Joint compound advice Cor-ban

Just wondering if anybody has used cor-ban 27l corrosion inhibitor for joints and if so what their experiences are with it? Seems JC5A is used by many builders but is cor-ban 27l a suitable alternative?

I?ve been wondering the ame thing and asked the group back in November to no avail.

You probably would have got the same answer then as now.....

No need !

Vans supplies nearly all steel powder coated where there may be a problem, where not powder coated, you will be priming the parts before assembly and therefore eliminating any potential problem.

Both products are vile to use and very old fashioned.

Build on dry your aeroplane will outlast you

Typically you'll find things like Cor-ban (and its even nastier predecessor Mastinox) used in places where you're going to get a lot of moisture exposure and otherwise have really corrosive environments, and the items in question are things that need to be able to come apart again. These compounds don't harden like sealants do so you are able to undo the sealed items.

On large aircraft you'll see it used on bolts, nuts, etc. on major landing gear fittings, like the giant castle nut that holds the wheels on or the bolts that retain the trunnion pins. You might also see it on the hardware at control surface hinges. It keeps the threaded parts from seizing and keeps water from seeping into the separable joints and corroding things there.

On a small aircraft you're probably better off just using a good thick grease at such locations, and keeping your aircraft hangared. Most of us aren't typically going to be flying in poor, icy weather with lots of deicing fluid.


Now, if you want to fay seal steel vs. aluminum in a permanent joint, you could just use a little leftover fuel tank sealant--it won't hurt anything. There's a similar sealant (MIL-PRF-81733, aka PS 870) that's more corrosion inhibitive but for our purposes tank sealant will keep the water out and that's good enough.


EXCEPTION: Don't use any of these on fluid connections (fuel, brakes, etc.). Only use proper sealants there!


TLDR: If you want to use something, use grease on separable joints and tank sealant on permanent joints. Cor-ban and similar stuff is expensive and nasty.

Thanks for the info and opinions, it?s much appreciated. I?m based in a damp Uk and finding hangar space is both difficult and expensive. Of course I plan to keep the aircraft always hangared but if it?s going to have any periods outside during the summer, I want to know that I?m taking every precaution I can during the build to help prevent corrosion.
Obviously in an ideal world, she?ll always be hangared, but just in case.....