thickly, it dries relatively quickly. Caleb told me it is OK to join mating surfaces while the Cortec is still wet,  but be careful since when it dries, it acts much like a glue and it can be difficult to re-position or remove parts after drying! (Don't ask me how I know! Ha!) The biggest criticism I have of Cortec is that once it dries, it is near-invisible and therefore easy to forget whether you've primed something or not ... wish they would dye it!

I'm in a moderate, temperate climate, so I chose to use the Cortec on mating surfaces. Someone planning to install floats and operate on salt water might opt for far more protection and someone in the desert might opt to use none at all!

John

N750A

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Permalink Reply by Anthony Polster on September 12, 2014 at 11:31pm

Thank you John for the information, I am just trying to put everything in order before order my kit.

I almost have my wood working shop re-laid out. I just finish making a 12 foot long work table. Trying to be ready before the kit comes. I will check out Cortec, because I don’t it to be ruin in, say 10 years.

Tony

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Permalink Reply by Bob Pustell on September 12, 2014 at 11:34pm

I live inland and not near a body of water. I plan to use a corrosion protector on joining surfaces only. At this point I have used and plan to continue use of Cortec for that purpose. As John has already pointed out, Cortec makes a dandy glue. This can be good news or bad news. As long as you are not gonna take that area apart it is good news. Otherwise, you have a problem. When I helped open up my friend's 601XL for the upgrade process we learned of the problem -- hard to get things apart. Even harder to get them apart without putting permanent creases into the aluminum. With care you can do it, but be careful.

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Permalink Reply by Anthony Polster on September 12, 2014 at 11:43pm

Hi Bob,

If Cortec was full dry before assembly, wound it vulcanize together?

Tony

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Permalink Reply by Mark Maltais on September 13, 2014 at 11:05pm

I'm not crazy about Cortec...

Every inch of my build is covered in Zinc Oxide or Zinc Chromate.  The Chromate is WAY better (it sticks better and won't scratch off, in fact overspray after it dries is almost impossible to get rid of, even with acetone or MEK!) but it's getting harder to find and expensive when you do + it's kinda toxic!!! :0

I bought Zinc Oxide in the gallon size and sprayed the skins and parts with an automotive sprayer.  Smaller parts that needed spraying as I went I used spray bombs.  The inspectors up here expect some kind of corrosion protection.  At the very least some form of protection should be sprayed on any surface that is mated to another! The spray bombs work well for this, and Zinc dries pretty fast. 

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Permalink Reply by Anthony Polster on September 14, 2014 at 9:14pm

Hi Mark,

Thank you for replying,

I am familiar with Zinc Chromate, and it is on HAZ Mat list. But allot items are now days. I am checking out what else is out there of airframes.

Thank you,

Tony

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