Ganp
Enlightened
For the uninitiated like myself getting something anodised can be problematic. Finding an anodising business willing to accept one-offs, or even small batches, can be difficult, and costs for small quantities are comparatively high.
The surface finish on the alloy will make a big difference to the final appearance, and it is essential that the anodisers know what alloy type they are treating for you - especially for hard anodising. Some alloy grades can not be hard anodised. In my simplistic understanding of the process they can not withstand the much higher current used during this process and the surface suffers badly. When things don't turn out as expected it would be all too easy to blame the anodisers, so I consult them before sending anything, and get their advice on preparation and finishing. I'm learning slowly.
But I'm still making mistakes. My latest was to assume that all alloy types which can be hard anodised can be treated together.
I sent several items of 6082 aluminium (the UK equivalent of 6061) and two of 7075 - and I did not tell the anodisers of the 7075 - so everything got treated as 6082.
Here is my 7075 McR45 head and bezel before anodising ...
And here it is after going through the process with some 6082 items ... a sort of pebble dash finish.
Very luckily for me the anodisers offered to chemically remove the anodising - for free - so that the items could be re-anodised properly. Unluckily of me, the first anodising had left quite a texture on the surface, so after they were stripped I had to re-machine them to get a good finish. But there is still some pitting left because I dared not remove too much metal. And all of this meant that the tolerances on the fine bezel threads were out - so I ended up having to make a new bezel too.
Another shock when it came back after re-anodising. Instead of the bronze tint I was expecting it was a flat grey colour. It looked OK on a grey body but it was not going to look good with a typical HA natural finish body.
I washed it to see what happened. While it was wet it took the colour I had expected - but it just dried back to grey again.
So there was nothing left to do except put a little oil on the bezel threads and slick them up a bit.
WTF, the bezel threads took the expected colour. Just a dab of oil on the inside confirmed it. So I went for broke and oiled the whole head.
Voila!! ... Here it is ... sort of bronzy looking.
I tried washing and degreasing it to see if it would turn grey again, but it didn't. It just went it a little less shiny. So, apart from a little pitting in places it now looks as I expected. But I don't know what gives with the grey finish. The guy I asked at the anodisers didn't know either.
Was I supposed to apply oil to bring out the colour? ... I didn't think so. So what is going on?
If this is a known phenomena, or an accepted practice, I would like to know. Anodising is costly enough without me making unnecessary mistakes.
Colin.
The surface finish on the alloy will make a big difference to the final appearance, and it is essential that the anodisers know what alloy type they are treating for you - especially for hard anodising. Some alloy grades can not be hard anodised. In my simplistic understanding of the process they can not withstand the much higher current used during this process and the surface suffers badly. When things don't turn out as expected it would be all too easy to blame the anodisers, so I consult them before sending anything, and get their advice on preparation and finishing. I'm learning slowly.
But I'm still making mistakes. My latest was to assume that all alloy types which can be hard anodised can be treated together.
I sent several items of 6082 aluminium (the UK equivalent of 6061) and two of 7075 - and I did not tell the anodisers of the 7075 - so everything got treated as 6082.
Here is my 7075 McR45 head and bezel before anodising ...
And here it is after going through the process with some 6082 items ... a sort of pebble dash finish.
Very luckily for me the anodisers offered to chemically remove the anodising - for free - so that the items could be re-anodised properly. Unluckily of me, the first anodising had left quite a texture on the surface, so after they were stripped I had to re-machine them to get a good finish. But there is still some pitting left because I dared not remove too much metal. And all of this meant that the tolerances on the fine bezel threads were out - so I ended up having to make a new bezel too.
Another shock when it came back after re-anodising. Instead of the bronze tint I was expecting it was a flat grey colour. It looked OK on a grey body but it was not going to look good with a typical HA natural finish body.
I washed it to see what happened. While it was wet it took the colour I had expected - but it just dried back to grey again.
So there was nothing left to do except put a little oil on the bezel threads and slick them up a bit.
WTF, the bezel threads took the expected colour. Just a dab of oil on the inside confirmed it. So I went for broke and oiled the whole head.
Voila!! ... Here it is ... sort of bronzy looking.
I tried washing and degreasing it to see if it would turn grey again, but it didn't. It just went it a little less shiny. So, apart from a little pitting in places it now looks as I expected. But I don't know what gives with the grey finish. The guy I asked at the anodisers didn't know either.
Was I supposed to apply oil to bring out the colour? ... I didn't think so. So what is going on?
If this is a known phenomena, or an accepted practice, I would like to know. Anodising is costly enough without me making unnecessary mistakes.
Colin.
