Remove fingerprints from aluminum panels... Any tips/tricks?

[zackmd1]

So I did a search and not much popped up....

I got my MK4 delivered recently and have already assembled most of the cockpit aluminum (easy when you have no control arms...). My plan was to keep the engine bay aluminum bare while protecting it with a coating from everbrite. My issue is that these damn fingerprints will not come off... I have tried wax and grease remover, acetone, and lacquer thinner without any luck. My guess is the fingerprints are removed but that the aluminum as oxidized around them causing a more permanent stain. Does anyone have any tips or tricks to remove these? The time for a brushed aluminum look has past since they are installed and it would be near impossible to get a consistent pattern... My only thought is some type of etching cleaner to remove the top layer of oxidation?

[Rsnake]

A little gasoline on a rag or even some wd40 works great. With 5$ a gallon in California I would use wd40:D

[Kodiak]

MEK works well on aluminum. Gloves recommended

[zackmd1]

A little gasoline on a rag or even some wd40 works great. With 5$ a gallon in California I would use wd40:D

So WD40 looked to be the winner! "Removed" about 95% of the stains leaving just a very small hint behind. Unfortunately this is just temporary as cleaning with acetone (required prep for the protective coating) removes the WD40 leaving behind the full fingerprint stain. Same story with gas... That gave me an idea though! I cleaned the panel with acetone and coated a small area, sure enough the fingerprints mostly disappeared! We shall see if this is just due to the un-cured coating or if it will still hide the stains when fully cured (about an hour for full cure).

[zackmd1]

MEK works well on aluminum. Gloves recommended

Will try this next if the coating fails. Unfortunately it doesn't look like any stores in my area sell it though, amazon to the rescue...

[Norm B]

In the least visible spot you have (or a separate test panel) try wiping the black stained area with a little vinegar and then rinsing with distilled water. A cut lemon will also remove some of the black stains. After the stains are removed don't touch the aluminum until you coat it unless you have clean gloves on. It will etch immediately.

HTH

Norm

[NAZ]

If you're dealing with stains from oxidization, then you need an acidic cleaner. The best are made with hydrofluoric acid (not hydrochloric acid like you put in your swimming pool) like this Eastwood product that works fast:https://www.eastwood.com/ew-aluminum-prep-and-cleaner-quart-trigger-bottle.html But HF is probably the most dangerous chemical you will ever work with so extreme caution is advised and proper PPE is required. The Eastwood product works great but I would recommend you dilute it before using and work fast or you will end up over etching the panel. Just remember to add acid to water NOT THE OTHER WAY AROUND! Also, do a web search on HF safety before using as these consumer products containing HF do not list all the precautions necessary to keep you safe. This acid is easy to work with and fast acting but you must use it wisely.

[JohnK]

I will reinforce what NAZ is saying about the safety aspect of working with HF. I used to be a volunteer emergency response tech for a high tech company. HF was just one of many hazardous chemicals in the labs that we had to be trained to deal with exposures of. HF is particularly nasty in that it will not produce visible burns to the skin. Rather, it absorbs through the skin and begins to dissolve cartilage and bone. In short, you do NOT want to be accidentally exposed to HF. Take the PPE requirements very seriously.

[zackmd1]

And the winner is.....

Apple cider vinegar!

Odd to say the least but it has worked great! Seems to work slightly better then white vinegar at removing the fingerprints. Wiped "with the grain" with a vinegar soaked rag and then with a wet rag followed by wax and grease remover for the coating prep.

153526

Top right corner was treated while the rest of the panel was untreated.

153527

153528

[AC Bill]

How odd..never had that issue when I built mine. The aluminum must have been coated with something different back then.
I just used acetone to wipe them down, mainly to remove the black printing, fingerprints, grease, silicone, etc.

[NA5KAR]

For our Stainless appliances, we use a cleaner designed for that finish. It works like magic on finger prints. Comes in wet wipes and spray. You can get it at Home Depot. It may work on aluminum???

[NAZ]

Great! Vinegar is mildly acidic and appears to be just enough to remove the oxide layer. When I worked as an engineer for Anheuser-Busch making two-piece aluminum beer and beverage cans we used a combo of HF and sulfuric acid mixed with surfactants to rapidly clean the can bodies of oils and oxides before coating them. They would be so clean water wouldn't stick to the can and would instantly shed like it was coated with Rain-X. But leave them in the bath even a minute too long and they'd be frosty looking as that HF etches them in no time.

[AC Bill]

We used to use strong vinegar to etch the surface of brand new aluminum boats before painting. It allowed the paint to adhere.

[zackmd1]

Great! Vinegar is mildly acidic and appears to be just enough to remove the oxide layer. When I worked as an engineer for Anheuser-Busch making two-piece aluminum beer and beverage cans we used a combo of HF and sulfuric acid mixed with surfactants to rapidly clean the can bodies of oils and oxides before coating them. They would be so clean water wouldn't stick to the can and would instantly shed like it was coated with Rain-X. But leave them in the bath even a minute too long and they'd be frosty looking as that HF etches them in no time.

Thanks for the suggestion! I am pretty amazed at how well vinegar works after attacking these panels for quite some time with strong solvents with no luck. Here is a picture of the treated and coated passenger footbox. The coating is everbrite protectaclear. The coating acts more like a sealant, soaking into the aluminum and not leaving a noticeable overcoat. I have used this coating on many previous projects and have been impressed by the durability and finish.

153544

[NAZ]

Looking good Zack. That's shiny and clean looking. I usually take the basic patina approach to my tin work and don't sweat the paw prints, but I build race cars not show cars and they tend to look more industrial anyway.

I'll have to keep the Everbrite product in mind. I've used Sharkhide with good results and it lasts longer than I thought it would. But they're proud of that stuff as it's pricey.

[Norm B]

Glad the vinegar worked. Your panels look great. I am willing to bet that your apple cider vinegar is slightly stronger ( more acidic ) than your white, hence the better results. My next suggestion would have been CLR with a whole bunch of caution.

Norm

[Avalanche325]

Rather, it absorbs through the skin and begins to dissolve cartilage and bone.

I would opt for fingerprints before using that.

[NAZ]

There are many household products, painting products, and construction products that contain that acid. Chances are you've used it in something and never realized it.

It's not scary but does demand respect.