tardishead
Well-known member
Thought I would share my experiences etching anodised aluminium faceplates.
I first experimented with this when I was building an analogue synth a few years ago. I always loved the faceplates of the vintage Moog modules in the Modular range. I found out that this was done with Metalfoto - a product which is now discontinued. Basically it is aluminum panels anodised black which is covered in KPR - Kodak Photoresist. You then put the panel with your artwork in a UV exposure unit. Expose the KPR and then etch the panel with Caustic Soda. Caustic is also the product used to develop the photoresist so the timing of the process was always important.
I tried to emulate this. Being in Australia I could not get KPR which is generally not on the market anymore but is available at some places in USA.
So I got aerosol Electrolube photoresist and started to experiment. Basically in short I got it to work after a few hiccups. What I did was coat the anodised panel in resist about 2 light coats - baked it dry with a hairdryer - left them to settle. Developed the PR in a UV exposure unit with my artwork. Make a solution with one teaspoon of caustic soda granules and 1 litre demineralised water. Heat this solution to about 30 or 40 degrees.
Then I immerse the panel in the solution - lightly brushing the area to be etched with a fine paint brush. Quite quickly the graphics start to appear. Wait til the graphics are as shiny as possible and then quickly take out of the solution and put in a bucket of water to stop the panel etching any more.
Seems cool hey but there were always problems.
First professional transparencies always work better than any inkjet printable stuff - believe me I have tried many. The thing is the untreated parts have to be completely opaque otherwise it will not work properly.
Even the best examples of this technique I could not stop the covered black anodise from etching a little. The caustic seems to penetrate the resist and take some sheen off the anodise. I suppose it needs maybe another coating of resist and maybe exposing for longer in the UV unit. Trouble is if you put too much resist on it does not seem to develop.
The whole setup has to be dust proof. If anything gets on the panel while the resist is being sprayed it will dislodge in the etching process - tiny hairs and fluff etc which will leave marks.
I will take some photos to show you guys how my panels look. They are pretty cool I like them but they are far from perfect. They look aged - not completely shiny.
So the main problem is the use of photoresist and the fact that caustic soda which you need to etch the anodise also develops the photoresist.
So when I saw the other post about the etch-matic it got me thinking about other possibilities. A stencil that would not be affected by caustic soda would obviously be a complete winner. I wondered if the stencils used in the etchomatic product would be good to caustic etch anodise aluminium. The stencil would have to be fixed firmly to the panel so the etching solution could not spread beyond the developed area. Possibly some kind of temporary fixer would be good.
I imagine the process would work like this. Lay the panel flat with the stencil fixed on top and then lightly poor the etch solution and brush slightly til the area is etched.
Any chemists out there - would love to hear your thoughts.
Graphics etched in anodise looks fantastic and I was ever so close standardising my method. The stencil method could be better.
Or maybe what would be even better is a spray photoresist that would not be effected by caustic soda - and hence would need to be developed by some other chemical.
I first experimented with this when I was building an analogue synth a few years ago. I always loved the faceplates of the vintage Moog modules in the Modular range. I found out that this was done with Metalfoto - a product which is now discontinued. Basically it is aluminum panels anodised black which is covered in KPR - Kodak Photoresist. You then put the panel with your artwork in a UV exposure unit. Expose the KPR and then etch the panel with Caustic Soda. Caustic is also the product used to develop the photoresist so the timing of the process was always important.
I tried to emulate this. Being in Australia I could not get KPR which is generally not on the market anymore but is available at some places in USA.
So I got aerosol Electrolube photoresist and started to experiment. Basically in short I got it to work after a few hiccups. What I did was coat the anodised panel in resist about 2 light coats - baked it dry with a hairdryer - left them to settle. Developed the PR in a UV exposure unit with my artwork. Make a solution with one teaspoon of caustic soda granules and 1 litre demineralised water. Heat this solution to about 30 or 40 degrees.
Then I immerse the panel in the solution - lightly brushing the area to be etched with a fine paint brush. Quite quickly the graphics start to appear. Wait til the graphics are as shiny as possible and then quickly take out of the solution and put in a bucket of water to stop the panel etching any more.
Seems cool hey but there were always problems.
First professional transparencies always work better than any inkjet printable stuff - believe me I have tried many. The thing is the untreated parts have to be completely opaque otherwise it will not work properly.
Even the best examples of this technique I could not stop the covered black anodise from etching a little. The caustic seems to penetrate the resist and take some sheen off the anodise. I suppose it needs maybe another coating of resist and maybe exposing for longer in the UV unit. Trouble is if you put too much resist on it does not seem to develop.
The whole setup has to be dust proof. If anything gets on the panel while the resist is being sprayed it will dislodge in the etching process - tiny hairs and fluff etc which will leave marks.
I will take some photos to show you guys how my panels look. They are pretty cool I like them but they are far from perfect. They look aged - not completely shiny.
So the main problem is the use of photoresist and the fact that caustic soda which you need to etch the anodise also develops the photoresist.
So when I saw the other post about the etch-matic it got me thinking about other possibilities. A stencil that would not be affected by caustic soda would obviously be a complete winner. I wondered if the stencils used in the etchomatic product would be good to caustic etch anodise aluminium. The stencil would have to be fixed firmly to the panel so the etching solution could not spread beyond the developed area. Possibly some kind of temporary fixer would be good.
I imagine the process would work like this. Lay the panel flat with the stencil fixed on top and then lightly poor the etch solution and brush slightly til the area is etched.
Any chemists out there - would love to hear your thoughts.
Graphics etched in anodise looks fantastic and I was ever so close standardising my method. The stencil method could be better.
Or maybe what would be even better is a spray photoresist that would not be effected by caustic soda - and hence would need to be developed by some other chemical.
