[jrebman]

Maybe I should ask if it can "successfully" be brass plated.

Looking at options for a bronze/brass finish top plate on an amp and if it is possible to plate aluminum with brass -- so that it will stay looking good for a long time -- that would be the simplest.  Otherwise I'll have to have a bronze plate machined and polished -- I have the machining resources for this, but it can get pricey.

Anybody know any brass plating places -- most of the ones I can find locally won't touch brass.

-- Jim

[jules]

I doubt it, though I could be wrong ...

brass is a mixture of zinc and copper so even if you could deposit it by electroplating, I suspect you could have trouble with electro-chemical stability with aluminium as a base.

You might be able to get a anodized finish that would be "bronze" in appearance though. Anodizing is a rather different process to plating  and works by bonding a coloured layer of some sort to a microscopically thin layer of oxide on the surface of aluminium.

jules

[Steve Eddy]

Hey Jim!

You sure you want to go with brass plating? I know brass is more expensive than copper, but most plating shops will have have a lot charge that's not exactly cheap either. The place here in town that does plating for me does brass plating but they have a $180 lot charge.

I don't know just how big a top plate you need, but McMaster-Carr has 12" x 12" x 1/8" brass sheet for $83.21. So unless you can find a shop that will do brass plating really cheap and doesn't have a lot charge, it can cost you rather more to plate brass on aluminum than to just go with solid brass.

By the way, copper can be plated on aluminum (they do that when they chrome plate copper) so there's probably a good chance they can plate it with brass.

se

[Imperial]

Caswell will plate brass onto aluminium.
http://www.caswellplating.com/ (Kits)

Imperial

[Imperial]

brass is a mixture of zinc and copper so even if you could deposit it by electroplating, I suspect you could have trouble with electro-chemical stability with aluminium as a base.

You could zincate the alu surface first, then the brass will adhere...
Anodic: Al + 3 OHn n> Al(OH)3 + 3en
Al(OH)3 n> AlO2n + H2O + H+
Cathodic: H+ + en n> H n> 1/2H2 (g)
...
Cathodic: Zn(OH)42n n> Zn2+ + 4 OHn
Zn2+ + 2en n> Zn (s)

When plating with brass, IE copper,  one should also use zinc sulfate rather than zinc oxide.. for a better result.
But as Steve Eddy says, it is a little tedious, and hence expensive... to brassify aluminum.

Imperial

[bpape]

The other option is to simply laquer it.

Bryan

[art]

Find someone who can anodise it the brass colour you desire. Easier and cheaper in the long run.

Worked for Jeff Rowland........

On second thought........you could use a local guy that I made the mistake of using once. He left a batch of front panels in the tank way too long, and they came out a funny yellow-like colour.

"You just said that you wanted them anodised. You didn't give me specifics. Take your (&**#^&$@+| parts, get the *&**^&&^&%& out of here, and don't ever come back!"

You will be relieved to know that he didn't charge me for the privilege of running a batch of front panels.

I think I sold them for scrap.......eventually.

Pat

[Steve Eddy]

Find someone who can anodise it the brass colour you desire. Easier and cheaper in the long run.

Worked for Jeff Rowland........

Well, unless one is willing to settle for one shade or another of "urine specimen" (i.e. alodine), I think one would be very hard pressed to find someone to do the color one desires that would be easier and cheaper than just going with solid brass or bronze.

se

[jrebman]

Thanks folks -- I really appreciate all the info and ideas.  I still am not sure which way I'm going to go, but at least now I have all the info I need for a range of options.  Great suggestions, everybody.

Sorry for not acknowledging sooner but I was in bed ill most of yesterday.

Thanks again,

Jim

[mgalusha]

Jim,

I can say the stuff from McMaster is quite nice. I laminated (glued) a sheet to the top of my DIY tube preamp and it came out very well. I used brass the first time but redid it using copper as I preferred the aesthetic of copper. I believe what I used was .062" thick.

Mike