Brushed Aluminum look on Amp

pbc

Member
2010-10-09 7:54 pm
So I bought an old Sunfire 5 CH amp, and it was pretty beaten up on the left side, top and right side (but especially the left).

Wanted to try refinishing it as I can remove the face plate (which is in good shape).

Any tips as to how I can get a similar look?

Here is the right side ...

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And here is what it looks like "new" ...

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Thanks guys...
 

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Johnny2Bad

Member
2010-05-04 7:51 pm
The anodizing process will affect the metal in two ways. It will harden the aluminum outer (exposed) layer and it will color the metal.

You can re-anodize the metal if you want. Low-volume anodizing can be difficult to source, however. It almost certainly will alter the color somewhat, but if the shade of your new anodizing layer is generally consistent with the old you can get good results. Areas that are raised above the original finish should be taken down to the same level as the new unit once had; no need to be too aggressive here, though. Just enough for a flat surface is good.

You should carefully assess the condition of the metal if anodizing is desired, as this is generally the surface that will most easily show flaws. If there are deep gouges, etc it may not be the best option, as these will still exist after refinishing, or you may have to finish as outlined below, by taking the hard anodized layer off.

If you choose to refinish beyond a simple re-anodizing, such as changing the anodizing color significantly, or obtaining a natural aluminum finish, you will have to penetrate the hardened layer down to softer aluminum. It is normally only a few microns deep, but that does depend somewhat on the quality of the original anodizer's work. Evenness can be an issue; you don't want high and low spots where hard anodizing remains in some areas while you are abrading softer aluminum underneath.

You may want to consider a painted finish on top of the existing anodized layer. This can give good results and you have many finish choices. It almost certainly will be the easiest.

If you do choose to finish the bare metal itself, a large sheet of sandpaper taped to an extremely flat surface is handy to avoid an uneven finish. Generally a large sheet of glass or mirror is excellent in this case, as it's very flat. You must be careful to avoid further damaging the surface, by moving the work only in the existing finish direction. It is very easy to make things worse if you're not careful.

In a low-volume production environment with aluminum or stainless steel, it's very common to use a belt sander to apply the brushed finish. This allows you to keep the brushed finish consistent and in one direction only. Be careful as it can remove a lot of metal quickly.

If it were me, and I was only interested in fixing the two sides, I would use paint. The top complicates things a bit, as it has a factory anodized finish that matches the front, but if you're willing to compromise a bit, you could paint it as well in the same color. That may work fine if you normally stack items on the amp or if it's always somewhat recessed in a rack or shelving.

Be sure to carefully clean the metal before painting. Wear gloves to avoid re-contaminating the metal with oils from your hands.
 
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