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

IMG_1556.jpgIMG_1557.jpgIMG_1558.jpg

[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.

IMG_3727.jpgIMG_3728.jpg

[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
PXL_20210814_210708341.jpg
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
PXL_20210814_210708341.jpg
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.