Help corroding a metal surface

[JimRayden]

I need to make a Hammond box look like it's been left in a damp forest in the mud for a few decades. Tried etching but it doesn't look "damaged" enough. Any quickie-tricks?

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Jimbo

[JimRayden]

And no, leaving it in a damp forest in the mud for a few decades is not an option in this case.


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Jimbo

[Paul Perry (Frostwave)]

Depends what kind of damage you want, either the "lumpy surface" or "blotchy surface" look.
I'd try painting "leafy and twiggy" patterns on it in nail varnish, then corroding it with hydrochloric acid, then rubbing various shades of brown and black paint into the rough surface.
That's just a suggestion though, I havn't done this.
Also it depends whether it is just for a photoshoot, or whether you want a giggable box.

[markm]

Just a thought but, what if you just dunked it in salt water?
Or, Take some FeCl on a damp rag and rub it liberally all over the surface of the enclosure.....it may make it look "weathered" a bit.
I have often thought about "relicing" a new build ala Fender. 

[John Lyons]

Check out my post about "Copper Plating" a while back. It's not repeatable so much but one box turned out really nice.

John

[Hiwatt25]

My chemistry professor always used to say, "Water is the universal solvent" so I'd say Mark is probably on to something.  If you've got a few days, try salt water.  What if you scratch it up real well first?  That might hasten corrosion.  You could also put a bunch of rocks in a sock and give it a few good whacks if you want to disfigure the thing a bit. 

[markm]

My thoughts were the salt water would actually darken the aluminum quite a bit.
Afterall, plain unprotected aluminum usually "blackens" from weather to look like a real dull grey.
The FeCl method would certainly stain the aluminum blackish.....in theory anyway.....I've never tried either so, YMMV.

[JimRayden]

Thanks for al the suggestions, I'll make some saturated saltwater and dip it into that for a few days.

Oh wait, did you mean just saltwater or saltwater with electrolysis going on?

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Jimbo

[John Lyons]

Here's what mine turned out like



And the link  http://www.diystompboxes.com/smfforum/index.php?topic=54333.0

John

[blanik]

JL's copper plating is closer to the rusty look you want, cause if you'd leave a hammond box in a damp forest it wouldn't look good, aluminium doesn't rust well like iron... alu becomes all spotted with white spots... not really interesting... if you'd get steel cases (non stainless steel) the would rust in a week outside...


R.

[JimRayden]

Oh John, that's excellent, exactly the result I'm looking for. Time to bring out my plating gear.

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Jimbo

[markm]

Sorry, didn't realize it was the rusty look you were trying to acheive..........

[Seljer]

JL's copper plating is closer to the rusty look you want, cause if you'd leave a hammond box in a damp forest it wouldn't look good, aluminium doesn't rust well like iron... alu becomes all spotted with white spots... not really interesting... if you'd get steel cases (non stainless steel) the would rust in a week outside...


R.

I believe you can get special iron paint in craft stores, which you then rust up with another chemical to apply a rust finish to whatever surface (wood, plastic...whatever you can paint)

[QSQCaito]

What about muriatic acid?? The one used in pools. Place a few drops and in a couple of days you'll get a ver rusty surface.

[markm]

Ya know, there are also "antiquing" kits that are sold at arts & crafts stores.

[Seljer]

What about muriatic acid?? The one used in pools. Place a few drops and in a couple of days you'll get a ver rusty surface.

muriatic acid = hydrochloric acid

it was mentioned before that aluminium doesn't really "rust" as iron does. It does corrode, a layer of aluminium oxide forms on the surface which then stops further corrosion, which is not really as much of a visual effect as rust on iron

Though it does react with hydrochloric acid. I believe you'd need to sand the surface first since it probably won't work on the layer of aluminium oxide, to what I know it would create aluminium chloride and hydrogen gas........I believe this was all covered in one of the enclosure etchant threads

[JimRayden]

Sorry, didn't realize it was the rusty look you were trying to acheive..........

Any kind of really old look and natural looking damage is welcome, rust being perhaps the most welcome as it has that visual something and can look like real piece of art at times.

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Jimbo

[oldschoolanalog]

I haven't tried this but... Oven cleaner might be worth a try. Outdoors. Nasty stuff.

[antojado]

This sound like it might work:

http://en.wikipedia.org/wiki/Galvanic_corrosion

Lasagna cell
A "lasagna cell" or "lasagna battery" is accidentally produced when salty food such as lasagna is stored in a steel baking pan and is covered with aluminum foil. After a few hours the foil develops small holes where it touches the lasagna, and the food surface becomes covered with small spots composed of corroded aluminum.

This metal corrosion occurs because whenever two metal sheets composed of differing metals are placed into contact with an electrolyte, the two metals act as electrodes, and an electrolytic cell or battery is formed. In this case, the two terminals of the battery are connected together. Because the aluminum foil touches the steel, this battery is shorted out, a significant electric current appears, and rapid chemical reactions take place on the surfaces of the metal in contact with the electrolyte. In a steel/salt/aluminum battery, the aluminum is higher on the electrochemical series, so the solid aluminum turns into dissolved ions and the metal experiences galvanic corrosion.

And you can eat it when you're done! 

[Hiwatt25]

Just to throw this thread waaaay off topic, I used to live in Seattle and remember an engineer from Boeing telling me that they didn't use lead pencils when marking the fuselage of a plane because when to unlike metals touch, you'll get an reaction that will eventually corrode and I'd wager that corrosion on a jumbo jet is a bad thing. 

Of couse Boeing also announced that they saved a MILLION dollars a year by consolidating the different types of pens they used.   Imagine saving a million bucks by choosing to buy one brand of pen instead of ten.  You could build a lot of pedals for a million bucks and they could all have mojo components.