Metal finishing Q&As since 1989


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Sculptor attempting to give stainless steel a blue finish , can anyone help ?

Hello everyone, firstly thanks for your time you are providing a very generous service to the less technically minded . My name is Derek Saul and am a sculptor working in Cape Town South Africa , I have been awarded a commission to make a map of the world for a South African company , the size of the map is 6 meters long by 3 meters high . The company is involved in mining so the map is to be made from different metals - bronze for the continents , aluminum for the polar regions and stainless steel for the sea. The continents I am sculpting in relief with all the geological features present , this I am doing in clay which I will then take a mould from and then cast in my backyard foundry , similar for the polar regions .
The sea I have been sculpting directly onto 2mm stainless plate using my TIG welder to build up the various ridges and valleys of the sea bottom . The sea is as one piece with the above dimensions and nearly complete . Here comes my problem - is there any way one can patina with chemicals or some other method to change the colour of the stainless steel towards a blue colour , I am a bit nervous of using my blow torch as I'm not too confident that I can consistently achieve a heat blue and I cannot locate a company with a kiln big enough to fit my sculpted into or for that matter know what is the exact temperature to achieve consistent blue , I would most appreciate some help on this matter if it is at all possible and as much information as possible , the stainless is grade 304 .



With Thanks
Derek Saul

Derek Saul
Sculptor - Cape Town, Western Province, South Africa
2007

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Derek,
Master's Magic @ Master's Magic.com sells a non-grain raising blue stain that you can spray over the ocean areas with a paint spray gun. It is methanol (alcohol) based and is a WONDERFUL sea blue color that if lightly sprayed (misted) over the metal area will coat those areas beautifully.

Stephen Mann
- Palm Springs, California, USA
2007

Stainless steel(18Cr/8Ni+rest Fe) can be blued by anodic oxidation in sulfuric acid/sodium dichromate solution(1 lit acid D.1,24 gm/cm3+7,5 gm sodium dichromate,70-95 °C temp., 0,06 A/dm2, 1,3 v,lead cathode, 10 minutes).Hope it helps and good luck!

Goran Budija
- Cerovski vrh Croatia
2007