Amp Porn

[MantramAudio]

Here ya go.

That's right, work the camera, baby!

The hand polish is done. Yes, that's a reflection in the front panel of my GC chassis.

[Peter Daniel]

What exactly are you using to polish it? Can it be done with copper too?

[Steve Eddy]

Originally posted by Peter Daniel
What exactly are you using to polish it?

My guess would be simple wet/dry sanding to 600 or 1200 grit followed by some rubbing/buffing compound or jewler's rouge.

Can it be done with copper too?

I've put a high polish on brass and copper using the method above. Just takes a little elbow grease unless you've got a motorized buffer.

se

[Peter Daniel]

In case of copper, do you need any type of coating to protect it after? I'm using copper panels in my next amp.

[Steve Eddy]

Originally posted by Peter Daniel
In case of copper, do you need any type of coating to protect it after? I'm using copper panels in my next amp.

Sure. Just like brass it'll start darkening. If you want something permanent, you'll need to go with something like a hot dip lacquer, but otherwise a coat of paste wax can keep it looking good for a while.

se

[DrewP]

The slightest finger print will mark copper. The acid from the oils on your skin will begin to stain the surface and the only way to get the marks off again is more polishing. The longer the print is left, the worse it'll get. Commonly handled or touched sections will darken up really fast, rapidly ruining a uniform copper polished surface.

Although every single finger print will show up on stainless, they rub off just as easily without etching.

Copper panels MUST be laquered if they are not to look absolutely shocking.

My 2c

drew

[Variac]

As has been mentioned before, Incralac lacquer is the only thing to use on copper based metals, and it does work.

OK OK here's a place to get it (and some damar for your speakers)

http://www.consemp.com/catalog/f.html

[Peter Daniel]

I know all that about copper, but I'm after some sort of "weathered" finish. I'm not looking for shiny polished copper, as this will not much the rest of exterior. I'm afer the look you get when the copper pipes are exposed to elements and nothing can stain them anymore.

Is there a technique to achieve that type of permanent finish without further need for lacquers? I noticed that heating speeds up the proccess of getting copper oxidized. When it's evenly oxidized, it shouldn't accept stains from handling anymore.

I'm using that type of cork on the sides and frame (top, bottom and fronts) is made with copper bars.

[MantramAudio]

Originally posted by Peter Daniel
What exactly are you using to polish it? Can it be done with copper too?

The chassis started as a regular sheet of .090 6061 aluminum. I then sheared it to size on a sheet metal shear, and broke it into a |_| shape on a sheet metal break.

Then, I sanded with 220 grit sandpaper on a random orbital sander. This left much deeper marks than I first thought. I then wet sanded with 800, 1000, and 2000 grit wet sandpaper. After that, I started hand rubbing using a regular O'Cello (cellulose) sponge and Blue Coral liquid metal polish. This came from Wal-Mart. I repeated this process 12-15 times.

This is certainly possible with copper and brass, just start with the 1000 grit paper. Once you get the finish you want, clean VERY well with mineral spirits to clean up all the residue that the metal polish leaves. Then clean with a good spray-n-wipe cleaner. Rinse well with water, and dry thoroughly. I then wiped with alcohol to do a fine de-grease.

Next, I would appyly a clear laquer, probably a spray. Let dry well, then spray again. Then wet sand with some 1000 grit paper, and spray again. Finally, polish with a paste type auto polishing compound. This is finer than rubbing compound, but has more abrasives than regular wax. I did this with a copper J-Pole ham radio antenna and it looked great outdoors for years.

[Da5id4Vz]

I watched an artist accelerate the patina on some copper leaf that he had applied to a wall he was painting. He had a couple of spray bottles different strengths of mild acids in them. It was a long time ago but I think he told me he was using copper sulfate (is that an acid?) and some kind of vinegar. He was defiantly gong for a green patina witch I think is more extreme than you are looking for.

To experiment, you could try polishing up some pennies and dropping them in glasses with different concentrations.