Hi to all:
I want to have a custom made front panel anodized - here comes my problem:
I checked some anodizers here in Germany, always with the same result:
Today´s finishes, brushed or sanded, are not as glossy, not as soft to the touch, not so deep in colours, as they used to be, for example, in the eighties. But still you can find those glossy aluminium front panels in the next hifi store: Look at front panels from Denon, Marantz, Yamaha.
I am not talking about plastic which imitates brushed aluminium.
But look also at today´s gear from small High End manufacturers: Dull and rough to the touch. Black looks like grey. Today´s standard. Again, dust off your Sony or Nakamichi gear from the eighties: Brushed Aluminium, but soft to the touch, glossy with deep blacks.
What i know for sure those glossy finishes are also simply anodized.
They are chemically not different, but treated somehow different before anodizing.
No paint to achieve this look.
So, what I need to know is at least one of the suppliers for those front panels, get into contact with them and let me tell the trick. Does anyone in this forum who knows about that?
All the best, Salar
I want to have a custom made front panel anodized - here comes my problem:
I checked some anodizers here in Germany, always with the same result:
Today´s finishes, brushed or sanded, are not as glossy, not as soft to the touch, not so deep in colours, as they used to be, for example, in the eighties. But still you can find those glossy aluminium front panels in the next hifi store: Look at front panels from Denon, Marantz, Yamaha.
I am not talking about plastic which imitates brushed aluminium.
But look also at today´s gear from small High End manufacturers: Dull and rough to the touch. Black looks like grey. Today´s standard. Again, dust off your Sony or Nakamichi gear from the eighties: Brushed Aluminium, but soft to the touch, glossy with deep blacks.
What i know for sure those glossy finishes are also simply anodized.
They are chemically not different, but treated somehow different before anodizing.
No paint to achieve this look.
So, what I need to know is at least one of the suppliers for those front panels, get into contact with them and let me tell the trick. Does anyone in this forum who knows about that?
All the best, Salar
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The differences you note may be related to the mechanical finishing of the panels before anodizing. Since the anodized layer is very thin it seems that it should not greatly affect the feel of the panel surface. I would use silicon carbide wetsanding to take the finish of the panel to the desired level of smooth "brushing" (finishing at somewhere between 600 and 1200 grit) before anodizing.
Thanks for all the hints! Still, even thought being normally between 5-50µm thick,
the acid bath needed to clean the part and prepare for anodizing will dull the aluminium, but it can also be to "polished" chemically in the acid bath.
Nothing to try at home, especially with some custom-milled parts, relatively complicated, where you have only one shot. so it has to be a professional anodizer.
But maybe somebody will show up, to tell the trick. ..
Having a bit of an interest in chemistry myself, I discussed this subject with an industrial chemist some time ago. According to him, the difference is almost certainly due to cost cutting measures. Basically most consumer junk is sold on looks and not literal feel. And the color can frequently be adjusted in an ad to show true black etc. So it no longer makes much economic sense to keep a 'high grade' anodizing pipeline running in order to accommodate the few remaining quality conscious customers.
In particular the following details has something to say in the quality of the finished anodizing:
*) Surface finish, as already mentioned, obviously plays a role.
*) Aluminum alloy used. Not all Aluminum alloys are equally well suited for anodizing. And it is frequently too expensive to stock a particular alloy just for, say, front panels.
*) Time spent in the chemical baths. Time is money(tm). The slower the reactions are allowed to run, the more even the end result becomes. Ten times more current is ten times the productivity, and way coarser Aluminum oxide crystals.
*) Custom shaped cathodes to ensure an even (and low) current density across the anodized object. Only really feasible for large scale production runs. For small runs and oddly shaped objects, you just crank up the current and close your eyes...
*) Slow plus ultrasonic agitation of the electrolyte during the chemical treatments (including cleaning/oxide stripping). The microscopic bubbles, which forms as part of the oxidation and cleaning processes, needs to be continuously removed. Only really possible through strong, ultrasonic agitation of the fluids. The slow agitation (stirring) is to ensure an even temperature and concentration of chemicals during the processes.
*) Temperature control, cooling, to reduce and control the reaction speed, Ie. slow it down. No longer wanted. Gogogo!
*) Time spent out in the air between cleaning and anodizing.
*) Deliberate contamination of the anodizing electrolyte. This allows you to make the Aluminum oxide a deep yellow or brown color, which helps if the intended color is black. But this is obviously not something you do, if you want to use your chemicals to make anodizing of any color.
*) Quality of dyes used for coloring. This is a general problem for large scale manufacturing in many branches of industry. The 'good' dyes are still available, but are very expensive for general manufacturing due to the increased cost of environmentally safe disposal of the waste products. Also see car colors for more on this.
Bottom line is I suspect your suppliers are well aware of how to do a high quality anodizing, but they cannot justify actually running the process, including spending the time to dial in the process between production runs.
- Frank.
In particular the following details has something to say in the quality of the finished anodizing:
*) Surface finish, as already mentioned, obviously plays a role.
*) Aluminum alloy used. Not all Aluminum alloys are equally well suited for anodizing. And it is frequently too expensive to stock a particular alloy just for, say, front panels.
*) Time spent in the chemical baths. Time is money(tm). The slower the reactions are allowed to run, the more even the end result becomes. Ten times more current is ten times the productivity, and way coarser Aluminum oxide crystals.
*) Custom shaped cathodes to ensure an even (and low) current density across the anodized object. Only really feasible for large scale production runs. For small runs and oddly shaped objects, you just crank up the current and close your eyes...
*) Slow plus ultrasonic agitation of the electrolyte during the chemical treatments (including cleaning/oxide stripping). The microscopic bubbles, which forms as part of the oxidation and cleaning processes, needs to be continuously removed. Only really possible through strong, ultrasonic agitation of the fluids. The slow agitation (stirring) is to ensure an even temperature and concentration of chemicals during the processes.
*) Temperature control, cooling, to reduce and control the reaction speed, Ie. slow it down. No longer wanted. Gogogo!
*) Time spent out in the air between cleaning and anodizing.
*) Deliberate contamination of the anodizing electrolyte. This allows you to make the Aluminum oxide a deep yellow or brown color, which helps if the intended color is black. But this is obviously not something you do, if you want to use your chemicals to make anodizing of any color.
*) Quality of dyes used for coloring. This is a general problem for large scale manufacturing in many branches of industry. The 'good' dyes are still available, but are very expensive for general manufacturing due to the increased cost of environmentally safe disposal of the waste products. Also see car colors for more on this.
Bottom line is I suspect your suppliers are well aware of how to do a high quality anodizing, but they cannot justify actually running the process, including spending the time to dial in the process between production runs.
- Frank.
Hello Knarf - Frank!
Thank you very much for this explanation. I guess that´s why one cannot find
those shiny and smooth surfaces not so often any more.
And I guess, when you mold, mill and anodize aluminium "inhouse", you´ll have more control over the process. So cleaning in an acid bath might not tale so much time, a process that dulls the surfac.
Audionet and Stromboli, a german producer for High End gear and the company milling and anodizing the front panels/cabinets for audionet even claim to have
the aluminium exclusively molded for their needs because "off the shelf" aluminium (also those types for anodizing) is of bad quality with inclusions and impurities.
An anodizer I know happened to experience about 30% loss because of bad material.
Well, I hope, I can find an anodizing company, preferabely a small one, that will take it´s time and be cautious about the front panels.
Again, they are single items, no room for a second try...
All the best,
Sal
Thank you very much for this explanation. I guess that´s why one cannot find
those shiny and smooth surfaces not so often any more.
And I guess, when you mold, mill and anodize aluminium "inhouse", you´ll have more control over the process. So cleaning in an acid bath might not tale so much time, a process that dulls the surfac.
Audionet and Stromboli, a german producer for High End gear and the company milling and anodizing the front panels/cabinets for audionet even claim to have
the aluminium exclusively molded for their needs because "off the shelf" aluminium (also those types for anodizing) is of bad quality with inclusions and impurities.
An anodizer I know happened to experience about 30% loss because of bad material.
Well, I hope, I can find an anodizing company, preferabely a small one, that will take it´s time and be cautious about the front panels.
Again, they are single items, no room for a second try...
All the best,
Sal
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