Greg Arehart

Greg Arehart

Well Known Member
I am considering anodizing my panel rather than painting. Anyone have experience with this? Is it a good or bad idea?

Thanks,
greg
 
panel treatment

I've seen pictures of an anodized panel. Very gold and nice looking but I thought it would be too reflective when in sunny conditions. I think powder coat is the best but I will likely paint a dark matt colour.

Bevan
 
I've always wanted a charcoal gray anodized panel with the kind of brushed finished you find on good cookware pots and pans. The are not reflective at all, and the anodized surface is very hard and damage resistant. Anyone know who can provide this service?
 
Bevan,

I am not thinking gold (were you thinking alodine?) but rather the matte black to very dark grey that is what comes with the quadrant throttles. I have been building a panel extension to incorporate the quadrant (wife is also a pilot and wants some control she can reach from the R seat) and expect to anodize this also.

Ron,

I just looked in google and found a local shop (Apex Anodizing) that seems able to do this kind of work. I have not spoken to them yet to determine whether they are willing to do a small order. I think typically these guys do architectural work. Will keep you posted when I find out.

greg
 
Try bead or sand blasting.

Another thing for a "matte" finish is sandblasting the panel then anodizing. I'm doing a military scheme and the panel will be done in a matte black. You can play with a scrap piece of aluminum and alodine to see how different blasting media works...it is kinda fun in a weird way. Plus the finish is really flat (not shiny) Paint works just fine, but it is fun to try something different. Dings and be touched up with a Sharpie. :rolleyes:
 
FWIW

Just a point of info to consider.

If You go with anodizing----------it is electrically insulating.

You will need to pay attention to your grounding.

Good luck.
 
Just a warning to watch out--I'm not an expert on this.

Sandblasting is generally not recommended for aluminum--it will tear it up pretty fast. There are other media that might work and should be used on aluminum instead of sand. Any of them will probably go thru the alclad pretty fast and I suspect that if some alclad is left it will anodize differently from the other areas.


Richard Scott
RV-9A Fuselage
 
Avoid 2024

If you decide to anodize, be kind to your vendor and don't use 2024 sheet. It has copper in the alloy and it polutes their dip tanks. It also may not anodize with an even color due to the alloying elements.

6061 is A-OK.

If you want excellent scratch resistance, ask for "hardcoat" anodizing. Effectively Rockwell C 70 from a scratch resistance standpoint (In laymans terms, this is REALLY hard, like cylinder liner). It will be dark green to black color. More commonly dark green in my experience.

Also, it will NOT cover surface imperfections, but rather will encase them in an impervious picture frame for all to see. :eek: I like a smooth matte finish on the bare part before having it anodized. Smooth corners and radii are better for the process too. It can chip away from sharp edges.

Now for the bad part. On thin sections, the converted surface may have somewhat less crack resistance because of the base metal flexing. I personally have not used anodizing on sheet products, only heavy wall sections that maintain their shape.

If you remember back to rivet squeezing on the anodized spars supplied by Vans, you may recall the brittle "scrunching" sound during the squeeze. This is an example of the surface brittleness I am refering too. The spars are thick enough so this is not an issue. A panel may be different.

Even with that caveat, I may coat mine too. Let us know how yours comes out if you decide to do it.
 
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Rivets too?

Thanks to all who have provided information and opinions. So here is what I found out from my local anodizer. Cost for a panel and several other smaller pieces will be less than $100, probably more like $70. Seems reasonable, though obviously more expensive than paint. Time is not an issue - they said less than a week to do the job, unless I want some sort of unusual dye color. Surface imperfections (as noted by some of you) will definitely not be covered, and will be just as visible or more so after anodizing. One consensus of our discussion was that the finish on the anodized panel will be similar in gloss to the original finish, thus I am expecting to scotchbrite or beadblast the panel to produce a more satin or matte finish.

I have already riveted on the stiffener at the top of the panel, and that Al angle was primed, so I will either have to beadblast the surface to remove the primer or drill out the rivets, just anodize the panel, and rerivet the stiffener on. Which leads me to the question of the composition of rivets. As a number of you have noted, chemical composition can affect the final color etc, so if the rivets are of a different composition than the alclad, they may come out differently (one argument for drilling them out before anodizing) and may? cause other adverse chemical reactions locally on the panel. On the other hand, having the rivets already set would allow for a very smooth finish where the rivets will hardly be noticeable (presuming there is not a chemical difference that would cause color differences). So, does anyone off the top of your head know the composition of rivets as compared to 6061? I suspect there may be a chemical variability in rivets as well, because some are softer than others.

In the end, I may just try a couple of things and see what, if anything, works.

greg
 
Greg,
I would avoid anodizing assemblies because it is hard to rinse the process acid out from between the mated parts.
 
I believe rivets are 2117, so a copper alloy, in 6061 magnesium is used as the main alloying element. No idea how that affects the anodizing.

Pete

2117
Aluminum Balance
Chromium 0.1 max
Copper 2.2 - 3
Iron 0.7 max
Magnesium 0.2 - 0.5
Manganese 0.2 max
Remainder Each 0.05 max
Remainder Total 0.15 max
Silicon 0.8 max
Zinc 0.25 max

6061
Aluminum Balance
Chromium 0.04 - 0.35
Copper 0.15 - 0.4
Iron 0 - 0.7
Magnesium 0.8 - 1.2
Manganese 0.15 max
Other 0.15 max
Remainder Each 0.05 max
Silicon 0.4 - 0.8
Titanium 0.15 max
Zinc 0.25 max
 
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Panel update

Here's an update on the panel anodizing. I drilled out the rivets and removed the upper angle backing, so the panel was just a sheet of alclad. I decided I wanted a matte-like finish and after talking with the anodizing guy, scuffed the entire face with grey scotchbrite to minimize the glossiness. He also told me that every little scratch would be visible (i.e., anodizing doesn't hide anything). As planned, I had the pieces (including some console parts I was building) anodized black and they came out fantastic (in my opinion). As noted in some previous threads, there are a couple of small areas that are slightly different in texture/color, but virtually unnoticeable unless pointed out. The back of the panel was not scuffed, so I am able to compare the glossy vs matte finish, and I much prefer the matte. The glossy finish is indeed fairly reflective (as noted by some others), and I could see (pun intended) the potential problems in the cockpit on a sunny day. The matte finish is still more reflective than a flat black paint - I would compare the finish to what the painters call "satin." FWIW, I did this before making any cuts on the panel, so that may have helped in getting a good consistent finish (I don't know this, just speculating because of the possibly different electrical potential across the sheet). It should also help with the conductivity (ground) when I install instruments because the cut edges will be conductive.

All in all, I am happy with the results thus far. I'll try to post some photos if I can get ones that show more than just black...

Cost was $75 for 5 pieces (panel by far the largest). $45 of that was setup charge, and $30 for the actual work. I probably could have done several additional panels for only a few $ apiece. Took about a week.

greg
 
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