The authoritative public forum
  for Metal Finishing since 1989
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ANODISING AND PHOTORESIST

Hi everyone
is there a photoresist product available to consumers that will allow me to selectively caustic etch and anodise aluminium at will? I tried to do this with a Electrolube PRP200 photoresist which is made for PCB manufacture - but as soon as we put it in a caustic etch solution it washed off. Also the anodisers said that they doubted whether the resist would be able to stand the high temperature acid baths anyway.
This is probably a proprietary product but my friend runs an old school anodisers and I am sure he could order the product through his suppliers.
I looked into getting some aliuminium panels professionally anodise printed and it was ridiculously expensive - way above my budget.

the other idea is can I buy anoprint ink as a consumer?

Mike Burnham
Tardis Studio - Sydney, Australia
2005

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2005

If you have a friend who has an anodizing shop, and if this isn't a large quantity order, you could try silk screening or painting the dye on yourself prior to sealing the part. Basically, you would etch and anodize the entire piece, then apply what dyes you need, then seal in hot water or hot nickel acetate.

Good luck.

Jim Gorsich
Compton, California, USA

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A interesting problem! Basically you want a photoresist that you can image (obviously!) but that withstand both acid and alkali. The problem here is that the more common positive photoresists are stable in acide but unstable in alkali. Negative photoresists are stable in alkali but unstable in acid. As far as I know there is no photoresist available that offers the protection (or lack of!) that you need. However, you do not say exactly what you are doing, so how about coating the aluminium plates with candle wax and then scratching the image into the wax to penetrate the metal. It can then be etched and anodised without too much hassle. However, perhaps this will not give you the required resolution.

Trevor Crichton
R&D practical scientist
Chesham, Bucks, UK
2005