Ollie Krause
Well-Known Member
- Joined
- Feb 26, 2020
- Messages
- 103
Hi Home Built Airplane Enthusiasts,
I'm having some trouble figuring out the best practices for corrosion prevention in ultralight aircraft. I cam across this HBA thread which was super helpful but it primarily focused on sealant and less about broad corrosion prevention methods. I forget which HBA thread I read it in but I've also heard that some people simply don't take any action to prevent corrosion which may occur over the long term with the mindset that they won't own the ultralight by then. I'm in the process of designing (and hopefully later constructing) an ultralight with 15 other high school students and we'd like to do everything we reasonably can to prevent corrosion on our airplane for the learning experience if nothing else. Our truss frame is going to be constructed of 6061 T6 but a lot of our U brackets and other small structural components will 304 stainless or 4130 chrome moly. I noticed this isn't an uncommon practice and galvanic corrosion shouldn't become an issue as long as the steel parts are used sparingly and are relatively small. We also live in the San Francisco Bay Area which has a relatively low humidity but we'd ideally like our ultralight to be able to survive in the more humid environments down south. For regular corrosion, I would assume the the 304 stainless and 6061 T6 aluminum shouldn't be at much risk but the 4130 might have some issues despite it's improved corrosion resistance due to the molybdenum. This leads to three main questions:
1) How should I prevent corrosion where steel (stainless or otherwise) interfaces with aluminum gussets? I've read that zinc chromate primer is common but what paints do people typically use? What if these are moving parts which may scrape off any primer and paint?
2) How should corrosion be prevented on 4130 parts and the spring steel rear suspension?
3) I've noticed a couple ultralights use stainless steel rivets into aluminum parts. This should be okay since stainless steel is more cathodic but I was wondering if this practice should be avoided when possible.
Thanks in advance for any help!
I'm having some trouble figuring out the best practices for corrosion prevention in ultralight aircraft. I cam across this HBA thread which was super helpful but it primarily focused on sealant and less about broad corrosion prevention methods. I forget which HBA thread I read it in but I've also heard that some people simply don't take any action to prevent corrosion which may occur over the long term with the mindset that they won't own the ultralight by then. I'm in the process of designing (and hopefully later constructing) an ultralight with 15 other high school students and we'd like to do everything we reasonably can to prevent corrosion on our airplane for the learning experience if nothing else. Our truss frame is going to be constructed of 6061 T6 but a lot of our U brackets and other small structural components will 304 stainless or 4130 chrome moly. I noticed this isn't an uncommon practice and galvanic corrosion shouldn't become an issue as long as the steel parts are used sparingly and are relatively small. We also live in the San Francisco Bay Area which has a relatively low humidity but we'd ideally like our ultralight to be able to survive in the more humid environments down south. For regular corrosion, I would assume the the 304 stainless and 6061 T6 aluminum shouldn't be at much risk but the 4130 might have some issues despite it's improved corrosion resistance due to the molybdenum. This leads to three main questions:
1) How should I prevent corrosion where steel (stainless or otherwise) interfaces with aluminum gussets? I've read that zinc chromate primer is common but what paints do people typically use? What if these are moving parts which may scrape off any primer and paint?
2) How should corrosion be prevented on 4130 parts and the spring steel rear suspension?
3) I've noticed a couple ultralights use stainless steel rivets into aluminum parts. This should be okay since stainless steel is more cathodic but I was wondering if this practice should be avoided when possible.
Thanks in advance for any help!
