cjensen

cjensen

Well Known Member
Will MEK hurt the anodized finish of the spars? I have some primer and paint overspray that I'd like to clean up a bit, and MEK should do the trick...but I don't want to hurt that finish. Far as I can tell, the anodizing is a surface treatment, not a coat, so it shouldn't do anything, correct? :confused:
 
Anodizing is a surface treatment. When you anodize, what you are doing is forcing the outside couple of mils of aluminum to oxidize (corrode) in a controlled fashion. This layer of aluminum oxide, known as alumina is actually a ceramic. A very good, hard ceramic. It's one of the reasons that aluminum is such a miracle material. It's self protecting. That's why your skins are Alclad--the pure aluminum on the surface is self protecting.

To answer your specific question. MEK will not hurt the anodize. However, the gold color is a result of dying the alumina coating after the anodize process. The MEK may lighten the dye a bit.

In other words, MEK has a small chance of changing the color, but it won't harm the coating on your spars any more than it will hurt a coffee cup.

Regards,
Guy
 
Great, thanks Guy! Not concerned about a small color change. Just want to remove some of the overspray.

3-26-07001w.jpg
 
Chad:

The overspray is on hidden structure. Just leave it and you'll gain extra corrosion protection :D

Jekyll
 
I know, but it's messy, and I don't like leaving things messy. If I don't clean it up, it will bug me.

How anal is that??

This condition goes back to my scale modeling days...I used to paint the INSIDE of the fuselage and wings, knowing full well that they would never again be seen once glued in place. I know, I've got a problem...please tell me I'm not the only one!? :eek:
 
cjensen said:
I know, but it's messy, and I don't like leaving things messy. If I don't clean it up, it will bug me.

How anal is that??

This condition goes back to my scale modeling days...I used to paint the INSIDE of the fuselage and wings, knowing full well that they would never again be seen once glued in place. I know, I've got a problem...please tell me I'm not the only one!? :eek:
Click to expand...

Chad, the guys who would leave that overspray there.....THEY'RE the one's with the problem.
 
Great question Chad

I have some overspray on my spars from priming all those nut plate countersinks. I forgot to tape the holes up and it looks like ****. I agree with cleaning it up. Thanks for asking the question!
 
Chad-
Did whatever you spray on that have any etching properties? If so, and if you remove the paint/primer, then the etching might have removed some of the corrosion protection the anodizing originally provided. Leaving it on there is not an indication of sloppy building, particularly if taking it off would lead to other potential issues. This could be one of those cases where fixing a "mistake" is more problematic than living with it, especially since as it stands right now you merely have a cosmetic issue in a place where no one will ever see it anyway. Just food for thought. Good luck though.
 
Well, I'm not sure what a self etching primer will do to an anodized surface, since it is already treated for corrosion protection thru the anodized process.

I've already cleaned it up, and as far as appearances go, there was no sign of discolorization or lightening of the gold color. I did use a self etching primer under that white topcoat, but it came right off with MEK, and looks much better now.

:cool:
 
Chad...

cjensen said:
I know, but it's messy, and I don't like leaving things messy. If I don't clean it up, it will bug me.

How anal is that??

This condition goes back to my scale modeling days...I used to paint the INSIDE of the fuselage and wings, knowing full well that they would never again be seen once glued in place. I know, I've got a problem...please tell me I'm not the only one!? :eek:
Click to expand...

Don't think of it as being anal... you're just trying to keep the weight down. :rolleyes:

Kent
 
I wish I could be more specific here, but I recently got something on my gold anodized rivet gauge and it totally destroyed the anodizing. I didn't notice the damage until days later, and really have no idea what it was. I often use acetone, paint thinner, window cleaner, aluma-prep (likely culprit) and various lubricants and polishes, but can't recall getting these things on my gauge. Anybody have any guesses?
 
It's more likely that you just removed the dye. That's not difficult. However, it is possible to dissolve the anodize with a caustic solution. I think (but am not sure) that aluma-prep is acidic, not basic. The amonia based window cleaner is weak, but still can't be good for the anodize.

By the way, here's a link on home anodizing if anyone wants to try it for themselves: http://astro.neutral.org/anodise.shtml

Guy
 
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