Aluminum panel question...Does it need a finish

[Pirate]

I see that a lot of guys powder coat the panels. I plan on using Lizard Skin on the inside of the cockpit and the trunk so PCing those panels would be a waste. What about the panels in the engine bay? Does any of the aluminum need to be finished or will it be fine left alone? I do not live by the sea and it will not be driven if the roads are salted. I'm not really sure if they salt or just sand where I live, we don't get a whole lot of snow.

Thanks,

Chirs

[blueoval_bowtie_guy]

IMO, it is just a matter of personal preference. There are times when I'm at a car show that I really wish my aluminum looked better. My next kit I plan on coating what is visible (with hood / trunk / doors open).

[68GT500MAN]

I agree about it being a personal preference if you want to add color. My roadster has the bare aluminum in the engine bay and it still looks like when it was installed.
Doug

[sethmark]

Aluminum doesn't rust... but it does oxidize. That flat grey color you see is "rusted" aluminum. With that said, you can clear it, anodize it, paint it or powder it to keep it from turning. Beyond that its personal preference. I'm personally building a car to drive the doors off of, so its not as important to me. YMMV.

[MPTech]

I drove mine in gelcoat this summer and pulled the body off 2 weeks ago and all of the aluminum panels off last weekend.
I'm currently cleaning and sanding all of the engine bay panels, then giving them a brushed finish and applying Shark-hide to protect them before final assembly.

My aluminum panels weren't damaged, but they were not very good looking and you could see where I touched them with my fingers, the oil reacted and created permenant handprints from handling them.

[Ed Prokop]

For aircraft they etch then Alodine the surface. Etch with a diluted solution of Hydrochloric Acid (3 min). Rinse with water. Then add a solution of Alodine (3 minutes). Rinse again. The Alodine is a will give a slightly yellow surface appearance. It chemically seals the aluminum surface to reduce effects of corrosion. Find the Alodine at Aircraft Spruce or a similar kit plane builders site. Etching can help remove some fingerprints too.

I worked on a C-46 that was built in 1946 and the etch/alodine kept the surface in good shape all the was to 2001. It still had bullet holes that needed patching in the walk way floor. That took a doubler patch with rivets! Alodined it afterwards.

[CraigS]

Mine are unfinished and I admit they could look better. One problem w/ some kind of finish is that the inevitable scratch will need to be repaired some how. I saw a post somewhere from a guy who finished his w/ Rustoleum Hammered rattle can paint. I use this stuff a lot for brackets etc because it dries quite fast and I like the look. An advantage to it would be that a repair would be quick and easy and less noticeable than a repair of a full gloss paint. This is what I use. Not too far color wise from bare aluminum so scratches don't stand out.
http://www.rustoleum.com/product-catalog/consumer-brands/stops-rust/hammered-spray/
But I found this at the website
http://www.rustoleum.com/product-catalog/consumer-brands/auto/specialty-paints/hammered-engine/
Unfortunately only available in one color.

[blueoval_bowtie_guy]

For aircraft they etch then Alodine the surface. Etch with a diluted solution of Hydrochloric Acid (3 min). Rinse with water. Then add a solution of Alodine (3 minutes). Rinse again. The Alodine is a will give a slightly yellow surface appearance. It chemically seals the aluminum surface to reduce effects of corrosion. Find the Alodine at Aircraft Spruce or a similar kit plane builders site. Etching can help remove some fingerprints too.

I worked on a C-46 that was built in 1946 and the etch/alodine kept the surface in good shape all the was to 2001. It still had bullet holes that needed patching in the walk way floor. That took a doubler patch with rivets! Alodined it afterwards.

We were supposed to alodine whenever we put patch panels in Marine helicopters back in the 70's. It was always easy to tell whether someone got lazy and didn't do it. I often had guys get PO'd with me when I wouldn't sign off on their repairs. I told them to do it right and then I'd stamp the maintenance action form (MAF). It happened often and I'm still surprised when I hear (and see) the results when someone paints aluminum without treating it first. Another thing to keep in mind when refinishing aluminum is to never use steel wool or sandpaper on it. Use Scotch Brite. It won't imbed any particles in the aluminum that will create a corrosion problem later.

[edwardb]

The whole panel finish discussion is (like most other things about the build) all about what you want and ultimately want to pay for. Do you want a daily driver and don't care what's under the hood? Or will you go to an occasional car show and open the hood? Or are you going all out for show? You can leave the panels unfinished and that's what it will look like. You can use various surface finishes, paint, or powder coat. Just depends on what you want, and (as always) what you want to pay for. Both of my builds have been all powder coat, and I'm very happy I went that way. My Mk3 is silver, and looks like brand new still after two years on the road. Don't expect that will change. I'm not a serious car show guy, but have done a few and always looks great with the hood open. I'm working with a local powder coater on my Mk4. He quoted the same price whether he did all panels on all sides or only selective sides. So even though some get covered, all my aluminum is PC'd.

[Feen]

I am planning on doing the "hammered" silver paint for the reasons stated above. From what I have read, the guys who used it were happy with the outcome. Good looks, easy to repair and easy to install.

[mikiec]

It's called patina. My alum is as it was 13 years ago. Looks like it did when I built it.

Personal preference and budget. Your call.

[Avalanche325]

There is no need to coat them. It is just how you want them to look. I polished and Shark-hided my engine bay. It is very labor intensive.
http://i1061.photobucket.com/albums/t474/Avalanche325/IMG_0464_zpsaff540eb.jpg (http://s1061.photobucket.com/user/Avalanche325/media/IMG_0464_zpsaff540eb.jpg.html)