Milestone and Spar Cleaning / Corrosion Protection Question

[tim.green]

Hello Forum! I hope you're all having a great summer and getting some flying and building in.

Reached a big milestone on my Vixen build yesterday - mounted the rehabbed / completed right flaperon! (pics below). This is the result of a ton of work cleaning and repairing the flaperon, installing a customer tip and upgrading the flaperon attachment method to the model 7 hardware.

Question: I've cleaned the spars with simple green + microfiber and they're in good shape. Is it necessary to clean them further (say with a vinegar solution and red scotch write) or even etch, Alodine and prime them?

In particular I'm wondering if etching them with BONDERITE C-IC 33 AERO - ALUMIPREP 33 is safe / necessary and if so, should I Alodine and then prime them too? Any opinion on rattle can primers for such a task?

Thanks!

Tim

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[Jerrytex]

I used exactly what you have listed. My quick build wings were sitting in a barn for 20 years and had a lot of "cycles" of dust, and time on them so I ended up using red scotch bright pads on all the aluminum. Then used the Bondrite alumiprep. I will say that it cleaned a noticeable difference even after using the red scotch bright pads. I then alodined inside and out but it did not appear to work well. I have heard that alodine can be finicky and it was for me. I then used the 2 part epoxy in rattle cans. Takes 2 cans and works great. I sprayed the outsides of the spars after varnish. I taped off the cap strips and was careful spraying and they turned out good.

I will say that I also have/had a KF4 from 1992 and the spars on it were never coated with anything they look just fine after all the years, even with the oppressive humidity that we have here.

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[alexM]

Etch and Alodine is absolutely safe but you need to be able to rinse it really well. Kind of tough to do on a built up wing, especially if the ribs aren't varnished yet. From where you're at I would probably stick with the red scotchbrite pad, clean well with acetone and use the two part rattle can epoxy primer that Jerry suggests. I've got a couple fresh cans that just arrived here yesterday. That stuff sprays on better than I ever thought I would see from a rattle can.

I've come to the conclusion that I'm way more worried about the way the wood ages vs the aluminum. My Citabria had lots of both materials (and a lot of 4130) and I can tell you the aluminum was doing better than the wood in terms of fighting off moisture over a period of 5+ decades. To that end I have made epoxy varnishing my new hobby.

I did etch and Alodine every piece of aluminum before building my wings and that is where I'm going to stop.

[tim.green]

Alex and Jerry - Thanks! Great information! Super helpful - this forum always delivers!

Which specific primer are you guys using? Can you provide a brand or a link?

Thanks!

Tim


Etch and Alodine is absolutely safe but you need to be able to rinse it really well. Kind of tough to do on a built up wing, especially if the ribs aren't varnished yet. From where you're at I would probably stick with the red scotchbrite pad, clean well with acetone and use the two part rattle can epoxy primer that Jerry suggests. I've got a couple fresh cans that just arrived here yesterday. That stuff sprays on better than I ever thought I would see from a rattle can.

I've come to the conclusion that I'm way more worried about the way the wood ages vs the aluminum. My Citabria had lots of both materials (and a lot of 4130) and I can tell you the aluminum was doing better than the wood in terms of fighting off moisture over a period of 5+ decades. To that end I have made epoxy varnishing my new hobby.

I did etch and Alodine every piece of aluminum before building my wings and that is where I'm going to stop.

[alexM]

This stuff
28584
It's not cheap but it's a great product. You shake it up, insert a supplied plastic plug into the bottom of the can and press it in. This breaks the seal between the 2 parts (2K means two part I guess), shake it quite a bit more. Then you have something like 3 days to use it up. That time varies between the primer and the clear top coat they sell.
You can find it on Amazon if you can't find it at a local body shop.

[tim.green]

Thanks Alex. I ordered two cans just now! I appreciate your help!


This stuff
28584
It's not cheap but it's a great product. You shake it up, insert a supplied plastic plug into the bottom of the can and press it in. This breaks the seal between the 2 parts (2K means two part I guess), shake it quite a bit more. Then you have something like 3 days to use it up. That time varies between the primer and the clear top coat they sell.
You can find it on Amazon if you can't find it at a local body shop.

[JeffKinMT]

Do you guys plan to treat the inside of the spars? I'm getting close to this point in my build and have seen differing opinions...

[jiott]

Its really your choice and the mission and location of the plane. If you ever want to make a seaplane out of it, or if it will be based in humid or salt air environment, the I would say treating the inside is a must. Otherwise its just a personal choice of what makes you feel good. You have several choices of what to use: epoxy primer, alodine, etc. I used epoxy primer and tennis ball plugs to slosh the insides-fairly easy to do.